Saving & Investing Calculators
See how money grows over time. See what it takes to hit a goal. Every calculator shows the formula and the steps with your numbers. 401(k) figures use the 2026 IRS limits, so the employee deferral is $24,500.
Why time matters more than timing
Say you invest $300 a month for 30 years at a 7% average annual return. You end with about $350,836. You only put in $108,000. The other $242,836 is growth on top of growth. Stop on that number for a second. Now start the same plan 10 years later. You end with about $152,261. Same $300 a month. Ten fewer years. In other words, the first decade does a lot of the work.
How much does a lump sum grow?
Pick an amount and a time frame. The linked pages show growth at 4%, 6%, 8% and 10%, with and without monthly additions.
| Amount | 5 yrs | 10 yrs | 15 yrs | 20 yrs | 25 yrs | 30 yrs | 40 yrs |
|---|---|---|---|---|---|---|---|
| $1,000 | $1,469 | $2,159 | $3,172 | $4,661 | $6,848 | $10,063 | $21,725 |
| $5,000 | $7,347 | $10,795 | $15,861 | $23,305 | $34,242 | $50,313 | $108,623 |
| $10,000 | $14,693 | $21,589 | $31,722 | $46,610 | $68,485 | $100,627 | $217,245 |
| $25,000 | $36,733 | $53,973 | $79,304 | $116,524 | $171,212 | $251,566 | $543,113 |
| $50,000 | $73,466 | $107,946 | $158,608 | $233,048 | $342,424 | $503,133 | $1,086,226 |
| $100,000 | $146,933 | $215,892 | $317,217 | $466,096 | $684,848 | $1,006,266 | $2,172,452 |
The table uses an 8% average annual return. No withdrawals. No taxes.
Frequently asked questions
What is a realistic rate of return to use?
The S&P 500 returned about 10% a year from 1928 to 2025 with dividends, before inflation (NYU Stern / Damodaran data). Many planners use 6-7% for a stock-heavy portfolio. That leaves room for fees, inflation and bad decades. Savings accounts and CDs pay far less.
What are the 2026 401(k) limits?
Employees can defer up to $24,500 in 2026. Workers 50 and older can add $8,000. Workers aged 60 to 63 can add $11,250 instead. The source is IRS Notice 2025-67.
Do these calculators include taxes?
No. Results are pre-tax. Money in a 401(k) or traditional IRA is taxed when you withdraw it. Roth accounts can be tax-free. A taxable brokerage account owes tax on dividends and realized gains.
Not investment advice. These results are estimates. They use the numbers you enter and a constant rate of return. Real returns change every year. They can be negative. They are not guaranteed. Taxes, fees and inflation will change your real results. Talk with a licensed financial professional before you decide.
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Updated: October 2, 2026 · Sources and methodology