Retirement Compound Interest Calculator
This page answers a practical question: how much could you have by retirement if you start with a given balance, add money every month, and earn a long-term average return. It uses monthly compounding and monthly contributions for a planning-level estimate.
What matters most for retirement growth
- Time usually matters more than trying to guess a perfect return number.
- Monthly contribution consistency matters more than occasional large deposits.
- Starting earlier lowers the pressure on future monthly savings.
Use this page correctly
This is a planning calculator, not a promise. Real portfolios move up and down. Use conservative assumptions, then compare more than one return scenario on the main compound interest calculator.
Related retirement-style pages
What a retirement projection is really made of
A retirement projection is the same compound interest calculation as everything else on this site, with one difference that changes how you should read it: the horizon is fixed by your age, not chosen. The table below assumes $50,000 already invested, $600 a month, and 7% compounded monthly.
| Current age | Years to 65 | Total contributed | Balance at 65 | Income at 4% |
|---|---|---|---|---|
| 30 | 35 | $302,000 | $1,655,940 | $66,238 |
| 35 | 30 | $266,000 | $1,137,807 | $45,512 |
| 40 | 25 | $230,000 | $772,314 | $30,893 |
| 45 | 20 | $194,000 | $514,493 | $20,580 |
| 50 | 15 | $158,000 | $332,625 | $13,305 |
| 55 | 10 | $122,000 | $204,334 | $8,173 |
The final column is the one that matters. A balance is not a retirement; the income it can sustain is. Converting the projection into an annual figure makes it comparable with your actual spending, which is the only question the plan is really trying to answer.
Every other calculation on this site is about accumulation, where a bad year averages out against later contributions. Retirement adds a withdrawal phase, where the order of returns matters enormously — a severe fall in the first few years of drawing down does damage that a later recovery cannot fully undo. That is why a projection should be treated as one scenario among many, not as a number to plan precisely against.
The adjustments most projections leave out
- Inflation. A balance of $1,137,807 in thirty years has roughly the purchasing power of $542,441 today.
- Employer contributions. Include them — matching is a return on your deposit before any market growth.
- Rising contributions. Most careers allow deposits to increase. A flat figure understates a realistic plan.
- State or workplace pensions. They reduce how much the portfolio has to cover, sometimes dramatically.
- Tax on withdrawal. The 4% column above is gross. What you can spend depends on the account type.
The inflation-adjusted version and the withdrawal rate calculator handle the two largest of these adjustments directly.
Questions about retirement projections
How much will I have at retirement?
With $50,000 invested, $600 a month and 7% compounded monthly, someone aged 35 reaches about $1,137,807 by 65. At 45 the same plan reaches roughly $514,493.
What return should I assume for retirement planning?
One you would still accept in a poor decade. Many people model 5% and 7% and build the plan on the lower figure, treating the difference as margin.
Should I include my pension in the projection?
Include everything invested for retirement, including employer contributions. State pensions are better handled separately, as income that reduces what the portfolio must supply.
Is it too late to start at 50?
Later, not too late. Fifteen years of $600 a month from $50,000 still reaches about $332,625 at 7%. The difference is that contributions do most of the work, so the size of the deposit matters far more than it would at 30.