How to use this calculator
- Enter or choose starting amount.
- Enter or choose contribution.
- Enter or choose contribute.
- Enter or choose contributions made at the.
- Enter or choose increase contributions each year by.
- The end balance updates as you type. Use Copy result or Share to keep it.
Method
Per-period return i = (1 + R)^(1/f) − 1; each period: Balance = Balance × (1 + i) + C (or (Balance + C) × (1 + i) at the start); C rises by the yearly increase each year
- R
- expected annual return (effective)
- f
- contributions per year (12 or 1)
- C
- contribution per period
Worked example
- A 7% yearly return is 1.07^(1/12) − 1 = 0.5654% a month.
- The 10,000 grows to 10,000 × 1.07^10 = $19,671.51.
- 120 deposits of 200 grow to 200 × (1.005654^120 − 1) ÷ 0.005654 = $34,210.35; total $53,881.86 from $34,000 invested.
- In today’s money: 53,881.86 ÷ 1.025^10 = $42,092.42.
Investing $10,000 plus $200 a month at 7% a year gives about $53,881.86 after 10 years, $19,881.86 of it growth.
What the result means
Growth overtakes contributions only after many years; the line chart shows when. Raising contributions each year in line with pay rises is often the easiest way to boost the end result.
Assumptions and limits
- The return is the same every year and is an effective annual rate.
- Fees and taxes are not deducted; use a return net of fees.
- Real investments go up and down; a constant-rate projection shows a smooth path that markets do not follow.
Questions
Should I pick start or end of period?
If you invest on payday at the start of each month, choose start. It adds one period of growth to each contribution.
How do I solve for the return or contribution I need?
Use the Finance Calculator: leave the unknown value blank and it solves for it.
Please note: Returns are illustrations at a constant rate, not predictions or guarantees. Investments can lose value. This is not investment advice.