In this article
Pro rata means in proportion. If you pay for a whole month but use only part of it, you pay the same share of the amount as the share of the month you use. The method is the same for rent, salary, a gym fee or a software plan: find the amount for one day, then multiply by the days that count.
The formula, step by step
- 1Find the daily amount₹30,000 ÷ 30 days = **₹1,000** a day.
- 2Multiply by the days charged₹1,000 × 12 = **₹12,000**.
- 3Find the share of the period12 ÷ 30 = **40%**.
- 4Find what is left₹30,000 − ₹12,000 = **₹18,000**.
The tool shows the pro-rated amount, the amount per day, the remaining amount and the share of the period.
How much for different numbers of days
| Days charged (out of 30) | Pro-rated amount | Share of the period |
|---|---|---|
| 5 | ₹5,000 | 16.7% |
| 10 | ₹10,000 | 33.3% |
| 12 | ₹12,000 | 40.0% |
| 15 | ₹15,000 | 50.0% |
| 20 | ₹20,000 | 66.7% |
| 25 | ₹25,000 | 83.3% |
Same ₹30,000 and a 30-day period. The amount grows in a straight line with the days.
Each day adds ₹1,000 here. Halving the days halves the amount.
The hidden choice: how many days in the period?
A month has 28 to 31 days, and a contract may say to use the real number of days, or a fixed 30, or even the working days. The same ₹30,000 and 12 days give different amounts:
| Days used as the divisor | Amount per day | Amount for 12 days |
|---|---|---|
| 28 days | ₹1,071.43 | ₹12,857.14 |
| 30 days | ₹1,000.00 | ₹12,000.00 |
| 31 days | ₹967.74 | ₹11,612.90 |
The difference between 28 and 31 days is ₹1,244.24 for the same 12 days. Neither is wrong. The agreement decides.
Where pro rata is used
- Rent and deposits, when a tenant moves in or out mid-month.
- Salary, for a joiner or leaver who works part of a month.
- Subscriptions and memberships, for a plan started or cancelled partway through.
- Fees and insurance, where cover or a service covers only part of a term.
- Annual amounts, such as a yearly plan used for a number of days.
- ₹30,000 for 12 of 30 days
- Joiner, leaver or tenant
- Per day: ₹1,000
- ₹12,000 plan used for 100 of 365 days
- Set the period to 365 days
- Per day: ₹32.88
The calculator does not care about the length of the period. Enter the days of the full period, whether 30, 31 or 365.
The pro-rated amount and the remaining amount always add up to the full amount.
A short routine
- Write down the full amount and the length of the full period in days.
- Count the days to be charged, and decide whether the first and last days count.
- Agree the divisor (actual days, 30 or working days).
- Run the calculator and check that the amount and the remainder add up.
- Round to the nearest rupee only at the end.
Questions people ask
How do I calculate pro-rata pay?
Divide the full amount by the number of days in the full period, then multiply by the days to be paid. For 30,000 a month and 12 days out of 30, it is 30,000 ÷ 30 × 12 = 12,000.
Should I divide by 30 or the real days of the month?
It depends on your contract or policy. The real days give a slightly different amount in months of 28, 29 or 31 days. Agree the method first.
How do I pro-rate an annual amount?
Enter the annual amount, 365 days (or 366 in a leap year) as the full period, and the days to charge. A 12,000 plan used for 100 days comes to about 3,287.67.
What does the remaining amount mean?
It is the part of the full amount for the days that are not charged. With 30,000 and 12 days charged out of 30, the remaining amount is 18,000.
Can days to charge be more than the full period?
No. The tool asks for a number between 0 and the length of the full period.
Is the pro-rata amount the same as a refund?
Not always. A refund may also include fees or a minimum charge. For a daily figure alone, you can also use the Time Calculator or the Date Difference Calculator to count the days.