# A loan calculator you can read back

Every example was run through Ratio 0.6.1 on 15 October 2026. Results are shown with 2 decimals (Settings › Decimals).

Describe the loan the way you'd say it, and Ratio gives you the monthly payment. Add a line for the total, another for the interest. Then change one number and watch the whole sheet follow.

## Monthly payment

| loan 200k at 5% for 30 years | 1,073.64 |
| --- | --- |
| loan 25k at 7.5% for 5 years | 500.95 |

## What a mortgage really costs

| payment = loan 200k at 5% for 30 years | 1,073.64 |
| --- | --- |
| payment * 360 | 386,511.57 |
| prev - 200k | 186,511.57 |

## Watch your savings grow

| 10k at 4% for 5 years | 12,166.53 |
| --- | --- |
| 5000 at 7% for 3 years compounded monthly | 6,164.63 |

## The spreadsheet functions you know

The same arguments as Excel or Numbers: rate per period, number of periods, amount.

| pmt(6%/12, 60, 25000) | 483.32 |
| --- | --- |
| npv(10%, 100, 200, 300) | 481.59 |
| irr(-1000, 300, 400, 500) | 8.9% |

More in the [syntax reference](https://useratio.app/docs#loans).

Ratio runs on [Mac](https://useratio.app/), [Windows](https://useratio.app/notepad-calculator-windows) and [Linux](https://useratio.app/notepad-calculator-linux) with the same engine, so every example here gives the same answer on all three.

[Try Ratio free for 7 days](https://useratio.app/download) · $9.99 once, updates included

## Questions

**How do I calculate a monthly loan payment on a Mac or PC?** In Ratio, type “loan 200k at 5% for 30 years”. The monthly payment (1,073.64) appears beside it. “pmt(5%/12, 360, 200000)” gives the same.

**How much interest will I pay in total?** Name the payment, multiply by the number of months and subtract the loan: “payment * 360” then “prev - 200k” (186,511.57 for the example above).

**Is this financial advice?** No. Ratio does the arithmetic; check the terms of a real loan with your lender.

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