UK Savings Goal Calculator — ISA & Compound Interest

The standard rule is to save 20% of your take-home pay — the 50/30/20 budget splits income into needs (50%), wants (30%), and savings (20%). For a £2,500 monthly net salary, that is £500/month to save money consistently. The right figure depends on your goal: enter a target, timeline, and interest rate into this calculator to get the exact monthly amount needed. Even small amounts to save money early make a difference — consistent regular contributions over 5–10 years outperform irregular lump sums thanks to the long term power of compound interest.

The ISA allowance for 2025/26 is £20,000 per person. Cash savings held in a Cash ISA earn savings interest tax-free — no income tax on interest earned, regardless of your tax band. At current easy-access rates of around 4–5%, that could mean £800–£1,000 in tax-free savings interest in a single year. If you are considering whether to start investing instead of keeping cash savings, a Stocks and Shares ISA within the same £20,000 allowance offers potentially higher long term growth — though with greater risk. Use the isa calculator feature to model both cash savings scenarios.

Compound interest earns you interest on your interest, not just the original amount of money deposited. For example, £10,000 saved at 4.5% per year for 10 years grows to £15,530 — £5,530 in savings interest earned without adding another penny. The earlier you start, the bigger the effect. Making regular contributions accelerates growth further: adding £200/month to that same £10,000 at 4.5% over 10 years builds a pot of over £45,000. This compound interest calculator uk shows the year-by-year balance so you can see exactly how your savings grow.

A common saving by age benchmark: aim to have 1× your annual salary saved by age 30, 3× by age 40, and 6× by age 50. For someone earning £35,000, that means approximately £35,000 by 30 and £105,000 by 40. These figures include pension savings — workplace pension contributions count. For non-pension cash savings, aim for 3–6 months of essential expenses as an emergency fund first. The best time to save money is always as early as possible — time in a savings account compounds significantly. Use this calculator to set a realistic monthly saving rate from where you are now.

For a £250,000 property, a 5% deposit is £12,500 and a 10% deposit is £25,000. As a rough guide, saving £600/month at 4.5% savings interest gets you to £25,000 in under 3.5 years. Enter your target deposit amount of money, current savings balance, and how much you can put aside monthly — the calculator shows your target date and whether your regular contributions will get you there on time. First-time buyers should also factor in Stamp Duty, legal fees, and survey costs on top of the deposit.