Methodology & Sources

Results are not estimated in your browser: your inputs are sent to the calculation engine on the server and evaluated with the formula of the tool's published version.

• Explicit formula definitions: every tool is written as a readable, step-by-step calculation definition (addition, multiplication, percentages, brackets, date differences…) instead of hidden code. The same definition produces the same result on the website, in the embeddable widget and in the public API.
• Decimal arithmetic: amounts are calculated with decimal numbers instead of binary floating point, so there is no cent drift in cases such as 0.1 + 0.2.
• Explicit rounding: money amounts are rounded half-up to the cent unless a legal rule says otherwise. When parts must add up to a total, the last part is derived by subtraction so subtotals and totals always agree.
• Clear error states: division by zero, an undefined logarithm or an interest equation without a solution produce an explanatory message instead of a random number.

Tax rates, income tax brackets, exemption amounts, fees, the minimum wage and the social security floor and ceiling are not hard-coded into tools; they are kept as separate parameters. For every parameter the following is recorded:

• the law, article or decision it is based on,
• a link to the official source (Official Gazette, Turkish Revenue Administration, mevzuat.gov.tr, SGK, the Central Bank or the responsible ministry),
• the effective start and, if any, end date,
• when the value was last reviewed.

This information is shown on every tool page under Sources and rates. A value that cannot be verified against an official source is not published, and a tool that needs it stays offline until it is. Values that legitimately differ per case (a product's special consumption tax rate, an exchange rate or a bank's offered interest rate) are inputs you enter, and the field help says so.

Before a new version of a tool goes live it passes an automatic chain of checks:

1. Test cases: every tool is verified against examples calculated by hand, independently of the formula (normal cases, boundary values and rounding cases). If a single case does not return the expected result, the version cannot be published.
2. Schema and content checks: input limits, required fields, labels in both languages, descriptions and link safety are validated.
3. Version history: every published change is stored as a new version; the Version and Last updated details on the page show which definition is running.

Tools also go through a regular quality audit that measures whether the description contains the formula and a worked example, whether results are interpreted, whether the FAQ is sufficient and whether related tools are linked.

Many Turkish amounts are revalued every year. Therefore:

• yearly values such as income tax brackets, exemptions and fees are added with their new period at the start of each year;
• the minimum wage, the social security contribution base floor and ceiling and the meal and transport exemptions are updated when the new period starts; the severance pay ceiling changes twice a year (January and July);
• for time-bound values the value valid on the calculation date is used. If no value is defined for a date, the tool says so instead of silently using an old value.

In date-based tools "today" is always the date you enter, so results never depend on the server clock.

Tools model the general rule of a calculation. Special exemptions, reductions and sector- or person-specific conditions are listed separately in each tool's warnings and Notes sections.

Results are for information only and do not replace advice from an accountant, lawyer, social security expert or doctor. Confirm the result with official sources and a professional before a tax return, a contract, a compensation claim or a health decision. Health tools produce estimates based on widely accepted formulas and are not medical advice.

If you believe a result, rate or explanation is wrong, use the contact page and include the tool name, your inputs and the result you expected. Every report is compared with the official source; if the error is confirmed, the formula or rate is fixed, a new test case is added for the missed situation and the fix is published as a new version.

The values you enter are processed only to produce the result; they are not linked to your identity and are not stored as a calculation history. To improve the service only anonymous daily counters per tool are kept (how many calculations ran, whether they succeeded, response time). Cookies and advertising are covered in the Privacy Policy.