Rent vs Buy Calculator
Work out how long you need a tool or machine before buying beats renting, counting what you get back when you sell it.
"Per day" is whatever period the rental is quoted in — days, weeks, months — as long as every figure uses the same one. Resale is a flat amount recovered at the end. Nothing is uploaded.
What buying costs is the price minus what comes back
A tool renting at $75 a day against $900 to buy, $15 a day to run and $350 back when you sell it. Compare the rent against the purchase price and buying takes 15.0 days to pay off. Compare it against what buying actually costs — $550, because $350 comes back — and it takes 9.2. The same decision on the same numbers, moved by 64%.
| If you sell it for | Buying really costs | Break-even |
|---|---|---|
| $0 | $900 | 15.0 days |
| $100 | $800 | 13.3 days |
| $200 | $700 | 11.7 days |
| $350 | $550 | 9.2 days |
| $500 | $400 | 6.7 days |
| $700 | $200 | 3.3 days |
Every dollar you expect to recover is worth exactly the same amount of break-even — one dollar over the daily saving — so the relationship is a straight line with no diminishing returns anywhere in it. The mistake being corrected is treating the purchase price as the cost. It is the amount you hand over; the cost is the part that does not come back. For anything with a second-hand market that difference is large, and it gets ignored because the price is printed on the shelf while the resale value is a guess you have to make yourself.
Sometimes buying never wins
Renting is not only a way of spreading the price. The rate usually bundles the servicing, insurance, storage and delivery that an owner pays separately, and when those come to more than the rental itself, no length of ownership recovers the difference. At $80 a day to run against $75 to rent, the gap between owning and renting only widens with time — the break-even is not a large number but no number at all, and this calculator says so instead of quoting something far in the future that reads like the same answer. It is worth checking honestly, because running costs are the ones an owner tends to forget and a rental company has already priced in.
How to use
- Enter the rental rate and the purchase price.
- Add what it costs you to run, and what you could sell it for.
- Say how long you need it.
- Read the break-even and the cheaper option for your span.
Frequently asked questions
How long before buying beats renting?
What buying costs, divided by what you save each period. The trap is the first number: a $900 tool you could sell for $350 costs you $550, not $900. Against a $75 daily rental and $15 a day to run, that is 9.2 days rather than 15 — the same decision on the same numbers, moved by 64%.
Why is the purchase price not the cost?
Because it is the amount you hand over, not the amount you lose. The cost is the part that does not come back. For anything with a second-hand market that difference is large, and it gets left out because the price is printed on the shelf while the resale value is a guess you have to make yourself.
Does buying always win eventually?
No, and this is the case people miss. A rental rate usually bundles the servicing, insurance, storage and delivery that an owner pays separately. When those come to more than the rental itself, the gap only widens with time and there is no break-even at any length — not a large number, no number.
How much is resale value worth?
Every dollar you expect to recover shortens the break-even by the same amount, one dollar over the saving per period, so the relationship is a straight line with no diminishing returns. Doubling a realistic resale estimate can move a break-even by a third or more.
What period should I use?
Whichever the rental is quoted in — days, weeks or months — as long as every figure uses the same one. Mixing a daily rental with a monthly running cost produces a number with no meaning.
What about storage and transport?
Put them in the running cost, since they are what ownership costs you each period. They are the ones most often forgotten, and they are exactly what a rental company has already priced into its rate, which is part of why renting looks worse than it is on a naive comparison.
Does this work for anything other than tools?
Any decision shaped the same way: pay per use, or buy and run it yourself. Equipment, vehicles, instruments, event gear. It is not a model for renting versus buying a home, which turns on mortgage interest, tax and property appreciation and needs a different calculation.
Does this send anything anywhere?
No. Every figure is computed in your browser, and nothing is uploaded or stored.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.