Accurate by design, verifiable by you
A profit calculator is only useful if you can trust it. Here is exactly how Munavo earns that — no claims you can't check.
v3.0.0
Calculation engine version — every change is versioned and documented.
300+
Automated tests run on every change, including tier boundaries and penny-rounding edges.
18 Aug 2026
UK eBay rate card last verified by hand against ebay.co.uk's published fees.
18 Aug 2026
UK Shopify rate card last verified against Shopify's published pricing.
Pinned
Saved calculations keep the rates they were made with — a rate change never silently rewrites your history.
Ex-VAT
Profit is ex-VAT revenue minus ex-VAT costs. VAT is cashflow and is reported separately, never mixed in.
Where the rates come from
Every fee number lives in a versioned rate card — nothing is hardcoded into the app. Cards are checked by hand against the platforms' own published fee pages, stamped with the date of that check, and given a review-by date. When a card is past review, the Rate Centre says so openly instead of pretending.
How the engine is tested
The calculation engine is covered by an automated test suite that runs before every release: golden reference cases, VAT edge cases (exports, non-registered sellers, EU imports), fee tier boundaries and penny-fraction rounding. The full calculation method is written up in a versioned specification the tests are built against, and the worked example on the homepage is generated by the engine itself — a test fails if the marketing numbers ever disagree with the maths.
What happens when rates change
Saved calculations pin the rate card they were made with. When platforms change their fees, your history stays exactly as it was — and the app offers current rates as an explicit, visible choice.
What we don't promise
Munavo produces estimates for guidance, not financial advice. Your own account can carry negotiated rates, promotions or penalties we can't see. If a number ever looks wrong, tell us — being correctable in public is the point.