How prorated rent is worked out
Two steps. Divide the full monthly rent by the days in the month being split to get the daily rate. Then multiply that by the days the resident actually has the place.
The only real decision is which day count you divide by. Actual days gives a rate that moves month to month, so a day in February costs more than a day in March. A flat 30 keeps the rate the same all year. Whichever you pick has to be written into the lease and used every time — two residents at one property prorated two different ways is an argument you do not want.
Settle in writing whether move-in day counts. Counting the day the keys change hands is the common convention, and what this calculator assumes.
- Daily rate = full monthly rent divided by days in that month
- Prorated rent = daily rate multiplied by days occupied
- Pick actual days or a flat 30 and use the same one every time
- Say in the lease whether move-in day counts
When you actually need this
Mid-month move-ins are the obvious one, but not the only one. A resident who gives notice for the 12th owes twelve days of that final month, not the whole thing. A rent change landing mid-term splits the month at two rates, and so does a fixed term converting to month-to-month.
Charge the prorated amount as its own line on the move-in invoice rather than folding it into first month's rent. A resident who can see fourteen days at sixty dollars a day almost never disputes it. One who sees a lump number they cannot reconstruct always asks.
The mistake that costs you money
The expensive mistake is not the arithmetic. It is prorating the first month by hand and then never charging a full month on the right day afterwards, because the billing cycle got set from the move-in date instead of the rent due day. The first month is a one-off; the twelve behind it are the money.
In RentCaddie the proration is calculated when the lease is created and posted as its own visible line, and the recurring rent is scheduled separately on your rent due day.
A worked example
A resident takes the place on the 17th of a 30-day month. The full rent is $1,800, so they hold it for 14 days including move-in day.
- Full monthly rent
- $1,800
- Days in that month
- 30
- Daily rate ($1,800 divided by 30)
- $60 per day
- Days occupied
- 14
A 31-day month would give a $58.06 daily rate and $812.90 owed, which is why the day count belongs in the lease rather than being decided per resident.
Common questions
Should I divide by the actual days in the month or always by 30?
Both are used. Actual days is the more precise version and is what most residents expect when they check your math. A flat 30 keeps the daily rate the same all year. What matters more is that your lease says which one you use and you apply it the same way to everyone.
Does the day they move in count as a day of rent?
Usually yes, because that is the day they get the keys and the place stops being available to anyone else. State it in the lease so nobody has to guess. This calculator charges for whatever number of days you enter, so the convention stays yours.
Do I prorate the security deposit too?
No. A deposit is a fixed amount held against the tenancy, not a monthly charge, so it does not get split by days. Only rent and genuinely monthly charges, such as a utility share or a parking fee, get prorated.
What about a resident moving out partway through a month?
Same arithmetic on the last month instead of the first. If they already paid a full month, the difference becomes a credit settled alongside the security deposit rather than a second invoice.
These calculators are educational and are not legal, tax, lending, or accounting advice. Rules vary by state and by city, and your lease governs your own properties. Check your own requirements before relying on any number here.