Saving for House Calculator

The Deposit Math

A 400,000 home at 10% deposit requires 40,000 saved. With 5,000 already saved at 4% return, growing to roughly 6,700 in 5 years, the gap is 33,300. Saving that over 60 months at 4% return requires about 500/month. Shorter timelines or bigger deposits raise the required monthly amount steeply.

Deposit Percent Choices

5% deposit (first-time buyer products): often available via shared-ownership and similar low-deposit schemes. 10% deposit: broadest lender availability. 15-20% deposit: access to lower rates and larger loan-to-value. Each tier changes both the saving requirement and subsequent mortgage rate.

Factors Outside the Calculator

Mortgage fees (1,000-2,500), legal fees (1,500-3,000), surveys (400-1,500), Stamp Duty (variable), and moving costs add 5,000-15,000 of additional cash needed. A conservative target adds 10-15% to the deposit figure to cover these. The calculator handles deposit only; budget separately for the rest.

Run it with sensible defaults

Using target house price of 400,000, deposit percent of 10, current savings toward deposit of 5,000, years until purchase of 5, the calculation works out to approx 504/mo. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Target House Price, Deposit Percent, Current Savings Toward Deposit, Years Until Purchase, and Savings Account Rate — do not pull with equal force. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

How the math works

Deposit target equals house price times deposit percent. Future value of current savings at purchase date calculated. Gap divided by annuity factor yields monthly savings required. Results are estimates for illustration purposes only.

Turning the result into a plan

A projection is just a starting point. The real work is setting the monthly amount aside automatically so the saving happens before you can spend it. Most people who hit savings goals set up a standing order on payday; most who miss them rely on willpower at month-end.

What this doesn't capture

The calculation assumes a steady savings rate and a stable interest rate. Real saving journeys include emergencies, windfalls, and rate changes — especially in easy-access products. The figure is a direction of travel, not a guarantee.