Scrap Rate Calculator

Calculate the percentage of produced units classified as scrap and the remaining non-scrap count. Scrap rate (%) = scrap units ÷ total units × 100. Non-scrap units = total units − scrap units. The denominator is all produced units, including scrap, not only the remaining units.

Assumptions & limits

• Enter whole-unit counts: total units must be from 1 to 9,007,199,254,740,991, and scrap units from 0 to total units. These are safe-integer limits of this implementation. Fractional, negative, empty and non-finite values are rejected.
• Both counts must describe the same batch or reporting period and the same unit type. Count a unit once in the total and, if it is scrap, once in the scrap subset.
• The result is based on unit counts, not scrap weight, material value or financial loss. This tool has no rework, inspection or first-pass outcome fields. Its remaining count is only total minus scrap.

18 scrap units among 600 total units in one batch.

1. Use all 600 produced units as the denominator: 18 ÷ 600 = 0.03.
2. Convert to a percentage: 0.03 × 100 = 3%.
3. Subtract the scrap count: 600 − 18 = 582 non-scrap units.

3% scrap rate and 582 non-scrap units.

Scrap 0 and total 0 are rejected because there is no denominator. Scrap 0 with total 600 is valid and gives 0% scrap and 600 non-scrap units. Scrap 601 with total 600 is rejected because the subset exceeds the total; all 600 units being scrap is valid and gives 100%.

The example means 3% of the counted batch was marked as scrap. The other 97% is the arithmetic non-scrap share; this calculator cannot call it first-pass yield or prove it passed inspection because no such outcomes are entered. Confirm that the total includes scrap before comparing rates across batches. A unit-based percentage alone does not calculate a cost.

• Scrap rate is scrap units divided by total produced units. Multiplying by 100, subtracting the scrap count and taking the complementary percentage are arithmetic derived from that ratio. Lean & Environment Toolkit, Chapter 3 (process metrics)

Whole-count limits and the non-scrap output describe this implementation. The synthetic batch is not a quality benchmark. No first-pass yield, acceptance status or cost is inferred from these two inputs.