Results update as you edit; there is no Calculate button. The starting values are an example. Replace them with your member and loading. Save & compare beam options ↓
Point: a single force at a position. On a 20 ft member, enter position 10 ft for a load at the middle. Positive force acts down; negative force acts up.
Distributed: a uniform load between Start and End. Over a 10 ft region, 50 lb/ft is equivalent to 500 lb using Total Over Region. Switching these two input modes converts the value for the current region.
Moment: an applied turning effect at a position, always in lb·in. Positive is clockwise (CW); negative is counterclockwise (CCW). For example, 100 lb·ft = 1,200 lb·in.
Units: the inches/feet selector converts member length, support and load positions, and restraint spacing. Section dimensions remain inches; forces remain lb; distributed intensity remains lb/ft; applied moments remain lb·in.
After edits: recheck the diagram and load values when changing load type or member length. Point loads default to midspan for Simply Supported and follow the center as length changes. Enter a custom position to stop automatic movement; use “Center load & follow length” to restore it. Other automatic load positions and distributed-load end positions follow the member end until edited. Custom positions are preserved when switching supports. Support B also follows the length until edited.
Utilization compares demand with the capacity or limit used by this model. Factor of safety (FOS) compares the modeled strength capacity with demand. Read the individual rows as well as the overall result.
Deflection is calculated even when its limit check is Off. Turn the check On to evaluate your chosen limit. Here L is the full member length, including any overhang. For L = 240 in, L/360 allows 0.667 in. A larger denominator permits less movement. The optimizer appears for supported standard sections when this check is On.
SCREEN OK: evaluated strength meets your selected safety factor and any active deflection check passes. MARGINAL: strength is below your selected safety factor, but modeled capacity and any active deflection limit are not exceeded. EXCEEDS LIMIT: a strength capacity or active deflection limit is exceeded. INVALID INPUT: correct the listed input issues before interpreting results.
Not evaluated means the tool has not checked that item. A passing screen covers only the checks performed. The optimizer uses your selected strength safety factor (default 2.0) and deflection limit; its suggestions require review for your application.
Save → edit → save → compare. Save a baseline, then try a C-channel, W-shape, or rectangular tube and verify its steel grade. Select up to three saved options to compare with the live current design.
Each save stores all inputs and a snapshot of the calculated results. Load replaces the current inputs, so save your current work first. Duplicate makes a copy; Delete removes a save immediately. Saved results reflect the calculator at the time of saving; Load recalculates them. Saves stay in this browser and do not travel with the HTML file. Unsaved inputs reset on reload.
For a fair shape comparison, keep length, supports, applied loads, and deflection criteria the same. Self-weight changes automatically with the section. This tool supports steel grades only; Custom Fy does not change steel stiffness or density. Compare the individual checks and any “not evaluated” notes before choosing a section.
On a narrow screen, swipe horizontally inside either table to see the other options and actions.
Results are calculated using linear-elastic Euler–Bernoulli beam theory for a uniform prismatic member, with a steel modulus of elasticity of approximately 29,000 ksi. The tool calculates bending stress, an approximate shear-yield screen (τ = V/Aw compared to an assumed 0.6·Fy capacity), deflection, and factor-of-safety/utilization results based on the yield strength selected for the section. Results reflect only the section properties, material, loads, and support conditions entered and represent the capabilities and limitations of the current calculation model — they do not account for every possible loading condition, material behavior, or failure mode, including but not limited to torsion, lateral-torsional buckling, local/shear buckling, code-specific shear reductions, load interaction effects, fatigue, or connection design. An optional Lateral Restraint / Girt Spacing Guide is available for applicable W, S, and C profiles; it provides a preliminary Lp-based spacing advisory only and does not perform a lateral-torsional-buckling capacity check or brace design.
MechTCalc is intended as a calculation and preliminary analysis tool and does not constitute a complete structural or mechanical design. Users are responsible for verifying that the inputs, assumptions, and results are appropriate for their specific application. Where required, results should be independently reviewed by a qualified professional and evaluated against the applicable standards, specifications, codes, and project requirements.