Project your savings growth towards a house deposit, with optional Lifetime ISA bonus for first-time buyers.
This calculator provides estimates only. Interest rates and LISA bonus rules may change. The LISA is only available to first-time buyers purchasing property up to GBP 450,000. Withdrawing LISA funds for non-qualifying purposes incurs a 25% withdrawal charge. Consult a financial adviser for personalised guidance.
Saving for a house deposit is one of the biggest financial goals most people face. With UK property prices averaging around GBP 290,000 nationally and significantly more in London and the South East, even a 10% deposit requires substantial savings. This calculator projects how long it will take to reach your target based on your monthly contributions and interest rate, with the option to include the powerful 25% Lifetime ISA (LISA) government bonus for first-time buyers. The calculator models your savings month by month, applying compound interest and any LISA bonuses to show a realistic projection. It accounts for the LISA annual contribution cap of GBP 4,000 and the maximum government bonus of GBP 1,000 per year. Whether you are just starting to save or already have money set aside, this tool helps you visualise the path to your deposit and understand how different savings strategies affect the timeline.
To project your deposit savings: 1. Enter your target deposit amount. This is the total deposit you need for your property purchase. For example, a 10% deposit on a GBP 250,000 property would be GBP 25,000. Check with mortgage lenders for their minimum deposit requirements. 2. Enter your current savings. If you already have money saved towards your deposit, enter the amount here. This becomes the starting point for the projection and reduces the time to reach your target. 3. Enter your monthly saving amount. This is how much you can realistically set aside each month towards your deposit. Be honest with this figure to get an accurate projection. Even small increases in monthly savings can significantly reduce the time to reach your target. 4. Set the annual interest rate. Enter the interest rate you expect to earn on your savings. Cash ISA rates in 2026 typically range from 3% to 5%. The default of 4% represents a reasonable mid-range estimate for a competitive savings account. 5. Toggle the Lifetime ISA option. If you are a first-time buyer aged 18-39, consider enabling the LISA option to see how the 25% government bonus accelerates your savings. The calculator automatically caps LISA contributions at GBP 4,000 per year. 6. Review the timeline. The results show the number of months and years to reach your target, total contributions, interest earned, and any LISA bonus. The line chart visualises your savings growth over time.
The deposit savings projection uses a month-by-month compound interest model. Each month, your contribution is added to the balance, any applicable LISA bonus is added, and then interest is calculated on the total balance. The monthly interest rate is the annual rate divided by 12. For a 4% annual rate, the monthly rate is approximately 0.333%. Interest compounds each month, meaning you earn interest on previously earned interest. For LISA calculations, the monthly contribution that goes into the LISA is capped at approximately GBP 333.33 (GBP 4,000 annual limit divided by 12). The government adds a 25% bonus on LISA contributions, up to GBP 1,000 per year. If your monthly saving exceeds the LISA monthly limit, only the LISA-eligible portion receives the bonus -- the remainder still earns interest but without the government top-up. The calculator tracks annual boundaries to reset the LISA contribution limit each year. This means in the first year you can contribute up to GBP 4,000 to the LISA (receiving up to GBP 1,000 bonus), and the same in each subsequent year. The projection continues until the balance reaches or exceeds the target deposit, or until a maximum of 50 years (600 months). The chart shows savings growth at quarterly intervals for a clear visual representation.
The Lifetime ISA is one of the most generous savings incentives available to UK first-time buyers. The 25% government bonus is effectively free money, and because the bonus itself earns compound interest in subsequent months, the real value over time exceeds the headline figures. However, the LISA has important restrictions. It is only available to those aged 18-39 to open (you can continue contributing until age 50). The property must cost GBP 450,000 or less. You must have held the LISA for at least 12 months before using it for a property purchase. Withdrawing funds for any purpose other than buying your first home or after age 60 incurs a 25% government withdrawal charge, which means you lose your bonus and approximately 6.25% of your own contributions. The ISA annual allowance for 2026-27 is GBP 20,000 across all ISA types. Your LISA contribution (up to GBP 4,000) counts towards this total. You can hold both a LISA and other ISAs in the same tax year, as long as your total contributions do not exceed GBP 20,000. When choosing where to save, consider the interest rate, access to funds, and any bonus schemes. High-interest regular saver accounts sometimes offer rates above standard savings accounts but may limit monthly deposits. Fixed-rate savings bonds offer higher rates but lock your money away for a set period. First-time buyers in England and Northern Ireland also benefit from stamp duty relief on the first GBP 300,000 of properties up to GBP 500,000, saving up to GBP 5,000. This is separate from the LISA and can be claimed alongside it. Remember that property purchases involve additional costs beyond the deposit. Budget for solicitor fees (GBP 1,000-2,000), survey costs (GBP 300-1,500), mortgage arrangement fees (GBP 0-2,000), and moving costs. It is wise to have 3-6 months of expenses in an emergency fund alongside your deposit savings.