This guide explains assumptions, formula flow, and interpretation steps so your result is reliable for planning decisions.
Use accurate, current values and keep units consistent. Where rates or thresholds change by tax year, check that your selected period matches the scenario you are testing.
The calculator validates inputs, applies the selected rules in order, and then computes intermediate totals before producing the final output. Run at least two scenarios to stress-test your decision.
Treat the output as a practical estimate. For legal, tax, payroll, or lending decisions, verify with official sources and your own records before acting.