How do you calculate no-fault-found rate?

Divide no-fault-found units by total diagnosed units and multiply by 100. With 8 NFF units out of 250 diagnosed, the rate is 3.2%.

What is a good no-fault-found rate for electronics?

It varies by product, but mature consumer electronics depots often see 10-30% NFF, and best-in-class programs push below 10%. The 3.2% in this example is excellent and suggests genuine failures dominate the return stream.

Why is no-fault-found rate so costly?

Each NFF unit incurs inbound and outbound shipping, intake admin, and full diagnostic bench time but generates no repair value. A high rate means you are paying full process cost to confirm nothing is wrong.

What causes a high NFF rate?

Common drivers are confusing user setup, false or overly sensitive trouble codes, lenient field return policies, and intermittent faults your test station cannot reproduce. The root cause is usually upstream of the depot.

How is the gap to target interpreted here?

The gap is your actual rate minus the target. With a 3.2% rate against a 95% target field, the displayed gap is 91.8 points; in practice you want NFF far below such a high reference, so read the gap in the direction that matches how your target was defined.

NFF rate vs first-pass yield — what's the difference?

First-pass yield measures units that pass test the first time in production. NFF rate measures returned field units that show no defect on the bench. One is a production-line metric, the other a reverse-logistics quality metric.

Electronics Repair, Refurbishment & Depot Operations calculator

No-Fault-Found Rate Calculator

No-fault-found (NFF) rate is the share of returned units that pass full diagnosis with no defect reproduced. It is one of the most expensive hidden costs in depot operations: every NFF unit consumes bench time, shipping, and admin without a billable repair, and it usually points to a problem upstream of the depot — confusing setup, false trouble codes, or over-eager field returns. Quality engineers, depot managers, and product teams track NFF to separate true hardware failures from returns that should have been resolved by support or documentation. A rising NFF rate quietly erodes margin while masking how reliable the product actually is.

What this calculator does

Measure the share of returned electronics that pass diagnostics with no confirmed defect, helping quantify avoidable RMA volume and customer support burden.
Use it when no-fault-found rate in electronics repair, refurbishment and depot operations needs a clean rate and gap-to-target you can put on a tier board.
It computes the percentage of diagnosed RMA units that were returned but had no reproducible fault, then shows the gap to your target rate.

Formula used

No-fault-found rate = no-fault-found RMA units ÷ total diagnosed RMA units × 100
No-fault-found gap to target = no-fault-found rate - target no-fault-found rate

Inputs explained

Units returned with no fault found:
Total diagnosed RMA units:
Target no-fault-found rate:

How to use the result

Use it in monthly quality reviews, when evaluating a product family's return drivers, or when building a case to improve field support and documentation.
NFF rate depends entirely on test coverage; a weak test station will under-report true NFF because it misses intermittent and marginal failures that a customer experienced in the field.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
U.S. manufacturing runs at 75.6% of capacity (Federal Reserve, May 2026). New factory orders are up 2.3% year over year (Census).
The U.S. has 11,261 computer and electronic products establishments employing about 815,443 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate no-fault-found rate? Divide no-fault-found units by total diagnosed units and multiply by 100. With 8 NFF units out of 250 diagnosed, the rate is 3.2%.
What is a good no-fault-found rate for electronics? It varies by product, but mature consumer electronics depots often see 10-30% NFF, and best-in-class programs push below 10%. The 3.2% in this example is excellent and suggests genuine failures dominate the return stream.
Why is no-fault-found rate so costly? Each NFF unit incurs inbound and outbound shipping, intake admin, and full diagnostic bench time but generates no repair value. A high rate means you are paying full process cost to confirm nothing is wrong.
What causes a high NFF rate? Common drivers are confusing user setup, false or overly sensitive trouble codes, lenient field return policies, and intermittent faults your test station cannot reproduce. The root cause is usually upstream of the depot.
How is the gap to target interpreted here? The gap is your actual rate minus the target. With a 3.2% rate against a 95% target field, the displayed gap is 91.8 points; in practice you want NFF far below such a high reference, so read the gap in the direction that matches how your target was defined.

Last reviewed 2026-05-12.