New Build Mortgage Calculator: How Lenders Treat Your Incentive Package
Based on verified new-build lending criteria (verified 2026-08-19), see how each of the 10 lenders we track treats deposit contributions, cashback, paid stamp duty and legal fees, and non-cash upgrades — and what it means for your maximum loan and minimum buyer deposit.
This is an information tool, not advice: it doesn't give a recommendation, a decision in principle, or a guarantee any lender will lend to you.
Worked example: £350,000 house, £25,000 builder deposit contribution
No cashback, stamp duty or legal fees paid — just a £25,000 cash gift toward the deposit, which is 7.1% of price.
4 of the 10 lenders we track decline this package outright — Nationwide, Santander, Skipton, Perenna — because it exceeds their hard cap on incentives as a share of price.
- Halifax: 95% LTV, up to £307,500 loan, £17,500 needed from you — Builder incentive reduces the maximum loan under Halifax's 95% mortgage-plus-incentive gate — effective maximum ~87% of price after the incentive gate
- NatWest: 95% LTV, up to £325,300 loan, £17,500 needed from you — A builder deposit contribution must supplement your own deposit, not replace it — a minimum of 5% of price must come from you
- Barclays: 90% LTV, up to £308,200 loan, £41,800 needed from you — Any incentive caps Barclays' new-build LTV at 90%
Change the inputs below to model your own numbers.
Same £15,000 deposit contribution, but with part-exchange
£300,000 house, buyer part-exchanges their current home AND takes a £15,000 builder deposit contribution.
Combining part-exchange with a cash incentive is a common trap: HSBC declines the case outright — part- exchange already counts as the full incentive allowance, so adding cash on top pushes it over. NatWest still lends at 95% LTV, up to £285,000.
Change the inputs below to model your own numbers.
Between £50,000 and £5,000,000.
Which mortgage lenders accept new-build incentives above 5%?
Very few, and none without an adjustment. In our verified dataset of 10 new-build lenders (checked 2026-08-19), a package worth 7.1% of the price is declined outright by 4 lenders (Nationwide, Santander, Skipton, Perenna). The lenders that will still consider the case — Halifax, NatWest, Barclays, HSBC, Accord, Virgin Money— do it by reducing the maximum LTV or deducting the incentive from the value they lend against, so the buyer's own deposit requirement rises rather than disappearing. The industry-standard UK Finance Disclosure of Incentives Form means the valuer and lender always see the full package, so under-declaring is not a strategy. Run your own package through the calculator above for the lender-by-lender outcome.
FAQ
What counts as an "incentive" that lenders assess?
Anything the builder gives you that reduces what you actually pay or funds your deposit: a cash deposit contribution, cashback after completion, paid stamp duty or legal fees, part-exchange of your current home, and non-cash extras like a fitted kitchen or flooring upgrade. Lenders treat cash-equivalent incentives (the first four) far more strictly than non-cash upgrades.
Why do some lenders decline a package outright?
Most lenders cap total cash incentives at around 5% of price before they either reduce your maximum LTV or deduct the excess from the property's value for lending purposes — a handful (Nationwide, Skipton, Perenna, Santander in our dataset) decline the application entirely once incentives cross that line, rather than adjusting the numbers.
Worried about the valuation? Stress-test a down-valuation →