Mortgage Deposit Savings Calculator
Our mortgage deposit calculator shows how long it takes to save any deposit target at your current savings rate, and what impact different deposit sizes have on your mortgage — including rate access, Loan-to-Value ratio, and monthly payment. Saving even a slightly larger deposit can unlock significantly better mortgage rates and save thousands over the mortgage term.
Saving for a Deposit
Work out how long to save your deposit and which LTV thresholds you can reach.
Why Deposit Size Matters
Mortgage rates in the UK are tiered by Loan-to-Value (LTV). Moving from 95% LTV (5% deposit) to 90% LTV (10% deposit) typically reduces the available rate by 0.3–0.7 percentage points and significantly increases lender choice. Moving from 90% to 75% LTV (25% deposit) usually offers the best rates available. On a £250,000 mortgage, a rate improvement of 0.5% saves approximately £100 per month — £1,200 per year — more than enough to justify a larger deposit in most cases.
On a £300,000 purchase, the difference between a 5% deposit (£15,000, mortgage £285,000) and a 10% deposit (£30,000, mortgage £270,000) is £15,000 in savings. The rate improvement might take the mortgage from 4.9% to 4.4% — reducing the monthly payment by £85 and saving £5,100 over a 5-year fix. The additional £15,000 saved effectively earns an implicit return of 34% over 5 years — far better than any cash savings account.
How Long to Save Your Deposit
On average, first-time buyers in England purchase at £273,000 — requiring a minimum £13,650 deposit at 5% LTV, or £27,300 at 10%. Saving £500 per month at a 4.5% annual return takes approximately 30 months to reach £15,600 or 55 months to reach £27,300. This calculator models any target, savings rate, and interest rate to give an accurate timeline.
Frequently Asked Questions
Yes. A Lifetime ISA allows you to save up to £4,000 per year and receive a 25% government bonus (up to £1,000 per year) toward a first home purchase. The property must cost £450,000 or less and be purchased with a mortgage. The LISA must have been open for at least 12 months before use.
Many first-time buyers receive some or all of their deposit as a gift from parents or family. Most lenders accept gifted deposits provided the donor signs a declaration confirming it is a gift (not a loan) and will not need repaying. The donor may also need to provide evidence of the source of funds.
The Help to Buy equity loan scheme for England closed to new applications in March 2023. The Mortgage Guarantee Scheme (supporting 95% LTV mortgages) remains available. Scotland, Wales, and Northern Ireland have their own separate schemes with different eligibility rules.
A larger deposit demonstrates financial discipline and reduces lender risk — which can help borderline credit cases. A larger deposit also means more lenders will consider your application, increasing competition and the likelihood of a better rate.
Stamp duty must be paid from cash on completion — it cannot be borrowed as part of the mortgage. This means your total cash requirement is deposit plus SDLT plus solicitor fees. Always factor SDLT into your savings plan. Our Stamp Duty Calculator shows the exact SDLT for any purchase price and buyer type.
Enter the property price you are targeting and your current savings. Then add your monthly saving amount and the interest rate on your savings account. The calculator projects how long it will take to reach each deposit threshold: 5%, 10%, 15%, and 20%. A larger deposit reduces both the loan and the rate offered. The 85% LTV tier (15% deposit) and 80% LTV tier (20% deposit) typically offer meaningfully better rates than 90% or 95% products. The calculator also shows how house price growth — if any — affects your real position: saving hard while prices rise can mean the target keeps moving. A Lifetime ISA adds a 25% government bonus on up to £4,000 per year, which can meaningfully accelerate deposit building for first-time buyers purchasing under £450,000.
Important Information
This calculator is provided for general information and planning purposes only. It does not constitute financial or tax advice and should not be relied upon as such. Figures are indicative estimates based on simplified, publicly available criteria and stated assumptions. Actual results depend on your full circumstances. See our Disclaimer for further information.