Calculations

How to Calculate Tooling, Mold, and Die Cost Per Part

The core amortization, cost-per-part, and tool-life formulas worked out with real inputs, so you can run the numbers yourself.

Start with tooling amortization, the backbone of every other number here. The formula is Cost Per Part = Tool Cost / Amortization Volume. If a progressive die costs 84,000 dollars and the program commits to 600,000 parts, the amortized tooling cost is 84,000 / 600,000 = 0.14 dollars per part. Pull the tool cost from the toolmaker quote (design, cut, tryout, and texturing included) and the volume from the signed PO or the EAU multiplied by program years. The Tooling Amortization calculator does this and lets you split cost across multiple part numbers running from the same die.

Mold cost per part adds cavitation and a projected life cap. Use Cost Per Part = Mold Cost / (Cavities x Rated Shots), but never amortize past the mold's rated life. A 4-cavity mold at 62,000 dollars rated for 500,000 shots yields 4 x 500,000 = 2,000,000 parts, so 62,000 / 2,000,000 = 0.031 dollars per part. If your annual demand is 250,000 parts, the mold lasts 8 years of shots, meaning demand, not tool life, sets your amortization window. The Mold Cost Per Part and Die Cost Per Part calculators separate rated-life capping from demand-driven amortization so you do not overstate volume.

Tool life cost captures the perishable insert side, which amortization ignores. The formula is Tool Cost Per Part = Insert Cost / (Edges x Parts Per Edge). A carbide insert at 18 dollars with 4 usable edges cutting 220 parts per edge gives 18 / (4 x 220) = 0.0205 dollars per part. Parts per edge comes from your CAM feed data or a tool-life log, not the catalog optimistic figure. Add regrind cost where applicable: a 40-dollar regrind restoring 3 more edges at 200 parts each changes the denominator. The Tool Life Cost calculator handles multi-edge inserts and regrind cycles in one pass.

Changeover loss converts downtime into a per-part penalty you can compare against tooling spend. Use Loss Per Part = (Changeover Minutes x Machine Rate Per Minute) / Parts Per Run. A die swap taking 45 minutes on a press costed at 3.20 dollars per minute across a 5,000-part run adds (45 x 3.20) / 5,000 = 0.0288 dollars per part. Cut the run to 1,000 parts and the same changeover balloons to 0.144 dollars per part, five times higher. The Die Changeover Loss and Mold Changeover Cost calculators make this run-size sensitivity explicit so you can size batches deliberately.

Fixture ROI answers whether a fixture pays for itself through cycle-time savings. Net Savings Per Part = (Baseline Cycle Seconds minus New Cycle Seconds) x Labor Rate Per Second minus Fixture Amortized Cost Per Part. If a 950-dollar fixture cuts load time by 22 seconds at a fully burdened 0.61 dollars per second, you save 22 x 0.61 = 13.42 dollars per part in labor, dwarfing the fixture cost over any real volume. Payback Parts = Fixture Cost / Net Savings Per Part, so 950 / 13.42 = 71 parts. The Fixture ROI and Fixture Payback calculators return both the per-part gain and breakeven count.

Maintenance and spares belong in true cost per part, and both are often left out. Maintenance cost per part is Annual PM and Repair Spend / Annual Parts. A mold needing 3,200 dollars of PM, cleaning, and weld repair per year at 250,000 parts adds 3,200 / 250,000 = 0.0128 dollars per part. Spare tooling carrying cost is Spare Value x Carrying Rate / Annual Parts; a 6,000-dollar spare cavity set at a 20 percent carrying rate adds 1,200 / 250,000 = 0.0048 dollars per part. The Tooling Maintenance Cost and Spare Tooling Inventory calculators keep these small but real numbers in the total.

Stack the pieces to get fully loaded tooling cost per part. Using the mold example: 0.031 amortization plus 0.0205 perishable tooling plus 0.0288 changeover plus 0.0128 maintenance plus 0.0048 spares equals 0.0979 dollars per part, roughly triple the naive amortization-only figure of 0.031. That gap is why quotes built on amortization alone lose money. Keep every input in consistent units, dollars per part throughout, and confirm your volume basis matches across all lines, either rated life or committed demand, never a blend within a single calculation.

Two checks catch most arithmetic errors. First, verify the amortization volume against reality: if committed volume exceeds tool-rated life, cap it at rated life and plan a replacement tool, otherwise your per-part number is fictitiously low. Second, sanity-test changeover loss against batch size, since a run below 1,000 parts often makes changeover the single largest tooling line, larger than amortization itself. Run each formula in isolation first, then combine, and re-derive the total by hand on one representative part number before trusting a spreadsheet across a hundred SKUs.

Published 2026-07-01.