The £100k childcare cliff — priced, with the way back under

Between £100,000 and £125,140 every pound bears ~60% tax as the personal allowance tapers away. For parents of young children it's far worse: at £100,001 of adjusted net income the free childcare hours and Tax-Free Childcare vanish entirely — a cliff, not a taper, often worth £10,000–£15,000 a year. This calculator prices both on the Hundred Summers app's own tax bands, and shows the pension contribution that restores everything. Your figures never leave your browser.

Why this is the worst-designed cliff in UK finance

Cliffs punish the pound, not the income. A parent on £99,999 with two nursery-age children keeps support worth perhaps £15,000; at £100,001 it is all gone — an effective marginal rate on those two pounds measured in the hundreds of thousands of percent. The test is each parent's adjusted net income separately: a household on £99k + £99k keeps everything, a single earner on £101k loses it all. No taper, no phase-out, no appeal.

The escape is mechanical: adjusted net income is income minus gross pension contributions (and Gift Aid), so contributions duck back under the line and reclaim tax and support at once. Bonus years are the danger — a one-off bonus can cost more in lost support than it pays — and salary sacrifice adds NI savings on top of what this page shows. The full Hundred Summers plan models the 60% zone in every projected year, and the cliff guide covers the edge cases: which parent counts, when eligibility is reconfirmed, and the bonus-sacrifice playbook.