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Most lenders work from your net income after payslip deductions, subtract your committed monthly expenditure, and then run a stressed-rate affordability model on what remains. Childcare sits squarely in that "committed expenditure" bucket — and because nursery bills are often the largest single outgoing a young family has, they move the answer more than almost anything else on the form. As a rule of thumb, every £1 of committed monthly outgoing reduces maximum borrowing by roughly £40–£60, so a full-time nursery place can easily be worth a bedroom.
The good news: the impact is nowhere near uniform across the market, and there are legitimate ways to present the true picture — funded hours, costs that are about to end, and benefits that some lenders count as income.
What lenders ask about children and childcare
Every affordability calculator asks two related questions: how many dependants you have, and what you pay in childcare— nursery, childminder, nanny, after-school clubs and holiday clubs all count. The dependant count drives the lender's assumed household running costs; the childcare figure is treated as a committed monthly commitment in its own right, exactly like a loan repayment.
You must declare these honestly. Nursery payments are unmistakable on bank statements, and a mismatch between your declaration and your statements is one of the most common reasons an underwriter revisits a case. Applying the £40–£60 rule of thumb, £1,000 a month of nursery fees commonly reduces a maximum loan by £40,000–£60,000 — so this is not a field to guess at, in either direction.
Be precise about what belongs in the box, though. Childcare means the regular, committed amounts you pay for care — not toys, clothes or general family spending, which the dependant count already accounts for. If your arrangement is informal and unpaid (grandparents, a partner working opposite shifts), your declared childcare cost is genuinely £0, and at declared-cost lenders that is exactly how it should go down. Equally, don't forget costs that are committed but easy to overlook, such as breakfast clubs or a regular holiday-club pattern.
Declared costs vs modelled costs: why lenders differ
Here's where it gets interesting. Lenders split into two broad camps:
Declared-cost lendersuse the childcare figure you actually pay. If grandparents cover two days a week and your bill is £400 a month, that's what enters the model.
Modelled-cost lenders apply their own ONS-style expenditure assumptions per dependant — and some will use their modelled figure even if your real costs are lower. A family paying nothing for childcare can still see a chunky deduction per child at these lenders, simply because the model says children cost money.
The result is that the same family, same payslips, same nursery invoice can get maximum loans tens of thousands of pounds apart depending on which lender they happen to ask. On a joint application with two or three dependants, the spread widens further. No single-lender calculator can tell you whether you're looking at a generous or a punitive treatment — only comparing across the market does.
Same kids, very different answers
Free 2-minute check across 60+ UK lenders — see how YOUR outgoings change the answer at each lender.
Start My Free CheckFunded hours and Tax-Free Childcare in 2026
Government support has expanded substantially, and it feeds straight into your declarable costs. In England in 2026, working parents are entitled to 30 funded hours per week from age nine months right through to school age — the full rollout completed in September 2025. The entitlement is term-time (38 weeks), though many providers let you "stretch" it across the full year at fewer hours per week.
On top of that, Tax-Free Childcareadds a 20% government top-up on what you pay in: worth up to £2,000 per child per year (£4,000 for a disabled child). Between funded hours and the top-up, a nursery bill that would have been £1,400 a month a few years ago might now land closer to £900 — and it's that lower, post-support figure you declare. Scotland, Wales and Northern Ireland run different schemes with different ages and hours, so check the local position if you're outside England.
Practical tip: bring recent nursery invoices to an application. They evidence your true post-funding cost, which protects you at declared-cost lenders from any temptation an underwriter might have to assume a higher figure.
Costs about to fall? Some lenders will listen
Childcare costs have a built-in cliff edge: the September your child starts school, a £950 nursery bill can drop to £250 of wraparound care. If you're applying in the months before that happens, some lenders will accept evidence — a confirmed school place, a nursery notice letter — and underwrite on the lower future figurerather than today's cost.
This is not universal and rarely advertised, which is exactly the kind of situation where a broker earns their keep. The same logic applies to a parent returning from maternity leave: lenders that take a pragmatic view of return-to-work income often take a pragmatic view of transitional childcare costs too.
Child benefit can count as income
Children don't only add outgoings to the calculation — they can add income too. Child benefitand certain Universal Credit elements are counted as income by some lenders, partially offsetting the childcare deduction. The catch is the conditions: many lenders only count child benefit below a household income cap, or only while children are under a certain age, and some won't count it at all.
For a two-child family, child benefit is worth around £2,250 a year — at a lender that accepts it, that's potentially £10,000+ of borrowing recovered. Our guide to which lenders accept benefits as income covers the patterns in detail.
Worked example: £70,000 household, £950/month nursery
Here's how the same family can land in three very different places across the market.
One family, three lender outcomes
The family:
Joint income £70,000, one child in nursery at £950 per month, headline borrowing at ~4.5× income ≈ £315,000 before expenditure.
Lender A — deducts the full declared childcare:
£950/month committed cost at £40–£60 per £1 wipes £40,000–£55,000 off. Maximum loan caps nearer £265,000–£275,000.
Lender B — nets off funded hours and counts child benefit:
Underwrites on the post-funding nursery cost and adds child benefit back as income. Maximum loan lands at £290,000+.
Spread between the strictest and most generous treatment: £25,000–£30,000+ — on identical payslips and the same nursery invoice.
None of these lenders is "wrong" — they simply model family expenditure differently. But if you only ever ask one of them, you'll never know which treatment you got.
Frequently asked questions
Do I have to declare childcare costs on a mortgage application?
Yes. Lenders ask for your number of dependants and your actual childcare costs, and they cross-check against your bank statements, where nursery or childminder payments are easy to spot. Under-declaring a regular committed cost risks the application being re-underwritten or declined later, which is far worse than declaring it upfront.
Do free childcare hours reduce what I declare?
You declare what you actually pay. If funded hours have cut your nursery bill from £1,400 to £950 a month, £950 is your committed cost. Keep recent invoices handy — they evidence the post-funding figure, which matters because some lenders would otherwise apply their own modelled cost per child.
Does child benefit count as income for a mortgage?
At some lenders, yes. A number of lenders include child benefit (and certain Universal Credit elements) as income, though often only below a household income cap or while children are under a certain age. Others ignore it entirely. This is one of the biggest sources of lender-to-lender variation for families.
Will childcare costs that are ending soon be ignored?
Sometimes. If your child starts school in September and your nursery bill is about to fall sharply, some lenders will accept evidence — a school place confirmation, for example — and use the lower future figure. It is not automatic, and many lenders simply use today's cost, so it is worth raising explicitly with a broker.
Why do lenders give such different amounts once I have kids?
Because they model dependants differently. Some use your declared childcare costs; others apply their own ONS-style expenditure assumptions per dependant even if your real costs are lower; some add child benefit back as income and some don't. The same family can see maximum loans £40,000+ apart across the market.
See how your childcare costs change your results
With dependants in the picture, the spread between lenders is at its widest — declared versus modelled costs, child benefit in or out, funded hours recognised or ignored. Mortgage Affordability runs your actual household — incomes, dependants, real childcare costs and any benefits — against 60+ UK lenders at once, so you can see which end of that £25,000+ spread you're standing on before you apply anywhere.
Last updated: June 2026
