Calculations

How to Calculate Core Recovery, Recycling Yield, and Remanufacturing Metrics

The five formulas that run a circular operation, computed line by line with real inputs, units, and worked examples.

Start with Core Recovery Rate, the input that feeds every downstream number. The formula is cores recovered divided by units sold in the matching cohort, times 100. If you sold 12,000 alternators in 2023 and collected 8,400 returnable cores by mid-2025, recovery rate is 8,400 / 12,000 = 70 percent. Pull cores recovered from your take-back receiving log and units sold from the sales system for the same model and vintage. Match the cohort window to the product life, roughly 18 to 30 months for automotive rotating electrics, or the ratio reads artificially low. The Core Recovery Rate calculator handles cohort lag automatically.

Not every recovered core is usable, so apply a core acceptance yield before you plan production. If 8,400 cores arrive and inspection scraps 1,260 for cracked housings, seized bearings, or missing components, acceptance yield is (8,400 - 1,260) / 8,400 = 85 percent, leaving 7,140 build-ready cores. Keep the scrap categories separate, because irreparable damage and merely worn parts drive different replacement costs later. Feed the 7,140 figure, not the 8,400, into any capacity or throughput plan. Confusing gross receipts with net usable cores is the single most common overstatement in reman planning.

Recycling Yield measures how much saleable material you extract from a feedstock stream. The formula is recovered output mass divided by input feed mass, times 100. Shred and separate 1,000 kg of mixed end-of-life electronics and recover 240 kg copper, 180 kg aluminum, 90 kg steel, and 30 kg circuit board fines, and total recovered mass is 540 kg, a 54 percent yield. The remaining 460 kg is plastics, glass, and dust routed to secondary processing or landfill. Weigh input at the infeed scale and output after final separation. The Recycling Yield calculator lets you track yield per material grade so a drop in copper recovery does not hide behind a stable blended number.

Material Recovery Value converts those masses into dollars. For each stream, multiply recovered mass by market price per unit mass, then sum. Using the batch above with copper at 8.20 dollars per kg, aluminum at 1.90, and steel at 0.28: copper is 240 x 8.20 = 1,968 dollars, aluminum is 180 x 1.90 = 342, steel is 90 x 0.28 = 25.20, totaling 2,335.20 dollars per tonne of feed. Prices come from a spot index like LME or a scrap buyer quote, so timestamp them; a 15 percent copper price swing moves this batch by roughly 295 dollars. The Material Recovery Value calculator stores per-grade prices and revalues instantly.

Reuse Payback tells you when reusing an asset beats buying new. The formula is refurbishment cost divided by the per-cycle savings versus new. If reconditioning a returnable steel pallet costs 6.50 dollars and a new pallet costs 22 dollars, savings per reuse is 15.50 dollars, so payback happens after 6.50 / 15.50 = 0.42 cycles, effectively the first reuse. For a heavier case, a remanufactured hydraulic cylinder costing 340 dollars to rebuild against 900 new saves 560 per cycle and pays back inside one cycle. Where refurb cost approaches new-buy cost, payback stretches past the asset's remaining life and reuse stops making sense. The Reuse Payback calculator flags that break-even.

Circular Material Savings quantifies virgin material displaced. Multiply units built from recovered content by the virgin mass avoided per unit. Build 7,140 reman alternators that each reuse 3.1 kg of recovered steel and 0.4 kg of copper, and you displace 7,140 x 3.5 = 24,990 kg, or about 25 tonnes of virgin material. Convert to embodied impact by multiplying by a material factor, for instance 1.9 kg CO2e per kg of primary steel. Source the per-unit reused mass from a teardown bill of materials, not a nameplate weight, because fasteners and consumables are usually new. The Circular Material Savings calculator ties this back to your build volume.

Chain the formulas so one output feeds the next and check units at every hand-off. Units sold feed Core Recovery Rate; recovered cores times acceptance yield give build-ready cores; build-ready cores drive Circular Material Savings; and the same recovered masses that set Recycling Yield also set Material Recovery Value. A frequent error is mixing bases: recovery rate uses matched cohort units, yield uses batch mass, and savings uses actual build count, which is usually smaller than available cores because of demand limits. Keep mass in kg and rates as decimals throughout, then convert to percent only for reporting, and the arithmetic stays consistent end to end.

Published 2026-07-01.