How do I calculate a rent increase percentage in the UK?

The formula is: ((new rent − current rent) ÷ current rent) × 100. For example, if current monthly rent is £1,200 and the proposed new rent is £1,275, the calculation is ((£1,275 − £1,200) ÷ £1,200) × 100 = 6.25%. The calculator above handles this automatically for monthly, weekly, four-weekly, and fortnightly rents, converting all frequencies to a monthly equivalent for comparison. Most landlords in 2025/26 increased rent by between 3% and 9%, broadly in line with private rental inflation tracked by the ONS. An increase above 10% carries a higher risk of a First-tier Tribunal challenge.