# Investment calculator for Mac, Windows and Linux

Written on 25 October 2026 by Ratio.

Type the question the way you'd ask it, “save 500/month at 7% for 20 years”, and change any number to see what moves.

## Saving and growing

| save 500/month at 7% for 20 years | 260,463.3299 |
| --- | --- |
| 10k at 4% for 5 years | 12,166.529 |
| cagr(1000, 2500, 5 years) | 20.1124% |
| roi(1000, 1500) | 50% |
| 5% minus 3% inflation | 1.9417% |

Hover the savings line for what you paid in and what the growth added.

## Financial independence

The FIRE number is a year's spending divided by a safe withdrawal rate, 4% unless you give one.

| fire 40k/year | 1,000,000 |
| --- | --- |
| fire 3000/month at 4% | 900,000 |

## Loans, break-even and depreciation

| amortize 200k at 5% for 30 years | 1,073.6432 |
| --- | --- |
| break even fixed 5000, price 50, cost 30 | 250 |
| depreciate 10000 over 5 years | 2,000 |
| ddb(10000, 1000, 5, 1) | 4,000 |
| syd(10000, 1000, 5, 1) | 3,000 |

`amortize` lists each year's interest, principal and remaining balance when you hover it. More in the [loan calculator](https://useratio.app/loan-calculator).

[Try Ratio free for 7 days](https://useratio.app/download) · $14.99 once, updates included

## Questions

**Does it compound monthly?** Savings written per month compound each month. For a lump sum, add “compounded monthly”: “5000 at 7% for 3 years compounded monthly”.

**What is the real return?** What a return is worth after inflation: (1 + 5%) ÷ (1 + 3%) − 1 = 1.94%, not 2%.

**Is this financial advice?** No. Ratio does the arithmetic; returns are never guaranteed.

Source: https://useratio.app/investment-calculator