FinToolSuite

Subscription to Investment Calculator

Updated April 17, 2026 · Psychology & Behavioral · Educational use only ·

Future value of redirecting a monthly subscription into investments instead.

See what cancelling a subscription and investing the monthly amount could grow to over years. Enter return and see the result instantly.

What this tool does

Every unused subscription has a second life as invested capital. Enter the monthly subscription amount, expected annual return, and years. The tool returns the compound future value of redirecting that money into an investment account instead.


Enter Values

Formula Used
Monthly subscription
Monthly return rate
Total 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.

15 a month cancelled and invested at 7% for 30 years grows to roughly 18,300. That single 15 decision compounded across a career is meaningful money. Most households have two or three unused subscriptions — the combined FV tends to be surprising once calculated.

How to use it

Enter the monthly subscription cost, an expected annual return, and your horizon. The tool projects the future value assuming the monthly amount is invested each month instead.

Use it for auditing

Run the tool for each questionable subscription. Anything over 10/month that you don't actively use compounds into a surprising figure. The decision isn't about the 10 — it's about the FV that 10 quietly represents.

A worked example

Try the defaults: monthly subscription of 15, annual return of 7%, years of 30 years. The tool returns 18,299.56. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Monthly Subscription, Annual Return, and Years. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

The formula behind this

Ordinary annuity future value with monthly compounding. Assumes the monthly amount is invested at the end of each month — standard approximation for regular investing. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Why the behavioural angle matters

Most personal finance mistakes are behavioural, not mathematical. You know the math; the hard part is acting on it consistently. Calculators like this one are useful because they externalise a private feeling into a public number — and public numbers are easier to argue with than vague feelings.

What this doesn't capture

Behaviour-adjacent math is always an approximation. Human habits are lumpy and context-dependent; the figure here assumes steady behaviour which is a simplification. Treat the output as a prompt for thinking rather than a precise prediction.

Example Scenario

The future value of the redirected subscription is shown above.

Inputs

Monthly Subscription:15 £
Annual Return:7
Years:30
Expected Result£18,299.56

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

Ordinary annuity future value with monthly compounding. Assumes the monthly amount is invested at the end of each month — standard approximation for regular investing.

Frequently Asked Questions

Is this realistic?
Math is exact. Whether you actually redirect and invest depends on you — the money needs to go into an investment account, not absorbed by other spending.
What return rate?
Long-term equity averages 5-8% nominal. 7% is a middle-of-the-road assumption. Lower return if invested in cash savings (2-5%).
Multiple subscriptions?
Add them up and run once. 15 + 12 + 8 = 35/month redirected at 7% for 30 years is roughly 42,700 FV.
Does this account for subscription price rises?
No — assumes flat. Real subscriptions typically rise 5-10% a year, so the real FV of redirecting is slightly higher than the tool shows.

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