How much should I save for retirement?

Aim for 15–20% of your gross income, including employer contributions. The earlier you start, the lower this percentage needs to be. Use the calculator to find the monthly amount that reaches your target.

The 4% rule suggests you can safely withdraw 4% of your retirement pot each year without running out of money over a 30-year retirement. So a £500,000 pot would provide £20,000/year.

Should I use a pension or ISA for retirement?

Pensions offer tax relief on contributions (20–45%) and employer matching, but you can't access them until age 55 (rising to 57). ISAs are more flexible. Most people benefit from using both.

Should I account for inflation?

Yes. Inflation erodes purchasing power over time. Use the Advanced Settings to add an inflation rate (2–3% is typical for the UK) to see your results in today's money. This gives a more realistic picture of future wealth.

What's the best strategy for compound growth?

Start early, contribute consistently, and let time do the work. Even small amounts grow significantly over decades. Increasing your contributions by a small percentage each year (use Advanced Settings) can dramatically boost your final balance.

CompoundWise

Turn £300/month into £597,847

Free UK calculator · No signup · Based on ISA investing

By CompoundWise Team·Updated April 2026

Starting amount

£0£20k£200k

Monthly contribution

£0£1k£5k

Expected annual return

Time horizon

yrs

Invest £300/month for 35 years at 7%

£466,847

earned in interest alone

That's more than you put in, your money earns money

Total value

£597,847

You put in

£131,000

Your money78% from compounding

To reach £597,847, most UK investors use a Stocks & Shares ISA

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Keeping this in a savings account? You'd have ~£303,682 less

Compared to investing at 7% vs a 4% cash savings account

Growth Over Time

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Quick Scenarios

Your Personalised Insights

Year 17: your interest overtakes your contributions. From here, compounding does the heavy lifting.
Your money earns ~£37/day in interest. That's £466,847 earned while you sleep.
Saving just £50 more per month would add £90,053 to your final balance. That's £21,000 invested for £90,053 extra.
5 more years would add £271,154, nearly 45% more, showing how powerful time is.
Starting 5 years earlier would add £191,273 to your final balance. Every year you wait costs real money.Start investing now →
Consistency beats timing, investing £300/month for 35 years matters more than picking the perfect moment to start.
At your current plan, you reach £500k in 33 years. That's a real milestone, and it compounds from there.Start building towards it →

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By the CompoundWise Team · Updated April 2026

UK-based financial education · Not financial advice

How much do you need to retire?

A common rule of thumb is to aim for a retirement pot of 25 times your desired annual income, known as the "4% rule." If you want £30,000/year in retirement, you'd need approximately £750,000. That sounds daunting, but compound interest makes it achievable: £300/month at 7% over 35 years grows to roughly £553,000, with only £126,000 contributed from your pocket.

The cost of waiting to start

Every year you delay starting a retirement fund costs you disproportionately. Starting at 25 with £200/month at 7% gives you about £525,000 by 65. Starting at 35 gives you only £244,000, less than half, despite saving for 30 years instead of 40. The first years of investing are the most valuable because they compound the longest.

Workplace pensions and compound interest

If your employer offers pension matching, that's an immediate 100% return on your contribution. Combined with compound interest, employer matching dramatically accelerates growth. Many UK workers are auto-enrolled at 5% employee + 3% employer contributions. Use this calculator to see how topping up your pension beyond the minimum could transform your retirement outcome.

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