What is the rent inflation calculator and what does it show?

The August rent increase calculator lets UK landlords and tenants work out the impact of a proposed rent change in seconds. Enter your current rent and either the proposed new amount or a percentage increase, it will instantly show the new rent per period, the pound increase per period, the percentage change, the additional annual cost, and the new total annual rent. Optionally enter your proposed effective date, notice service date, and last increase date to check whether your Section 13 Form 4A notice satisfies the two-month notice requirement and the 12-month rule under the Renters' Rights Act 2025. The calculator covers monthly, weekly, four-weekly, and fortnightly tenancies, and converts all frequencies to a monthly equivalent for consistent comparison. It is free to use and requires no sign-up.