What you claim for your children, what the High Income Child Benefit Charge takes back as the higher partner's income crosses £60,000, and the pension contribution that would restore the lot. The same functions the Hundred Summers engine applies in every projected year. Your figures never leave your browser.
Loading the calculator… (requires JavaScript; your figures never leave your browser)
The charge looks only at the higher partner's adjusted net income: a household with two £59,999 earners keeps every penny while a single £81,000 earner loses it all — long criticised, still the law. Inside the £60,000–£80,000 taper, losing 1% of the benefit per £200 adds a hidden marginal rate: for a three-child family it's roughly 12 extra percentage points on top of 40% tax and 2% NI.
The fix is the same lever as every other taper: pension contributions reduce adjusted net income pound for pound, so a contribution back to £60,000 earns 40%+ relief and restores the benefit. And whatever the income: claim (at zero rate if need be) — the claim itself earns NI credits toward a non-working parent's State Pension record. The full Hundred Summers plan applies the charge in every year it bites.