A free UK calculator that gives you the real range — £92,000 to £437,000 over 18 years after Child Benefit, HICBC clawback and Tax-Free Childcare are factored in. Models up to six children at different ages, anchored on the Child Poverty Action Group's Cost of a Child report, with optional JISA parallel projection so you can see what a parallel investment for them would build by 18.
The total cost is built from two transparent components, both configurable:
| Component | Annual amount | Applies ages |
|---|---|---|
| Living base (food, clothes, equipment, activities, holidays) | £5,000 | 0–17 |
| Childcare — Family / WFH | £500 | 0–4 |
| Childcare — Part-time formal | £4,500 | 0–4 |
| Childcare — Full-time formal (post free-hours) | £9,000 | 0–4 |
| Private secondary (ISC 2025 day-school avg + 20% VAT) | £21,546 | 11–17 |
| Private throughout (ISC 2025 day-school avg + 20% VAT) | £21,546 | 4–17 |
Custom childcare is the one input that works at the household level — you type your total monthly childcare bill across all kids in nursery/care, and the calc splits it internally across the children currently in the 0–4 window. So £500/mo with 2 kids in nursery = £500 household childcare, not £500 × 2. Bounds scale with your number of children: £100/child to £5,000/child per month.
| Mechanism | 2026/27 rate | Notes |
|---|---|---|
| Child Benefit — eldest or only child | £27.05/wk | £1,406.60/yr per household with at least one child under 18. |
| Child Benefit — each additional child | £17.90/wk | £930.80/yr per additional under-18. |
| HICBC clawback | £60k – £80k | 1% of CB clawed back per £200 of highest-earner adjusted net income above £60k. Full clawback at £80k+. (Apr 2024 reform, unchanged for 2026/27.) |
| Tax-Free Childcare top-up | 20% / £2,000 cap | HMRC adds £2 for every £8 you contribute to a TFC account, up to £2,000/yr per child under 12. Stacks with the 30 free hours. |
Each child can be set to a different current age (0–17). The calculator runs all children in parallel year-by-year, so a household with one toddler and one teenager sees the correct overlap of high-cost early years for the youngest with the lower-cost school years for the elder. The Child Benefit calculation correctly applies the eldest rate to whichever child remains under 18 in any given year.
If you toggle "Show JISA parallel projection," the tool calculates the future value at age 18 of a regular monthly contribution into a Junior ISA for each child, capped at the 2026/27 allowance of £9,000/yr per child (HMRC, frozen until 2030/31). Default assumes 7% annual return — adjust to your own assumption. This is the wealth-equivalent comparison, not a recommendation to invest instead of caring for your kids.
Gross = Σ (per-child annual cost across all under-18s for each year)
Net = Gross − TFC top-up − (Child Benefit − HICBC clawback)
JISA value at 18 = FV of monthly contribution per child, compounded at chosen rate
Housing (an extra bedroom typically costs £2,000–£8,000/year — varies enormously by region), university support (most UK families use student loans plus optional top-up), and post-18 living-at-home costs. Cost figures are in nominal 2026/27 prices — not inflation-adjusted forward. Universal Credit, Healthy Start vouchers, free school meals, and Scottish/Welsh devolved childcare entitlements vary by household and aren't modelled here — for a comprehensive household projection that includes them, use WealthR in-app.
The widely-quoted £166,000 figure from CPAG's Cost of a Child report is real, but it's one specific scenario — a couple household, including rent and childcare (CPAG's 2025 report puts it at £250,000). This calculator leaves housing out, so its figures sit below CPAG's. Here's how the choices you control move the total:
The variance is dominated by two choices — childcare and education. Get those right and the rest of the cost is reasonably stable across families.