Written about how things work rather than what they currently cost. A mechanism does not change in April; a figure does, and figures live on the calculators, where every page states its tax year and the date a person last checked it against the source.
How it actually works.
The calculators give you a number. These explain the mechanism behind it — how the deductions stack up, why a threshold produces an effect nobody advertises, and what the rules are doing when the arithmetic looks wrong.
- Why your first Self Assessment bill is bigger than you expected Payments on account mean the first profitable January costs about half again as much as the tax you owe — not a penalty, not an error, and the most common self-employed cash-flow shock.
- How take-home pay is actually calculated The full deduction stack, in the order it happens — why the bands are narrower than the headline rates suggest, and why a pay rise sometimes leaves you with less than you expected.