Every example at a glance
6 scenarios, all worked the same way. Tap a row to jump to the full breakdown.
| Purchase & deposit | Monthly | Borrowed | Total interest |
|---|---|---|---|
| £200,000, £20,000 deposit | £1,000.50 | £180,000 | £120,150 |
| £250,000, £25,000 deposit | £1,250.62 | £225,000 | £150,187 |
| £300,000, £30,000 deposit | £1,500.75 | £270,000 | £180,224 |
| £300,000, £60,000 deposit | £1,334.00 | £240,000 | £160,199 |
| £400,000, £80,000 deposit | £1,778.66 | £320,000 | £213,599 |
| £500,000, £125,000 deposit | £2,084.37 | £375,000 | £250,312 |
How it is worked out
A repayment mortgage uses the same annuity formula as any other fixed-rate loan, applied to the amount borrowed rather than the purchase price:
- P — the amount borrowed: purchase price minus deposit
- r — the monthly rate: 4.5% ÷ 12 = 0.00375
- n — 25 × 12 = 300 payments
Loan-to-value is the amount borrowed as a percentage of the price, and it is the number lenders price against. It matters in steps, not smoothly: the rate you are offered typically improves at 90%, 85%, 80%, 75% and 60% LTV, and a deposit that lands just the wrong side of a boundary costs more than the missing money is worth.
Each example in full
Every card below opens in the Mortgage Calculator with its own numbers already filled in, so you can change one figure and see what moves.
£200,000, £20,000 deposit
£200,000 with a 10% deposit is the shape of a typical first purchase outside the South East, and it sits exactly on the 90% LTV rung where lender pricing changes.
Open this one in the Mortgage Calculator →£250,000, £25,000 deposit
£250,000 at 90% LTV is close to the UK average purchase, and it is the price at which the gap between a 10% and a 15% deposit starts being worth several thousand pounds.
Open this one in the Mortgage Calculator →£300,000, £30,000 deposit
£300,000 with £30,000 down is the most-searched mortgage combination of the set, and the clearest illustration of how little of the early payment touches the capital.
Open this one in the Mortgage Calculator →£300,000, £60,000 deposit
The same £300,000 property at 80% LTV. Comparing this page with the 10%-deposit one shows what doubling the deposit buys before any rate improvement is counted.
Open this one in the Mortgage Calculator →£400,000, £80,000 deposit
£400,000 at 80% LTV is around the average price of a house sold in England, and the point where a half-point rate difference passes £100 a month.
Open this one in the Mortgage Calculator →£500,000, £125,000 deposit
£500,000 at 75% LTV reaches the band where most lenders stop discounting further, so extra deposit above this point buys a smaller loan rather than a better rate.
Open this one in the Mortgage Calculator →What these figures do not include
- The rate itself. 4.5% is held constant across every row so the deposit effect is visible in isolation — in reality a 75% LTV case would usually be offered a better rate than a 90% one, widening the gap further.
- Product, arrangement and valuation fees, and whether a fee is paid up front or added to the loan.
- Stamp duty, conveyancing, survey and moving costs, none of which are part of the mortgage.
- What happens after the initial fixed period ends, when the loan usually reverts to a higher variable rate.
- Whether the lender would approve the borrowing at all, which depends on income multiples and affordability testing rather than LTV alone.
Frequently asked questions
How much does a bigger deposit actually save?+
Compare the two £300,000 rows: a £30,000 deposit (90% LTV) costs £1,500.75 a month and £180,224 in interest, while a £60,000 deposit (80% LTV) costs £1,334.00 and £160,199. The extra £30,000 of deposit saves £166.75 a month and £20,025 of interest — before any rate improvement the lower LTV would usually also earn.
Why is every example at 4.5% over 25 years?+
So that the deposit is the only thing changing. Holding the rate and term constant isolates the effect of loan-to-value; use the calculator link on any row to substitute the rate and term you have actually been offered.
Is loan-to-value the only thing lenders price on?+
No. LTV sets the tier of products you can reach, but income, credit history, property type and whether the lending is for a first home, a move or a buy-to-let all affect the rate within that tier.