If $1,000 grew at a steady 7% per year, compounded annually, with nothing added or taken
out, it would reach $1,967.15 after 10 years, $3,869.68 after
20 and $7,612.26 after 30. Here is the full picture — and a calculator preset
with this scenario so you can change the assumptions.
Why the last decade does most of the work
Look at the interest column: in the first 10 years $1,000 earns
$967.15 of interest. In the third decade alone it earns roughly
$3,742.57 of growth — more than the balance at the
10-year mark — because by then the interest is being calculated on two decades of
accumulated gains, not on the original $1,000. Nothing about the rate changes; the base
it applies to keeps growing. That back-loaded shape is the defining feature of compound
growth, and it is why these tables always look unimpressive early and dramatic late.
The flip side matters just as much: because so much of the total comes from the final
years, interrupting the process — or earning a lower rate than assumed — cuts the outcome
disproportionately. Use the calculator below to test this scenario at 4% or 5% and compare.
Frequently asked questions
Is 7% a promised or typical return?
Neither. It is a round, commonly used classroom assumption chosen so the arithmetic is easy to follow. No product on this site is being described, and no return is promised anywhere.
What would $1,000 be worth at a different rate?
Change the rate in the calculator above. As a rough guide, each percentage point of rate matters more the longer the horizon — at 30 years the difference between 6% and 7% is far larger than the same gap at 10 years.
Does this include taxes, fees or inflation?
No. Figures are gross and nominal. Inflation in particular would make the future amounts buy less than the same numbers buy today.