Calculating rent pro rata means adjusting the rent to reflect the exact number of days a tenant occupies a property.

Since the Renters’ Rights Act came into force on 1st May 2026, this has become an important compliance consideration.

With the strict legal cap of one month’s rent in advance, traditional methods of aligning payment dates are no longer allowed. For example, requesting or accepting “one month plus the remaining days” at the start of a tenancy is now a breach of the Tenant Fees Act 2019 (as amended) and counts as a prohibited payment.

If you want rent to fall on a specific monthly date, a pro rata initial payment is now the only compliant way to bridge the gap between the move-in date and the first full rental period.

1. The “initial rent” rule and the one-month cap
2. Situations where pro rata rent calculations are required
3. OpenRent’s pro rata rent calculator
4. Calculating maximum deposits pro rata

Take the guesswork out of compliant rent calculations and set up your tenancy the right way from day one.

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The “initial rent” rule and the one-month cap

Under the 2026 rules, you cannot request more than one month’s rent before the tenancy starts. If your tenant moves in on the 15th but they prefer rent to be due on the 1st of each month, you need to use a short initial rental period to align the dates.

Your first rent request (the “initial rent”) should cover only the “broken” days (e.g., from the 15th to the 30th). Once that period ends, the tenant then pays their first full month on the 1st. This effectively creates a one-off, shorter rental period at the start of the tenancy.

You cannot ask for the 15 days of the first month plus the following full month of rent in a single upfront payment. This would exceed the one-month cap and could result in an immediate civil penalty of up to £7,000.

Maximum rental periods post-Renters’ Rights Act

The Renters’ Rights Act has abolished fixed terms and capped the length of any single rental period. All tenancies now run on a rolling periodic basis, officially known as Assured Periodic Tenancies (APTs). A rental period cannot be longer than one calendar month.

You can still set shorter periods if needed, such as weekly arrangements. If you do, the maximum rent in advance you can request is capped at four weeks (28 days).

OpenRent’s APT agreements, available via Rent Now, use a standard monthly rental period, which is the most common setup and ensures maximum stability for both parties.

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Situations where pro rata rent calculations are required

There are two main reasons for calculating pro rata rent under the current 2026 framework.

• At the start of a tenancy: To align a payment date while staying within the statutory one-month rent in advance cap.
• When a tenancy ends mid-period: While a tenant’s notice to quit must legally align with the last day of a rental period, a Section 8 notice or a court-ordered possession date can fall on any day of the month.

In 2026, the law is strict: if a tenancy ends on any day other than the final day of a rental period (for example, due to a Section 8 notice or mutual surrender), you must refund any rent paid in advance for the days the tenant no longer occupies the property.

The statutory way to calculate the rent owed or the refund due is:

Multiply the monthly rent by the ratio of days the tenant occupied the property during that specific calendar month.

For example, if the monthly rent is £1,200 and the tenancy ends on the 10th day of a 30-day month:

1. Divide 10 by 30 to get 1/3.
2. Multiply 1/3 by £1,200.
3. The pro rata rent for that period would be £400.

Using this daily-rate calculation ensures your “initial rent” request or final refund is accurate to the specific month (accounting for months with 28, 30, or 31 days).

To make this even easier, use our pro rata rent calculator below to quickly work out the correct amount. This ensures your “initial rent” request or your final rent refund is fully compliant with the Renters’ Rights Act.

OpenRent’s pro rata rent calculator

Pro Rata Rent Calculator

Calculate compliant pro rata rent for partial occupancy or refunds.

Monthly Rent

£

Days Occupied

Total Days in Month

Pro Rata Rent Due:

£0.00

2026 Compliance: This calculation rounds down to the nearest penny to avoid exceeding legal rent caps.

You must take extreme care here: “Occupancy” for a refund calculation must be measured from the start of the specific rental period, not the start of the calendar month.

For example, if a tenant moves out on the 17th of May, but their monthly rental period actually runs from the 4th of each month to the 3rd of the next, they have only occupied the property for 14 days of that period, not 17.

Calculating maximum deposits pro rata

The pro rata method also determines your deposit caps. Tenancy deposits are capped at 5 weeks’ rent, while holding deposits are limited to one week’s rent.

To calculate a “week’s rent” legally, you must use the following formula: (Annual Rent ÷ 52).

To keep things simple and ensure you stay compliant, we have created a calculator that can help you find the maximum amounts for both deposits. 

Ensuring your deposit is not even £1 over this limit is necessary to avoid rendering your Section 8 notices invalid in the future.