Savings Goal Calculator
Enter your target amount, deadline, what you already have and an interest rate — see exactly how much you need to put away each month to get there. The tool does the compound-interest arithmetic for you, so the answer is a single concrete monthly figure rather than a rule of thumb.
How it works
The calculation runs the compound-interest maths in reverse: your current pot grows at the given rate, and the tool solves for the monthly deposit that closes the remaining gap by your deadline.
A useful sanity check is the zero-interest baseline: goal ÷ number of months. £20,000 over 5 years is £20,000 ÷ 60 = £333 a month before any interest; the tool's answer will always sit at or below that baseline, and how far below depends on the rate and the timeframe.
Interest does real work over longer horizons: a £20,000 goal in 5 years at 4.5% needs about £280 a month from zero — without interest it would be £333. Over short horizons (a year or two) the rate barely matters; consistency does.
A starting pot changes the answer more than most people expect, because it compounds untouched for the whole period while monthly deposits only compound from the month they are made. Even ignoring interest entirely, £5,000 already saved toward a £20,000 five-year goal cuts the requirement from £333 to (£20,000 − £5,000) ÷ 60 = £250 a month — and interest widens that gap further.
The common mistakes are the two extremes: chasing an extra fraction of a percent on a one-year goal (at that horizon the rate is nearly irrelevant — deposit size does all the work), and ignoring the rate on a ten-year goal, where compounding genuinely carries a large share of the target.
What the result does and does not include: it assumes the rate you enter is constant for the whole period and is the rate you actually keep. Interest earned outside an ISA can be taxable, so if your interest will be taxed, the after-tax rate is the honest number to enter.
Keep goals in the right wrapper: emergency funds in easy-access savings, sub-5-year goals in cash (fixed or easy-access), longer horizons possibly in a stocks & shares ISA — and remember interest outside an ISA can be taxable.
FAQ
How much do I need to save a month to reach £10,000?
Depends on time and rate: from zero at 4% interest, roughly £394/month over 2 years, £151/month over 5 years, or £68/month over 10. A starting pot cuts these sharply — enter your own numbers above and the tool solves it exactly.
Does the interest rate really matter for short-term goals?
Barely, under about two years — at £400 a month, the difference between 3% and 5% over 18 months is under £100. Time and deposit size dominate. Over 5-10 years the rate compounds into a serious contribution, which is why long-horizon goals justify chasing better rates or investment returns.
Where should I keep money I am saving toward a goal?
Match the wrapper to the horizon: instant-access for emergency funds, regular-saver or fixed-rate accounts for 1-5 year goals, and consider a stocks & shares ISA beyond 5 years (accepting short-term ups and downs). Interest outside an ISA may be taxed above your Personal Savings Allowance — ISAs sidestep that entirely.
How does a starting pot change the monthly amount?
It works twice: the pot reduces the gap to close, and it compounds untouched for the entire period. Even with no interest at all, £5,000 toward a £20,000 goal over 5 years cuts the monthly figure from £333 to £250 — and at a positive rate the saving is larger still, because the pot's growth does part of the job for you.
What is a quick way to estimate the monthly amount without the calculator?
Divide the remaining gap by the number of months: (£goal − £current pot) ÷ months. That is the zero-interest answer and always slightly overstates what you need, so it is a safe upper bound. £20,000 from zero over 60 months is £333; the true figure at 4.5% is about £280, and the gap between the two is exactly what interest contributes.
What interest rate should I enter?
The rate your money will actually earn: your account's quoted rate for cash savings, and an after-tax rate if the interest will be taxed outside an ISA. The tool assumes the rate holds for the whole period, so for long horizons treat the output as a good estimate rather than a promise — rates move, and it is worth re-running the numbers when yours changes.
Is it better to extend my deadline or find a higher rate?
For most goals, the deadline is the stronger lever. Reaching £10,000 from zero at 4% needs about £394 a month over 2 years but only £151 over 5 — a far bigger drop than any realistic rate improvement could deliver. Rates matter increasingly as the horizon stretches, which is why the two levers work best together on long-term goals.