FinToolSuite

Savings Projection by Rate Calculator

Updated April 17, 2026 · Savings · Educational use only ·

Compare savings projections at different rates.

Compare how savings grow at low, medium, and high expected rates. Free calculator with the working shown and a worked example.

What this tool does

Enter monthly savings and horizon. The tool projects values at 3%, 5%, and 7% returns.


Enter Values

Formula Used
Monthly savings
Monthly rate
Months

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Calculations, display, or translation — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

400/month for 20 years: at 3% grows to 131,000; at 5% 165,000; at 7% 208,000. 4 percentage point gap = 77,000 over 20 years. Return assumptions are more impactful than most people realise over long horizons. Choose conservatively when planning; revise up if reality exceeds.

Run it with sensible defaults

Using monthly savings of 400, horizon of 20, the calculation works out to 208,370.66. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Monthly Savings and Horizon — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

Future value of monthly annuity at 3%, 5%, 7%. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

How to use this beyond the first run

Re-run the calculation once a year. Life changes — pay rises, new expenses, interest-rate shifts — and the figure that looked right 12 months ago often isn't today. Annual recalibration keeps the plan honest.

What this doesn't capture

The calculation assumes a steady savings rate and a stable interest rate. Real saving journeys include emergencies, windfalls, and rate changes — especially in easy-access products. The figure is a direction of travel, not a guarantee.

Related calculations worth running

Plans get firmer when you triangulate. Alongside this one, the compound interest calculator, the wealth building rate calculator, and the drawdown calculator global tend to come up in the same conversations. Running two or three together exposes inconsistencies in any single assumption — which is usually where the useful insight lives.

Example Scenario

Savings projection produces three scenarios based on the inputs provided.

Inputs

Monthly Savings:400 £
Horizon:20
Expected Result£208,370.66

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Future value of monthly annuity at 3%, 5%, 7%.

Frequently Asked Questions

Which rate to plan with?
Conservative planning uses 4-5%. Aggressive equity portfolios 7-8%. Cash 2-3%. Choose based on your actual asset mix.
Why sensitivity matters?
Small rate differences compound dramatically. 3% vs 7% over 30 years = 2.4× difference in final value.
What if reality differs?
Revisit projection annually. Adjust contributions if returns disappoint; bank excess if they exceed.
Real vs nominal?
These are nominal values. Real purchasing power = nominal / (1 + inflation)^n. Use real rates for purchasing power planning.

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