$100 a week invested for 20 years

Use conservative, mid, and optimistic return assumptions to see a realistic range of outcomes — then decide what’s feasible for your budget.

Open the Money Growth Calculator

Quick answer

If you invest $100/week for 20 years, the result depends heavily on the return rate. Use the calculator to test a conservative, mid, and optimistic scenario.

How to enter it in the calculator

Weekly amount: $100/week
Convert to monthly: about $433/month ($100 × 52 ÷ 12)
Timeline: 20 years
Test return rates: 5%, 7%, and 10%

Make the plan stronger

Increase contributions as income grows (even +$10/week helps over time).
Stay consistent through market ups and downs.
Keep fees low where possible — fees compound too.

Disclosure: This page contains affiliate links. If you sign up through these links, I may earn a commission at no extra cost to you.

Want to actually stick to this plan?
Tools like Pocketsmith can help you manage your money and stay on track.

👉 Plan your finances with Pocketsmith

FAQ

Is $100/week a good amount?

It’s a solid starting habit. The best amount is one you can maintain consistently, then increase over time.

What return rate should I assume?

Use 5% for a conservative baseline, 7% for a mid-range estimate, and 10% as an optimistic scenario.

Does this account for inflation, tax, or fees?

No. Treat results as estimates. You can lower your assumed return rate to be more conservative.

Weekly vs monthly contributions — does it matter?

For long-term modelling, converting to monthly is usually close enough.

Where can I learn how the maths works?

See the simple explanation on /how-compound-interest-works.html.

$100 a week invested for 20 years

Quick answer

How to enter it in the calculator

Make the plan stronger

FAQ

Related links

Try another calculator