Contribution calculator
See what investing more each month could change
Compare monthly contributions side by side: what each could grow to, how much is your own money, and how much sooner you could reach a target.
Free calculator · No sign-up required
Illustrative example from the demo household. Estimates assume a steady return and are not predictions or advice.
Try the contribution calculator
Start from the example or enter your own figures. Results update as you type.
Estimated value after 10 years
£1,176,208
About £918,852 in today’s money at 2.5% inflation
- Total paid in
- £727,400
- Estimated growth
- £448,808
- At £3,300/mo
- +£82,488
- £1,258,696 in total
- Reaching £1,050,000
- In 8 years 9 months
- 7 months sooner at £3,300
Chart: After 10 years: estimated value £1,176,208, of which £727,400 paid in and £448,808 investment growth. At £3,300 a month: £1,258,696. Target £1,050,000: in 8 years 9 months.
How it calculates
Simple arithmetic, stated plainly
- Monthly compounding
- Each contribution is added at the start of the month; growth uses the monthly equivalent of your annual return, (1 + r)^(1/12) − 1. This is the same convention as the Yield Clarity forecast.
- Future money
- Results are nominal. The today's-money figure divides by compounded inflation.
- A steady return
- Real returns vary from year to year and can be negative. Nothing here is guaranteed or advice.
In Yield Clarity
Real plans rarely have one contribution
The app applies contributions to your recorded FI-eligible wealth and shows what each change does to your estimated FI date.
- Available on Plus and Pro
Contributions that change over time
Dated phases: more now, less later, or a career break at £0.
- Included on Free
Contributions that stop at FI
Stop automatically when you reach your target or retire.
- Included on Free
Your estimated FI date
From your real FI-eligible wealth and FI target, not one typed number.
- Available on Plus and Pro
Probability and scenarios
See how a contribution changes your probability of reaching FI, and compare saved scenarios.
Questions
Contribution calculator, answered
Is the expected return guaranteed?
No. The calculator assumes the same return every year to show the effect of compounding. Real returns vary, can be negative, and the order they arrive in matters. Treat the result as an illustration, not a forecast.
Does this include fees, tax or account and pension allowances?
No. Use a return net of the fees you expect. Tax, tax relief and allowances aren't modelled.
Why does a target date use months rather than a calendar date?
The time to a target depends only on the inputs, so it's shown as a duration. In Yield Clarity the same calculation gives a dated estimate from your recorded position.
What's different in the Yield Clarity app?
The app starts from the assets you've recorded, supports contribution phases and stopping at FI, and shows the effect on your estimated FI date. Contribution phases, Monte Carlo and scenarios are included in Plus and Pro.
Compare plansPut your contributions into a real plan
Add your assets and your FI target to see how your contributions change your estimated FI date.
No card required for the Free plan.