5% Compound Interest Calculator
Use this page when you want to model a steady 5% annual return. It works well for conservative long-term assumptions, bond-heavy portfolios, and cautious savings projections.
Year-by-year breakdown
| Year | Ending balance | Total contributed | Total interest |
|---|
When a 5% assumption is useful
A 5% annual return is often used as a conservative planning number. It can help you stress-test a goal without relying on aggressive assumptions that make the final balance look better than reality.
How to read the result
- Treat the final value as an estimate, not a promise.
- Use the year-by-year table to see whether your contribution level is doing enough work.
- Compare this page with a 7% version to see how sensitive your plan is to return assumptions.
Good next comparisons
What 5% looks like over different horizons
5% is roughly what a good cash savings account or a conservative bond-heavy portfolio might target. It is the rate to use when the money must be there on a date and cannot be exposed to a bad decade. Every row uses this page's inputs — $10,000 to start and $250 a month — with 5% compounded monthly and contributions at the end of each month.
| After | You contributed | Balance | Interest earned |
|---|---|---|---|
| 5 years | $25,000 | $29,835 | $4,835 |
| 10 years | $40,000 | $55,291 | $15,291 |
| 15 years | $55,000 | $87,959 | $32,959 |
| 20 years | $70,000 | $129,885 | $59,885 |
| 25 years | $85,000 | $183,690 | $98,690 |
| 30 years | $100,000 | $252,742 | $152,742 |
Over the 20-year horizon this page defaults to, $70,000 of contributions becomes about $129,885. Extending to thirty years reaches $252,742 — the extra years are worth far more than the extra deposits that fund them.
How much the 5% assumption is actually carrying
The honest way to use a rate-specific calculator is to check what happens if the rate is wrong. Over 20 years, on the same contributions:
| Annual return | Final balance | vs 5% |
|---|---|---|
| 3% | $100,283 | -23% |
| 4% | $113,919 | -12% |
| 5% (5% — this page) | $129,885 | — |
| 6% | $148,612 | +14% |
| 7% | $170,619 | +31% |
Two points either side of 5% moves the 20-year result from about $100,283 to $170,619 — a spread of $70,336 on identical contributions. That spread is the uncertainty in the plan, and no calculator can narrow it. What you can do is decide which end of it your plan needs to survive.
- Fees come straight off the rate. A 1% annual charge on 5% behaves like 4%, costing about $15,965 over 20 years here.
- Inflation is not deducted. At 2.5%, $129,885 in 20 years buys about what $79,265 buys today.
- A constant rate is a modelling device. Real returns arrive out of order, and the order matters once you start withdrawing.
Questions about 5% returns
How much does $10,000 grow at 5%?
On its own, with no contributions, $10,000 at 5% compounded monthly reaches about $27,126 in 20 years. Adding $250 a month takes it to roughly $129,885.
How long does money take to double at 5%?
About 13.9 years with monthly compounding. The Rule of 72 estimates 72 ÷ 5 = 14.4 years, which is close enough to do in your head.
Is 5% a realistic assumption?
5% is roughly what a good cash savings account or a conservative bond-heavy portfolio might target. It is the rate to use when the money must be there on a date and cannot be exposed to a bad decade. Whatever rate you choose, run the plan at one or two points lower as well — if it only works at the optimistic figure, it is not yet a plan.