Prorated rent

What it means

Prorated rent is a partial month's rent, charged when a tenant occupies the property for only part of a rent period — typically at move-in or move-out.

A tenant taking possession on 19 March does not owe a full month for March. They owe the days they have. Proration is the arithmetic that turns a monthly rent into a daily one and multiplies it by the days occupied.

There are two accepted methods, and the difference between them is small but real:

The 30-day method. Monthly rent divided by 30, regardless of the actual month. On the canonical unit at $2,400, that is exactly $80.00 a day. Simple, stable across months, and slightly favourable to the landlord in February and slightly unfavourable in the 31-day months.

The actual-days method. Monthly rent divided by the number of days in that specific month — $2,400 ÷ 31 = $77.42 in March, $2,400 ÷ 28 = $85.71 in February. More precise, less predictable.

A third variant, the banker's year, divides annual rent by 365: $28,800 ÷ 365 = $78.90 a day. It is the fairest across a full year and the least common in residential leases.

Whichever you pick, the lease agreement should name it. A few states specify a method by statute; most leave it to the contract, and where the contract is silent, courts tend to prefer actual days.

Why it matters

Proration is small money handled often, which makes it a reliable source of disputes and reconciliation problems out of all proportion to the amounts.

The individual sums are minor: the difference between $80.00 and $77.42 a day over thirteen days is $33.54. But the same calculation happens at every move-in, every move-out, every mid-month rent change and every rent abatement — and each one that is done differently leaves a ledger that does not reconcile.

The bigger exposure is downstream. The daily rate is what a pay or quit notice uses to state arrears, and several states void a notice that overstates the amount. It is what the security deposit itemization uses to charge unpaid final-month rent. It is what a holdover claim is built on. Getting the daily rate wrong at move-in means it is wrong in every document that follows.

There is also a timing benefit landlords overlook. Prorating the first month and starting the full cycle on the first of the following month puts every unit on the same due date — which is worth more administratively than the few dollars either method saves.

How it works in practice

Fix the method in the lease and use it everywhere.

Move-in mid-month. A tenant taking possession on 19 March, with the lease running to the following March, pays for 13 days of March and then $2,400 on the first of each month.

Move-in proration, 30-day method	Amount
Monthly rent	2,400.00
Daily rate — 2,400.00 ÷ 30	80.00
Days occupied, 19–31 March	13
Prorated March rent	1,040.00
First full month, 1 April	2,400.00

Under actual days the same period is 13 × $77.42 = $1,006.46. Both are defensible; only one should appear in your lease.

Move-out mid-month. The same arithmetic in reverse, and the same trap: possession ends when keys and the unit come back, not when the tenant's last box leaves. A tenant vacating on 8 April owes 8 days — $640.00 — and the remainder of any rent already paid is refunded, usually through the security deposit settlement rather than separately.

Which month to prorate. Collecting a prorated first month plus a full month at signing is common where the move-in is late in the month; so is charging the full first month and prorating the second. Both are lawful. Pick one and write it down, because a tenant who expected the other will treat the difference as a surprise charge.

Rent changes mid-period. A rent increase effective on the 15th is prorated the same way: old rate for the first part, new rate for the rest, both at their own daily figures.

Common mistakes

• Mixing methods. 30-day at move-in and actual days at move-out produces a ledger that does not tie out and an arrears figure you cannot defend.
• Not stating the method in the lease. Where the contract is silent, the tenant's preferred method is often the one a court applies.
• Counting the wrong days. Whether the move-in day itself counts should be stated; the usual convention is that it does.
• Prorating from the lease date rather than possession. Possession is what is being charged for.
• Forgetting the deposit is not prorated. The full deposit is due regardless of a partial first month.
• Rounding. Rounding a daily rate to the dollar before multiplying compounds the error over a 13-day period.

How BareBones PM helps

Proration goes wrong because it is calculated by hand, in different ways, at moments when everyone is busy.

BareBones PM stores the rent and the proration method on the lease, and derives the daily rate from them — so the $80.00 used at move-in is the same figure used in a move-out settlement, an arrears calculation and a deposit itemization months later.

Partial periods post to the ledger as their own charges with the day count shown, rather than as an unexplained amount that differs from the monthly rent. A year later it is still clear why March was $1,040.00.

Because arrears are computed from the same daily rate, the figure that goes into a notice is the one the ledger supports, which is what keeps the notice defensible.

For how the ledger handles partial periods and adjustments, see The rent ledger.