Cantilever Steel Beam Calculator
The Cantilever Steel Beam Calculator provides accurate analysis for overhang and projecting beams with free-end conditions. Calculate reactions, maximum moment at support, deflection, shear, and AISC-compliant checks for cantilever steel beams.
Optimized for common cantilever scenarios, including balconies, awnings, decks, and swing sets. Input span, uniform or point loads (including at free end), and section properties — instantly receive support moment, tip deflection, shear diagram, utilization ratios, safety factors, and beam weight.
Supports steel sections with LRFD/ASD methods and clear visual diagrams. Perfect for engineers and DIY users. For full multi-support beam design, visit our Ultimate Steel Beam Calculator.
Cantilever Steel Beam Calculator – Overhang, Deflection & AISC Design
Fixed-Free Beam Analysis • AISC 360 / Eurocode 3 • Deflection • Stress • LTB Checks
Distance from fixed wall to free tip
0 = pure cantilever. Enables uplift check at anchor.
For LTB check. Leave blank to use full span.
Default: 200,000 MPa (29,000 ksi) for steel
1.5–2.0 for swing sets, crane arms; 1.0 for static
| Parameter | Value | Units | Limit / Capacity | Status |
|---|
Share your results or export to PDF for engineering review and building permit submission.
Maximum Tip Deflection
\[\delta_{max} = \frac{P L^3}{3 E I}\]Slope at Free Tip
\[\theta = \frac{P L^2}{2 E I}\]Deflection at Distance x from Fixed End
\[\delta(x) = \frac{P x^2}{6 E I}(3L - x)\]Where: P = point load [kN], L = span [m], E = elastic modulus [GPa], I = moment of inertia [m⁴]
Maximum Tip Deflection
\[\delta_{max} = \frac{w L^4}{8 E I}\]Slope at Free Tip
\[\theta = \frac{w L^3}{6 E I}\]Deflection at x from Fixed End
\[\delta(x) = \frac{w x^2}{24 E I}(x^2 - 4Lx + 6L^2)\]Where: w = distributed load intensity [kN/m]
Maximum Tip Deflection
\[\delta_{max} = \frac{M_0 L^2}{2 E I}\]Slope at Free Tip
\[\theta = \frac{M_0 L}{E I}\]Superposition for Multiple Loads
\[M_{total} = \sum_{i} M_i\]The principle of superposition allows independent effects to be added.
Elastic Bending Stress
\[\sigma_b = \frac{M_{max}}{S_x} = \frac{M_{max} \cdot c}{I_x}\]LRFD Strength Check
\[\text{DCR} = \frac{M_u}{\phi_b M_n} \leq 1.0\] where \(\phi_b = 0.90\) and \(M_n = F_y \cdot Z_x\) (compact section yielding)Plastic Limit
\[L_p = 1.76\, r_y \sqrt{\frac{E}{F_y}}\]Elastic Limit
\[L_r = 1.95\, r_{ts} \frac{E}{0.7 F_y}\sqrt{\frac{J \cdot c}{S_x \cdot h_0} + \sqrt{\left(\frac{J \cdot c}{S_x \cdot h_0}\right)^2 + 6.76\left(\frac{0.7 F_y}{E}\right)^2}}\]Inelastic LTB (L_p < L_b ≤ L_r)
\[M_n = C_b\left[M_p - \left(M_p - 0.7 F_y S_x\right)\frac{L_b - L_p}{L_r - L_p}\right] \leq M_p\]Elastic LTB (L_b > L_r)
\[M_n = F_{cr} \cdot S_x \leq M_p\]| Application | Typical Limit |
|---|---|
| General cantilever | L/180 |
| Roof / canopy | L/240 |
| Occupied floors / balconies | L/360 |
| Vibration-sensitive | L/480 |
Guideline: f_n > 4 Hz acceptable for occupied floors (AISC Design Guide 11). f_n > 8 Hz for sensitive equipment.
Click any row to load section properties into the calculator. Properties shown for strong-axis bending.
| Section | d (mm) | bₑ (mm) | A (mm²) | Iₓ (mm⁴×10⁶) | Sₓ (mm³×10³) | Zₓ (mm³×10³) | rₖ (mm) | W (kg/m) |
|---|
Finds the lightest W-shape from the database that satisfies all strength, deflection, and LTB checks based on your current input parameters.
Click any preset to automatically populate typical spans, loads, and factors for that application. You can then customize the values.
| Application | Typical Span | Live Load | Dead Load | Deflection Limit |
|---|---|---|---|---|
| Residential Balcony | 1.5–3 m | 2.4 kN/m² (IBC) | 1.0–2.0 kN/m | L/360 |
| Canopy / Awning | 1.0–4 m | 0.5–1.5 kN/m² | 0.5–1.0 kN/m | L/240 |
| Jib Crane (light) | 2–6 m | 5–50 kN tip load | Beam self-weight | L/300–L/500 |
| Swing Set | 1.5–2.5 m | 2–3 kN (DLF 2.0) | Beam self-weight | L/240 |
| Signboard | 0.5–2 m | Wind-driven | Sign weight | L/150 |
| Mezzanine Edge | 2–4 m | 3.6 kN/m² | 2.0–3.5 kN/m | L/360 |
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Cantilever Steel Beam Calculator
Step-by-Step User Guide
Full documentation covering every input, formula, result, and engineering principle behind the calculator — from basic deflection checks to AISC 360 LRFD code compliance.
What Is a Cantilever Steel Beam?
A cantilever beam is a structural member that is rigidly fixed (clamped) at one end and completely free to deflect at the other end. Unlike a simply supported beam where loads spread between two supports, all bending resistance in a cantilever must come from the single fixed support.
Fig. 1 — Cantilever beam anatomy: fixed wall, applied loads, deflection curve, and key structural reactions. Maximum moment and shear always occur at the fixed support.
The key engineering challenge of a cantilever is that 100% of bending moment concentrates at the fixed end — unlike simply supported beams where moment distributes across the span. This makes it uniquely critical to get the calculations right.
Real-World Cantilever Applications
| Application | Typical Span | Primary Load Type | Critical Check |
|---|---|---|---|
| Residential balcony | 1.5 – 3.0 m | UDL live load (people) | Deflection L/360 |
| Canopy / awning | 1.0 – 4.0 m | Snow + wind UDL | Deflection L/240 |
| Jib crane arm | 2.0 – 8.0 m | Point load at tip | Bending stress + LTB |
| Swing set arm | 1.5 – 2.5 m | Dynamic point load (DLF 2.0) | Deflection + fatigue |
| Deck / floor overhang | 1.0 – 2.5 m | Dead + live UDL | Deflection L/360 |
| Signboard bracket | 0.5 – 2.0 m | Point + wind load | Tip rotation |
| Mezzanine edge beam | 2.0 – 4.0 m | Dead + live UDL (high) | Bending + vibration |
Step-by-Step User Guide
Follow these 7 steps in order to complete a full cantilever beam analysis. Each step maps directly to a section of the calculator.
Click SI / Metric for kN, m, MPa — or Imperial for kip, ft, ksi — in the top-right header toggle. All inputs and outputs switch instantly. Never mix units — this is the #1 source of calculation errors.
In the Inputs tab, under Beam Geometry, enter:
- Cantilever Span (L) — The projection length from the fixed wall face to the free tip. m or ft
- Back-Span Length (optional) — If the cantilever is part of a longer beam that continues back to another support, enter that back-span length. This enables uplift force calculation at the anchor.
- Unbraced Length (Lb) — Distance between lateral bracing points along the compression flange. Leave blank to default to the full span. m
Choose "Select from Database" to pick a standard W-shape, IPE, or HSS section by designation (e.g. W250x25). All section properties (I, S, Z, ry) auto-populate. Or choose "Enter Custom Properties" to manually type Ix, Sx, Zx, ry for non-standard or built-up sections.
Select a steel grade from the dropdown — yield strength (Fy) and elastic modulus (E) auto-fill from code values. You can override with custom values for special alloy steels.
| Grade | Fy (MPa) | Fy (ksi) | Fu (MPa) | Region |
|---|---|---|---|---|
| A36 | 250 | 36 | 400 | USA (structural) |
| A572 Gr.50 | 345 | 50 | 450 | USA (most common) |
| A992 | 345 | 50 | 450 | USA (W-shapes) |
| S275 | 275 | 39.9 | 430 | Europe / Eurocode |
| S355 | 355 | 51.5 | 510 | Europe (high strength) |
| Q345 | 345 | 50 | 470 | China / Asia |
Click + Point Load, + Distributed Load, or + End Moment to add load rows. For each load, specify:
- Load Category — D (Dead), L (Live), W (Wind), S (Snow). This controls LRFD load factors.
- Magnitude — Force in kN (point) or kN/m (distributed).
- Position — Distance from the fixed end.
0= fixed wall;L= free tip.
Toggle Include beam self-weight to automatically add the section's dead load. Toggle Apply LRFD factors to use factored loads for strength design.
Select your governing code (AISC 360, Eurocode 3, etc.) and deflection limit from the dropdown:
- L/180 — General cantilevers (most permissive)
- L/240 — Roofs, canopies (default)
- L/360 — Occupied floors, balconies (most strict)
- Custom — Enter any ratio
Set the Dynamic Load Factor (DLF) to 2.0 for swing sets or playground equipment; 1.5 for cranes; 1.0 for static loads.
Press the orange CALCULATE BEAM button. The calculator switches to the Results tab, showing: green/amber/red pass-fail verdict, demand/capacity ratio bars, a detailed results table, and a step-by-step derivation. Visit Diagrams for interactive shear force, moment, and deflection charts.
Input Parameters & Units Reference
Every input field in the calculator, with the accepted unit, valid range, and what it represents physically.
Imperial: 0.3 – 165 ft
Imperial: in⁴
Imperial: in³
Imperial: ksi
= 29,000 ksi
Unit Conversion Quick Reference
| Quantity | Metric Unit | Imperial Unit | Conversion Factor |
|---|---|---|---|
| Length (span) | m | ft | 1 m = 3.2808 ft |
| Length (section) | mm | in | 1 mm = 0.03937 in |
| Point Force | kN | kip | 1 kN = 0.2248 kip |
| Distributed Load | kN/m | kip/ft | 1 kN/m = 0.0685 kip/ft |
| Bending Moment | kN⋅m | kip⋅ft | 1 kN⋅m = 0.7376 kip⋅ft |
| Stress / Pressure | MPa | ksi | 1 MPa = 0.14504 ksi |
| Moment of Inertia | mm⁴ | in⁴ | 1 mm⁴ = 2.403×10⁻⁶ in⁴ |
| Section Modulus | mm³ | in³ | 1 mm³ = 6.102×10⁻⁵ in³ |
| Deflection | mm | in | 1 mm = 0.03937 in |
All Calculation Formulas Used — Detailed Explanation
Every formula used in the calculator, derived from Euler-Bernoulli beam theory and AISC 360 LRFD provisions. Formulas are rendered in LaTeX for precision.
Deflection Formulas
Deflection (δ) is the vertical displacement of the beam, maximum at the free tip. The calculator uses superposition to add individual load contributions.
Slope / Tip Rotation Formulas
Tip rotation (θ) is the angle of the beam's neutral axis at the free end. Excessive rotation causes visual tilt in balconies, water ponding, and equipment misalignment.
Bending Moment & Shear Force Formulas
Stress Calculation Formulas
LRFD Strength Capacity Formulas (AISC 360)
LRFD (Load and Resistance Factor Design) applies partial safety factors to both loads and material resistance, giving a more statistically reliable design than older ASD methods.
Lateral-Torsional Buckling (LTB) Formulas — AISC F2
LTB is a failure mode where the compression flange of the beam buckles sideways and twists. It is especially critical for cantilevers because the top flange is in compression over the full span and is often unbraced.
Serviceability — Deflection Limit Check
Natural Frequency (Vibration Check)
Back-Span Uplift Force
Understanding Your Results — Complete Interpretation Guide
After clicking CALCULATE BEAM, the Results tab shows every structural check. Here is exactly what each value means and how to interpret the color-coded indicators.
DCR Color System
| Result | Unit | Formula Used | Pass Condition | If it Fails |
|---|---|---|---|---|
| Max Deflection δmax | mm | wL⁴/(8EI) + superposition | δ ≤ L/Δ | Use deeper section; shorten span; reduce loads |
| Max Moment Mmax | kN⋅m | P·L or wL²/2 | M₹ ≤ ϕₛMₙ | Increase section modulus Zx; change section |
| Max Shear Vmax | kN | P + wL | V₹ ≤ ϕₚVₙ | Add web stiffener; increase web area A₩ |
| Bending Stress σₛ | MPa | Mmax / Sx | σ ≤ F₵ | Increase Sx; use higher-grade steel |
| Tip Rotation θ | degrees | PL²/(2EI) | θ ≤ 0.5° | Increase EI; reduce loads; check ponding risk |
| Safety Factor SF | — | F₵ / σₛ | SF ≥ 1.67 | Redesign with higher Zx or larger section |
| Natural Frequency fₙ | Hz | 3.516/(2πL²) × √(EI/m) | fₙ ≥ 4.0 Hz | Increase EI; add mass; provide damping |
| LTB Mode | — | Lp, Lr comparison | Yielding governs | Add lateral bracing; reduce Lₛ; use wider flange |
| Uplift at Anchor | kN | Mmax / Lbackspan | ≤ anchor capacity | Increase back-span; add hold-downs; add counterweight |
How to Read the Shear Force Diagram (SFD)
The SFD shows internal shear force along the beam length. For a cantilever with a point load at the tip, the SFD is a horizontal line equal to P across the full span, stepping to zero at the free tip. A UDL creates a linearly varying SFD, maximum at the fixed end and zero at the tip.
How to Read the Bending Moment Diagram (BMD)
The BMD shows internal bending moment. For a cantilever, moment is always zero at the free tip and maximum (negative / hogging) at the fixed wall. A point load creates a linear BMD; a UDL creates a parabolic curve.
How to Read the Deflection Curve
The deflection curve shows vertical displacement along the span. The fixed end has zero deflection. The curve increases toward the free tip, reaching δmax. If the curve exceeds the allowable deflection line, the serviceability check fails.
Common Mistakes to Avoid — Microcopy Guide
These are the most frequent errors users make. Each mistake is paired with the correct approach.
Entering the total beam length (including back-span) as the cantilever span L.
L = overhang distance only (wall face to free tip). Enter back-span separately in the Back-Span field.
Using the same units in some fields and different units in others (mixing kN with kip, or m with ft).
Set the unit toggle FIRST before entering any values. The toggle converts all labels but NOT previously typed numbers.
Ignoring self-weight. A W610x82 beam adds 0.80 kN/m dead load — significant for long cantilevers.
Always enable "Include beam self-weight." The calculator auto-calculates it from the section's listed kg/m weight.
Setting Dynamic Load Factor = 1.0 for swing sets or playground equipment (static analysis only).
Use DLF = 2.0 for swing sets; DLF = 1.5 for cranes/hoists; DLF = 1.3 for machinery with moderate vibration.
Leaving unbraced length = full span when the top flange is actually braced at mid-span.
Enter the actual distance between lateral supports as Lₛ. Shorter Lₛ gives higher LTB capacity (less reduction).
Selecting L/180 deflection limit for a balcony floor used by people (too lenient — floor will feel bouncy).
Use L/360 for occupied floors and balconies. L/240 for roofs. L/180 only for general non-critical cantilevers.
Entering section modulus Sx when the Plastic Modulus Zx is needed (they look the same unit but Zx is always larger).
For LRFD: use Zx (plastic modulus). For elastic/ASD stress checks: use Sx. Both are listed in the Section DB tab.
Classifying all loads as "Dead" to get lower LRFD factors (1.2D instead of 1.6L) — underestimates demand.
Use correct categories: permanent structure weight = D; people, furniture, equipment = L; snow = S; lateral pressure = W.
Input Validation Rules & Accepted Ranges
The calculator validates all inputs before computing. Here are the accepted ranges and what triggers a warning or error.
| Input Field | Min Value | Max Value | Warning Trigger | Error Condition |
|---|---|---|---|---|
| Span L | 0.1 m | 50 m | L > 10 m (long cantilever warning) | L ≤ 0 (no calculation) |
| Unbraced Length Lₛ | 0 | = L | Lₛ > L (capped at L) | Negative value |
| Moment of Inertia Ix | 1 mm⁴ | ∞ | — | 0 or negative |
| Section Modulus Sx | 1 mm³ | ∞ | Sx > Zx (physically impossible) | 0 or negative |
| Yield Strength F₵ | 100 MPa | 700 MPa | F₵ < 235 MPa or > 460 MPa | 0 or negative |
| Elastic Modulus E | 100,000 MPa | 300,000 MPa | E ≠ 200,000 ±10% | 0 or negative |
| Point Load P | 0 | ∞ | — | Negative value |
| Load Position a | 0 | = L | a > L (capped to L) | Negative value |
| Dynamic Load Factor | 1.0 | 3.0 | DLF > 2.5 (unusual) | < 1.0 (meaningless) |
| Deflection Limit | L/50 | L/1000 | — | Ratio < 50 (too lenient) |
Load Combinations — LRFD vs ASD Explained
The calculator supports two design philosophies. Toggle Apply LRFD factors to switch between them.
LRFD (Load and Resistance Factor Design)
LRFD multiplies loads by partial factors that reflect their uncertainty, and multiplies material capacity by a resistance factor (ϕ < 1.0) to account for material variability. The governing combination used by the calculator is:
ASD (Allowable Stress Design)
ASD uses unfactored service loads and compares resulting stresses to allowable values. No load factors are applied (DLF = 1.0 for load effects). The safety margin is embedded in the allowable stress:
| Load Type | LRFD Factor | ASD Factor | Description |
|---|---|---|---|
| Dead (D) | 1.2 | 1.0 | Permanent loads: beam weight, slab, fixed equipment |
| Live (L) | 1.6 | 1.0 | Occupancy loads: people, furniture, movable equipment |
| Snow (S) | 1.6 | 1.0 | Ground or roof snow loads |
| Wind (W) | 1.0 | 1.0 | Lateral wind pressure (also roof uplift) |
| Self-weight | 1.2 (as D) | 1.0 | Auto-calculated from section weight kg/m |
Steel Section Database — How to Read Section Properties
The Section DB tab lists all available sections with their structural properties. Understanding these values helps you make better section choices.
Fig. 2 — W-shape (wide flange) cross-section dimensions: d (depth), b, (flange width), t, (flange thickness), tw (web thickness). The neutral axis (N.A.) passes through the centroid at mid-depth for symmetric sections.
| Property | Symbol | Unit | Physical Meaning | Effect on Beam |
|---|---|---|---|---|
| Depth | d | mm | Overall section height | Larger d ↑ more I, more σ arm |
| Flange Width | b, | mm | Width of top/bottom flanges | Wider flange ↑ LTB resistance ↑ |
| Area | A | mm² | Total cross-sectional area | Proportional to weight (A×density) |
| Moment of Inertia | Ix | mm⁴ | Resistance to bending curvature | Higher Ix ↑ less deflection, lower σ |
| Elastic Section Modulus | Sx | mm³ | Ix / (d/2): elastic bending capacity | Higher Sx ↑ lower bending stress |
| Plastic Section Modulus | Zx | mm³ | Full plastic moment capacity | Zx > Sx; used in LRFD Mp = Fy×Zx |
| Weak-axis Gyration | ry | mm | √(Iy/A): LTB slenderness | Higher ry ↑ longer Lp, less LTB risk |
| Self-weight | W | kg/m | Mass per unit length | Included as dead load (×9.81/1000 kN/m) |
Application Presets — What Each One Pre-Loads
Each preset in the Presets tab auto-fills typical engineering values for that application type. You should verify and adjust values for your specific project.
| Preset | Span | Section | Loads Pre-filled | DLF | Def. Limit |
|---|---|---|---|---|---|
| Residential Balcony | 2.5 m | W250x33 | 1.0 kN/m Dead + 2.4 kN/m Live (IBC residential) | 1.0 | L/360 |
| Canopy / Awning | 3.0 m | W200x22 | 0.5 kN/m Dead + 1.2 kN/m Snow | 1.0 | L/240 |
| ⛽ Swing Set Arm | 2.0 m | W150x22 | 2.5 kN tip point load (Live) | 2.0 | L/240 |
| Jib Crane Arm | 4.0 m | W310x33 | 20 kN tip load (Live) | 1.5 | L/240 |
| Signboard Bracket | 1.5 m | W150x13 | 0.5 kN/m Dead + 1.0 kN tip Wind load | 1.0 | L/180 |
| Deck Overhang | 2.0 m | W200x22 | 1.5 kN/m Dead + 2.0 kN/m Live | 1.0 | L/360 |
| Mezzanine Edge | 3.0 m | W310x52 | 2.0 kN/m Dead + 3.6 kN/m Live (office) | 1.0 | L/360 |
| Workshop Shelf | 1.5 m | W150x22 | 0.5 kN/m Dead + 5 kN tip Live | 1.0 | L/240 |
Accuracy Statement & Limitations
This calculator implements Euler-Bernoulli beam theory with Kirchhoff assumptions (small deflections, linear elastic material, prismatic cross-section, plane sections remain plane). It is calibrated against AISC Steel Construction Manual examples and gives results within ±1% of hand calculations for the covered load cases.
Scope of calculations:
- Prismatic (uniform cross-section) steel beams only
- Linear elastic behavior (no plastic redistribution for continuous cantilevers)
- Euler-Bernoulli theory: shear deformation ignored (valid when L/d > 10)
- LTB uses AISC F2 equations with Cₛ = 1.0 (conservative for cantilevers)
- Deflection uses superposition of closed-form solutions — exact for the listed load types
- Shear deformation not included — may underestimate deflection by 3–10% for deep, short sections
This tool is intended for preliminary design and educational purposes only. Final structural designs for buildings, public structures, or any safety-critical application must be reviewed and stamped by a licensed Professional Engineer (PE) or Chartered Engineer (CEng) who takes professional responsibility for the design.
Frequently Asked Questions (FAQ)
Answers to the most common questions about cantilever beam design and how to use this calculator.
There is no single maximum — it depends on load, section, and deflection limit. Practical steel cantilever spans typically range:
- Residential balconies: 1.5 – 3.0 m (W200 to W310 sections)
- Commercial canopies: 2.0 – 6.0 m (W310 to W460 sections)
- Industrial crane arms: 3.0 – 10.0 m (W460 to W610 and above)
For long spans, deflection (L/360 check) typically governs before strength. Use the Optimize tab to find the minimum section for your specific span and load.
This can happen because DCR uses factored (LRFD) loads (1.2D + 1.6L) compared to ϕMₙ, while the Safety Factor (ASD) uses unfactored service loads compared to F₵. The LRFD method applies higher safety margins and is the more conservative check. If DCR bending > 1.0, the beam fails AISC 360 LRFD — regardless of the ASD safety factor. You should resize the section to bring DCR ≤ 1.0.
Lateral-Torsional Buckling (LTB) is when the compression flange of the beam buckles sideways before the section can develop its full plastic moment. "Inelastic LTB" means the unbraced length Lₛ is between Lₚ and Lᵣ — the section develops some plastic capacity but not the full Mₙ. Solutions:
- Add lateral bracing along the compression flange to reduce Lₛ
- Use a section with a wider flange (larger b,) for better LTB resistance
- Increase the section size (larger rₖ increases Lₚ)
- Use an HSS section (closed section has much better torsional resistance)
This calculator is optimised for steel beams only. However, you can use it for reinforced concrete by entering a custom section with the appropriate transformed Iₓ for the cracked section, and using E = 30,000 MPa (typical for concrete). Note that:
- The LTB check is not applicable to concrete (no lateral buckling of compression zone)
- The yield strength F₵ should not be interpreted as reinforcement yield — instead compare σₛ against 0.45fʹс (ACI) for compression, or use moment capacity from ACI 318 separately
- Long-term creep deflection in concrete is not included — multiply deflection by 2.0–3.0 for sustained loads
For a full concrete cantilever analysis, use a dedicated RC beam calculator.
Always defer to a licensed local engineer. This calculator:
- Does not account for local code amendments that may require higher load factors
- Does not check connection details (welds, bolts at the fixed support)
- Does not account for notches, holes, or fabrication imperfections
- Does not model partial fixity (assumes perfectly rigid connection at wall)
- May use different load models than required by your local authority
Use this tool for preliminary sizing and educational understanding. The engineer of record (EOR) who stamps the drawings is legally responsible for the final design.
Multiply the area pressure (kN/m²) by the tributary width (m) of the beam:
w [kN/m] = q [kN/m²] × tributary width [m]
Example: 2.4 kN/m² live load on a 1.5 m wide balcony = 3.6 kN/m on the cantilever beam. For two beams sharing the load, tributary width = 1.5/2 = 0.75 m, giving 1.8 kN/m per beam.
W250x25 is a North American W-shape per AISC; IPE 240 is a European parallel-flange I-section per Eurocode. Key differences:
- W-shapes have slightly thicker flanges relative to web, optimised for US practice. Used with AISC 360.
- IPE sections have tapered flanges (narrower at tips) and are lighter per unit depth. Used with Eurocode 3.
- W250x25: Ix = 48.7×10⁶ mm⁴, W = 25 kg/m. IPE 240: Ix = 38.9×10⁶ mm⁴, W = 30.7 kg/m.
- Use W-shapes if procuring in North America; use IPE if sourcing in Europe/Asia.
Yes, best practice is to target DCR ≤ 85–90% for serviceability checks like deflection. A 98% DCR leaves almost no margin for:
- Load variability (actual loads often exceed nominal values)
- Connection flexibility (real fixity is never 100% — adds to deflection)
- Long-term effects (permanent dead loads cause creep deflection over time)
- Future load changes (added weight, changed use)
Use the Optimize tab to find the next available section with a more comfortable margin. The additional cost of one size up is almost always worth the reliability.
On the Results tab, use the Print / Export PDF button (calls browser print dialog, save as PDF). This captures:
- All input parameters with units
- Complete results table with pass/fail for every check
- Step-by-step derivation showing all formulas and intermediate values
- Demand/Capacity ratios
For official permit submissions, the PDF should be accompanied by a cover sheet from the Engineer of Record (EOR) confirming the design parameters and taking professional responsibility. Many jurisdictions require a PE/CEng stamp on structural calculations submitted with permit applications.
Yes — use the Back-Span Length input to model this. When a back-span is entered:
- The calculator computes the uplift reaction at the back-span anchor (holds-down force required at the far support)
- The cantilever portion is still analyzed as a pure fixed-free cantilever for deflection and stress
- You should also manually check the back-span portion separately (simply supported, same loads) using the deflection formula δ = 5wL⁴/384EI
For a full continuous beam analysis with multiple spans, you will need a more advanced tool such as a moment-distribution calculator or FEA software.
