Heat Treatment, Furnaces & Thermal Processing calculator
Fixture Load Capacity Calculator
Find the whole-part count allowed by three documented loading limits. Enter fixture payload, tare, part weight, usable positions, planned quantity and furnace gross allowance.
What this calculator does
- Find whole-part capacity from fixture payload, furnace gross load and usable positions.
Formula used
- Fixture weight limit = floor(fixture payload allowance ÷ part weight)
- Furnace weight limit = floor((furnace gross allowance − fixture tare) ÷ part weight)
- Part capacity = minimum(fixture weight limit, furnace weight limit, usable positions)
- Planned gross weight = planned parts × part weight + fixture tare
- Part count margin = part capacity − planned parts
Inputs explained
- Fixture Payload Limit: Documented distributed payload rating at the operating temperature.
- Fixture Tare Weight: Empty fixture and tray weight included in furnace loading.
- Weight per Part: Weight of one part on the approved loading plan.
- Usable Part Positions: Whole positions preserving approved spacing and support.
- Planned Parts: Whole parts intended for this fixture charge.
- Furnace Gross Load Limit: Documented furnace allowance including fixture tare.
How to use the result
- Best suited to fixture loading plan checks, weight versus position constraints.
- Does not calculate fixture stress, creep or remaining service life. All parts use the entered unit weight.
Current U.S. benchmarks
- Industrial electricity averages 9.77 cents per kWh across the U.S. (EIA, Jul 2026), up 4.7% from a year earlier. Energy-intensive steps carry this directly into unit cost.
Common questions
- Does fixture payload include the empty fixture? No. Enter its documented parts payload separately from the tare. The furnace gross limit includes both.
- Why round down the weight limits? Only complete parts can be loaded. A fractional result cannot add another part without exceeding a weight allowance.
- Can I use the room-temperature fixture rating? Use a rating applicable to the actual process temperature, distribution and fixture condition. The calculator does not derate material strength.
- What if there are enough positions but too much weight? The smallest limit governs. Reduce the part count or use a documented loading arrangement with adequate capacity.
Last reviewed 2026-10-06.