CALCULATE THIS
How we calculate
A plain-English explanation of how Calculate This approaches formulas, assumptions and calculator quality.
Formulas first
Each calculator is built around an explicit formula or defined calculation method. Results are generated in the browser from the values you enter; we avoid hiding the basic logic behind vague scores or unexplained outputs.
Assumptions matter
Some calculations require assumptions. Mortgage projections can assume a constant interest rate, paint estimates depend on coverage, and health equations are estimates rather than direct measurements. Relevant assumptions are explained on the calculator page.
Rules that can change
Calculators affected by tax bands, government rules or other changing thresholds need extra care. Those tools should be checked against an appropriate primary source when they are created or materially updated.
Rounding
Calculations may use more precision internally than is displayed. Results are rounded to a sensible number of decimal places or currency units so they remain readable.
Not professional advice
Calculate This provides informational tools, not financial, tax, legal or medical advice. For decisions where accuracy has significant consequences, verify the result against the relevant official guidance or a qualified professional.