How rental charges are calculated
- Count the days each batch was out — from the day the items went out to the day that batch came back. With the return day counted, 1 March to 15 March is 15 days. A same-day hire still bills one day.
- Convert days into billing periods. A daily rate is one period per day. For weekly rates every started week of 7 days counts in full, and for monthly rates every started 30 days does.
- Multiply: items in the batch × rate × periods.
- Add the batches, then tax, then take off the deposit to get the balance due.
Worked example: 200 chairs, three batches
200 chairs go out on 01 Mar 2026 at £3.50 per chair per day. 80 come back on 15 Mar 2026 (15 days), 60 on 22 Mar 2026 (22 days), and the last 60 are billed up to 29 Mar 2026 (29 days). The charges are £4,200.00, £4,620.00 and £6,090.00 — a hire charge of £14,910.00, or £17,892.00 with 20% tax.
Why bill each batch separately?
Charging all 200 chairs for the full 29 days would overcharge the customer for the 140 that came back early. Charging all 200 up to the first return date would undercharge you for the 60 that stayed out. Billing each batch for the days it was actually out is the only fair answer — and the part that is hardest to keep right on paper or in a spreadsheet once several orders are running at once.
Frequently asked questions
Should the return day count as a rental day?
Most hire businesses charge for both the day items go out and the day they come back, so 1 March to 15 March is 15 days. Others treat the return day as free, which makes it 14. Switch the option above to match how you bill. A hire that starts and ends on the same day is always charged as one day.
How are weekly and monthly rates calculated?
Days are rounded up to whole periods: 15 days at a weekly rate is 3 weeks (every started week counts in full), and 31 days at a monthly rate is 2 months (30-day months). If you have a minimum hire period, set it above and the calculator will never charge fewer.
What if some items come back damaged or lost?
This calculator covers the hire charge only. Damaged or lost items are normally billed at replacement cost as a separate line, with no further hire charge once they are written off. RentalPro tracks broken and lost items per order and puts them on the invoice for you.
Does it save or send my figures anywhere?
No. The calculation happens in your browser and nothing is stored or uploaded. Refreshing the page resets it.
Is the calculator really free?
Yes — no signup, no limits. If you would rather not do this by hand for every order, RentalPro does the same calculation automatically and is free to use too.