Clear methods
Honest assumptions

A result is useful when you know what went into it. Each calculator explains its method and provides a worked example you can reproduce.

How results are calculated

The computation is separate from the interface and display formatting. Money formulas use decimal arithmetic where needed. The small-matrix tools use bounded exact rational arithmetic; most other calculations use standard browser numerical arithmetic. Display rounding does not change an underlying calculation unless the method explicitly requires it.

What we check

The local build checks known example results, input validation, relevant boundary cases and relationships between related values. Shared page templates provide consistent labels, units and result handling. Each specialist calculator still needs its own method review; sharing a template alone does not prove accuracy.

Different tools, different limits

Investment growth uses assumed returns, not predictions. Loan estimates can differ from a lender's quote because of fees, payment dates and rounding. Health estimates are screening information, not diagnoses. Unit converters distinguish measurement systems, such as US and imperial gallons.

Rules and references

Where a tool relies on an external standard, the reference is linked on its page. Tools requiring changing tax rules or statutory thresholds need a named jurisdiction and effective year before release. A GST arithmetic tool uses the rate you enter; it does not decide which rate applies to a transaction.

Spot something unexpected?

Keep the calculator name, entered units, expected result and a reliable reference when reporting an issue. Avoid including private financial or medical details. See our contact information.