UK Mortgage Calculators
Free, mobile-friendly calculators for every stage of the mortgage journey — using current 2026 UK tax bands and lender rules.
TL;DR
Pick a calculator below. Each one shows the full breakdown of how the result is worked out, with the assumptions used and the date they were last updated.Buying
- Stamp DutySDLT, LBTT, LTT — all variants.
- AffordabilityHow much you can borrow.
- Mortgage repaymentComing soonMonthly cost & total interest.
- Buy vs rentCompare monthly cost of owning and renting.
- First-time buyerComing soonAffordability + SDLT + deposit combined.
- Deposit savings goalComing soonHow long to save your deposit.
Investment
- Buy-to-letComing soonMortgage cost, yield, stress test.
- BTL stress test (ICR)Coming soonLender ICR rules.
- Rental yieldComing soonGross & net yield.
- Holiday letComing soonFHL income & costs.
Existing owners
- OverpaymentComing soonSave interest, shorten term.
- RemortgageComing soonLTV, fees, rate switch.
- Interest-onlyComing soonMonthly cost vs repayment.
- Equity releaseComing soonLifetime mortgage estimate.
- Early repayment chargeComing soonCost of leaving your deal early.
Specialist
- Self-buildComing soonStage payments & costs.
- Bridging loanComing soonShort-term finance cost.
- Let-to-buyComing soonLetting current home & buying new.
- Joint borrower sole proprietorComing soonBoost borrowing with a guarantor.
Why use Mortgage118 calculators?
Every calculator is built around current UK rules — SDLT bands, LBTT and LTT thresholds, lender stress test rates and FCA-aligned affordability multiples. Each result page shows its assumptions and the date they were last updated, so you always know exactly what's behind the number.