Money
What If I Saved £100 Every Month?
What if I saved £100 every month?
Monthly is how most UK bills arrive, so it is a natural unit for a surplus. One hundred pounds a month is £1,200 a year and £12,000 in a decade if nothing is added in interest — a clean enough number to hold in your head. This experiment lets the monthly amount run from £25 to £1,000, defaults to ten years, and starts the illustrated rate at 4%. That 4% is a teaching figure, not a recommendation and not a product. Set it to zero to see contributions only. MoneyHelper’s budget planner is the grown-up tool for asking whether £100 is even free to leave the current account.
Change this
Results update as you move the controls.
Optional. Not guaranteed.
Your result
£14,725
illustrated total
£12,000 put in · £2,725 illustrated growth
- Contributions
- £12,000
- Illustrated growth
- £2,725
- Per year put in
- £1,200
- Rate used
- 4%
Optional, not guaranteed
What does that mean?
£100 a month for 10 years, illustrated at 4% a year, is about £14,725. Of that, £12,000 is money you put in and £2,725 is illustrated growth. Interest is not guaranteed; fees, tax and inflation are outside the model.
Timeline
1 year
£1,222
£1,200 put in, £22 illustrated growth.
5 years
£6,630
£6,000 put in, £630 illustrated growth.
10 years
£14,725
£12,000 put in, £2,725 illustrated growth.
Compare
| 0% (contributions only) | £12,000 | No growth assumed |
|---|---|---|
| 3% illustration | £13,974 | Not a forecast |
| 5% illustration | £15,528 | Not a forecast |
Compare scenarios
A standing order is a decision you only make once
Daily experiments assume a heroic streak of cash discipline. A monthly amount can be a standing order, which is why this page exists. The engine treats each contribution as arriving at the end of the month. Missed months are not modelled; if the habit would actually skip August, this total is too high.
Four percent is a chalkboard, not an offer
The default rate sits a little above the Bank of England’s 2% inflation target so you can see compounding do something. It may be higher or lower than any real account you can open this week, and it will not stay still. Fees and tax are omitted. If the growth line is doing more work than the contribution line in your head, turn the rate back to zero.
Raising the amount later
People rarely save the same pounds for ten years. The escalating-savings experiment next door increases the monthly figure each year. Starting ten years earlier asks a different question with the same monthly engine. Use this page when the amount is flat, or when you want the simplest picture.
How we calculated this
Future value of an ordinary annuity: monthly contributions for years × 12 periods, compounded at annualRate ÷ 12. At a zero rate the total equals monthlyAmount × years × 12. This experiment provides estimates for educational purposes and is not financial advice. Actual results vary depending on rates, fees, taxes, inflation and individual circumstances. Interest is optional and not guaranteed.
Go further
A curated rabbit hole from this question. Each link is a real experiment, not a random suggestion.
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