Cost of Quality Calculator
Total prevention, appraisal, internal and external failure costs.
In short
Total prevention, appraisal, internal and external failure costs.
Formula: CoQ = (Prevention + Appraisal) + (Internal failure + External failure)
What this calculator does
Addition within the four named categories, with the conformance and non-conformance subtotals and each category's share of the total.
Use it to turn Currency, Prevention costs (optional), Appraisal costs (optional), Internal failure costs (optional), and the other shown inputs into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this professional & industry calculation.
Inputs and what they mean
- Currency
- — Amounts are shown in the currency you pick. No exchange rate is applied..
- Prevention costs (optional)
- — Optional. Leave at 0 to exclude it from the result. Training, planning, process control, supplier development..
- Appraisal costs (optional)
- — Optional. Leave at 0 to exclude it from the result. Inspection, testing, audits, calibration..
- Internal failure costs (optional)
- — Optional. Leave at 0 to exclude it from the result. Scrap, rework, re-testing, downgrading — found before delivery..
- External failure costs (optional)
- — Optional. Leave at 0 to exclude it from the result. Warranty, returns, recalls, complaint handling — found after delivery..
- Revenue for the same period (optional)
- — Optional. Leave at 0 to exclude it from the result. Used only to express the total as a share of revenue..
How to use it
- Enter your own figures — the calculator never fills in a rate, price or benchmark for you.
- Press Calculate to see the result.
- Read the formula, variables, assumptions and source below the result before you rely on it.
Formula
CoQ = (Prevention + Appraisal) + (Internal failure + External failure).
Inputs used: Currency, Prevention costs (optional), Appraisal costs (optional), Internal failure costs (optional), External failure costs (optional), Revenue for the same period (optional).
Edge handling: Prevention costs (optional) is required.; Prevention costs (optional) cannot be negative.; Prevention costs (optional) must be no more than 1000000000000.; Appraisal costs (optional) is required.; Appraisal costs (optional) cannot be negative..
Worked example
Four categories recorded for one quarter
- Start with Currency: USD, Prevention costs (optional): 42000, Appraisal costs (optional): 68000, Internal failure costs (optional): 115000, External failure costs (optional): 84000, Revenue for the same period (optional): 6200000.
- Apply the method: CoQ = (Prevention + Appraisal) + (Internal failure + External failure).
- Conformance and non-conformance are totalled separately.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Inputs outside the supported range are rejected rather than forced into a result.
- The result depends on the values you enter for this cost of quality calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: American Society for Quality — Cost of quality — prevention, appraisal and failure costs
Last reviewed:
Common questions
Where does this formula come from?
ASQ cost of quality: quality costs are grouped as prevention, appraisal, internal failure and external failure. See the source link on this page.
What kind of calculation is this?
The prevention-appraisal-failure model: conformance costs plus non-conformance costs, each category reported separately. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
What are its limits?
Only the costs entered are included; costs not recorded by the organisation are absent from the total. Category boundaries vary between organisations, which limits comparison with anyone else's figures. A measured cost of quality, an industry benchmark and an organisation's target are three different things.
How do I use the Cost of Quality Calculator?
Enter the required values for Currency, Prevention costs (optional), Appraisal costs (optional), Internal failure costs (optional), External failure costs (optional), and the other fields shown. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the Cost of Quality Calculator use?
CoQ = (Prevention + Appraisal) + (Internal failure + External failure) The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
Can the Cost of Quality Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
Formula, source and verification
The prevention-appraisal-failure model: conformance costs plus non-conformance costs, each category reported separately.
The question it answers: What are we spending on quality, and how much of it is spent on things going wrong?
The formula
CoQ = (Prevention + Appraisal) + (Internal failure + External failure)
- P — Prevention
- (currency). Training, planning, process control, supplier development.
- A — Appraisal
- (currency). Inspection, testing, audits, calibration.
- IF — Internal failure
- (currency). Failures found before delivery.
- EF — External failure
- (currency). Failures found after delivery.
- Rev — Revenue
- (currency). Optional. Used only to express the total as a share of revenue.
Units: Currency in; currency and percentages out, in the currency selected.
What kind of calculation this is
Deterministic formula. The same inputs always give the same answer. The maths is fixed and does not depend on judgement.
Method
Addition within the four named categories, with the conformance and non-conformance subtotals and each category's share of the total.
Assumptions built into the result
- Mathematical: Each cost has been assigned to exactly one of the four categories.
Figures this calculator will never guess for you
- No benchmark, target or 'world class' value is supplied or implied; the result describes only the figures entered.
- No share of revenue is suggested as normal or acceptable.
- No multiplier is applied for hidden or unmeasured quality costs.
- Amounts are shown in the currency selected; no exchange rate is applied.
Limitations
- Only the costs entered are included; costs not recorded by the organisation are absent from the total.
- Category boundaries vary between organisations, which limits comparison with anyone else's figures.
- A measured cost of quality, an industry benchmark and an organisation's target are three different things.
Source and version
- Standard or reference
- Cost of quality — prevention, appraisal and failure model — ASQ (ASQ cost of quality: quality costs are grouped as prevention, appraisal, internal failure and external failure.)
- Published source
- American Society for Quality — Quality resources
- Formula version
- Version 1
- Verification
- Reviewed against the cited source on
- How much weight the source carries
- Standards or government
- Applies to
- Currency
- Amounts stay in the currency you choose; no exchange rate is applied.
Cite this page
Free Calculator. (2026, September 16). Cost of Quality Calculator. https://freecalculator.tech/tools/cost-of-quality-calculator
"Cost of Quality Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/cost-of-quality-calculator.
Cost of Quality Calculator — Free Calculator, https://freecalculator.tech/tools/cost-of-quality-calculator
Related tools
Work out the hourly rate to charge a client so that target margin is met after overhead and non-billable time.
Find the true hourly cost of an employee once benefits, payroll cost and overhead are included.
Size a software application from its data and transaction functions before estimating effort or cost.
Estimate development effort, schedule and average team size for a software project of a known size.
Express cloud spend as a cost per customer, per transaction or per other business unit.
Set the rate used to apply manufacturing overhead to jobs for the coming period.