Methodology
Updated: 6 September 2026
Trust in a calculator starts with knowing HOW it calculates. This page explains how we implement formulas, where our official rates come from and what we do when regulations change.
Formulas are public and tested
Every calculator on the site is implemented as pure mathematical logic, separated from the page layout. That logic is covered by automated unit tests with hand-verified examples: before a calculator is published, we work an example out by hand (or verify it against a trusted source) and the test guarantees the code always produces the same result. The tests run on every change to the site.
The formula each calculator uses is shown on the calculator page itself, in the "How it works" section, together with an example. Nothing is a black box — you can verify every result by hand.
Official rates: official sources only
Tax and legal rates (e.g. contribution and income-tax rates in the gross-net salary calculator) come exclusively from official sources — for each market, from that market's own official institutions. For the Bosnian edition these are the Tax Administration of the Federation of BiH, the Tax Administration of Republika Srpska and the official gazettes in which regulations are published; today only the Bosnian edition's salary rates are implemented, and Croatian and Serbian figures will arrive with their own verified sources. We never copy rates from other calculators or portals.
For every rate we record: the exact figure, the date it applies from, the source it was taken from and the date we last verified it. The source and verification date are shown to the user directly on the calculator page. Before any rate change we re-verify it in the official source — an unverified rate is never published.
You can see this approach in practice on the gross-net salary calculator, which shows the current FBiH and RS rates together with their sources.
Exchange rates
BAM ↔ EUR conversion uses the fixed rate of 1 EUR = 1.95583 KM, established by the currency-board arrangement of the Central Bank of Bosnia and Herzegovina. This rate is fixed by law, so the conversion works even offline.
Rates for other currencies (USD, RSD, GBP, CHF...) come from an independent third-party exchange-rate service and are refreshed periodically; the date the rate refers to is always shown next to the result. These are indicative mid-market rates — banks and exchange offices apply their own buy/sell rates.
Rounding conventions
In the loan calculator the installment is rounded to two decimals and the final installment is adjusted to repay the exact remaining balance (standard banking practice that prevents cents from being "lost" to rounding). For work tenure we use the regional pension convention: both boundary days count and months are counted as 30 days, so the period 01.01–31.12 equals exactly one year. These conventions are also explained on the calculator pages themselves.
Corrections and error reports
If you find a result that looks wrong, report it via the Contact page — ideally with the "share" link that contains the values you entered. We check every report against the formula and the source; confirmed errors are fixed with priority, and the fix comes with an updated test so the same error cannot recur.