A fast, lightweight load calculator for construction sites and logistics work. Estimate material weights, check against support limits, and get an instant PASS/OVERLOADED status — no account, no paywall, no dependencies.
Load building
- Add multiple materials in a single calculation — mix lumber, gravel, cinder blocks, and more
- Edit or remove individual items without clearing the whole load
- Load Items list grouped inside Step 1, directly below the Add to Load button
- Running weight total and Load vs. Limit gauge displayed in a Live Summary card inside Step 1
- Empty state placeholder shown when no items have been added; Clear all hidden until items exist
Materials
- Built-in library of common construction materials (lumber, drywall, gravel, steel pipe, and more)
- Multi-token search across name, unit, type, aliases, and tags
- Filter by material type: rigid, loose, or stackable
- Add and save custom materials with your own name, unit, weight, and handling notes
Safety calculation
- Three support types: Scaffold (500 lbs), Hoist (1,000 lbs), Truck (5,000 lbs)
- Three distribution types with capacity reduction factors:
- Even — no reduction
- Off-Center — 25% reduction
- Top-Heavy — 40% reduction
- Distribution and Support dropdowns displayed side-by-side in a 2-column grid
- Live gauge showing current load vs. adjusted limit (green / yellow / red) — activates after first Calculate
- Near-limit caution when load exceeds 90% of capacity
Workflow
- Guided three-step layout: Select Materials → Set Load Conditions → Calculate
- Steps 2 and 3 are dimmed and non-interactive on load; each unlocks as the previous step is completed
- Step badges animate from grey to orange as each step becomes active
- Calculate button disabled until at least one item is added
- Inline validation errors next to the relevant fields
- Distribution type hint text explaining each option
Presets
- Save named load configurations (items + distribution + support) to localStorage
- Load or delete saved presets at any time
- Collapsible section with bookmark icon prefix, orange left border accent, and smooth expand/collapse transition
Results
- Per-item weight breakdown with totals
- Safety Factor row always shown with a plain-language buffer hint (e.g. "1.5× — 50% safety buffer applied")
- Support Comparison table with PASS ✓ / WARN / FAIL ⚠ badges and row hover states
- Copy Result is the primary action (orange); Save as Image and Export CSV are secondary
- Recent calculation history with increased touch targets, hover states, and wrapping text
- Print-friendly layout via browser print (Ctrl+P)
Units
- Toggle between lbs and kg — all displays update instantly
- Preference saved to localStorage
- lbs/kg toggle sits inline next to the Quantity/Volume input in Step 1
Most load calculation tools are locked behind paywalls or overloaded with features. LoadCalc is a fast, offline-capable alternative for:
- Construction site planning
- Warehouse and logistics work
- Estimating safe scaffold, hoist, or truck loads
- Select Materials — search or filter, pick a material, enter a quantity, and tap + Add to Load. Added items appear immediately below with a running total and live summary. Step 2 unlocks once at least one item exists.
- Set Load Conditions — choose how the load is distributed and what it's riding on. Step 3 unlocks once both fields are filled.
- Calculate — get a full weight breakdown, Safety Factor hint, and PASS/OVERLOADED result against the adjusted limit. The Support Comparison table shows how the load fares across all support types.
Support limits and distribution reduction factors are representative typical values based on common industry references. Always verify against your specific equipment's rated capacity and consult a qualified engineer or supervisor before making load decisions on a job site.
- HTML5
- CSS3
- Vanilla JavaScript (ES modules, no frameworks)
- Vitest for unit tests
npm install
npm test # run unit tests
npm run lint # check for lint errors
npm run lint:fix # auto-fix lint and formattingUX & Layout (March 2026)
- Step progression locking — Steps 2 and 3 are dimmed on load and unlock progressively as each step is completed. Step badges animate from grey to orange.
- Load Items grouping — the item list, Clear all button, and Load Summary card (running total + gauge) are now all contained within Step 1. Clear all is hidden until items exist; an empty state placeholder is shown otherwise.
- Unit toggle relocated — the lbs/kg toggle moved from the header to sit inline next to the Quantity/Volume input. The header now shows only the offline badge.
- Results panel polish — Safety Factor always shown with a plain-language buffer hint. PASS badges prefixed with ✓, FAIL with ⚠. Copy Result is the primary action button; Save as Image and Export CSV are secondary. Support Comparison rows have hover states.
- Recent history — heading made more prominent with a divider above it. Rows have min 44px touch targets, hover states, and text wraps instead of truncating.
- Presets & Custom Materials — both sections are collapsible with smooth expand/collapse transitions, icon prefixes, and an orange left border accent.
- Layout cleanup — Distribution and Support dropdowns in a side-by-side 2-column grid. Disclaimer and version tag moved to a dedicated site footer.