Rent Increase Calculator

How to calculate a rent increase

A rent increase can be calculated by applying a percentage to the current rent, or by determining the percentage change between an old and a new amount.

To find the new rent when you know the percentage increase, multiply the current rent by (1 + percentage). For example, a 5% increase on £1,000: £1,000 × 1.05 = £1,050.

To find the percentage when you know the new amount, divide the difference by the original rent, then multiply by 100. For example, moving from £1,000 to £1,050 is a difference of £50. £50 ÷ £1,000 × 100 = 5%.

Percentage increase vs £ increase

Landlords often review rent in line with inflation (such as CPI) or broader market trends, which are usually expressed as percentages. However, tenancies are paid in pounds, and small percentages can translate to significant cash amounts for tenants.

Some tenancy agreements contain specific rent review clauses that dictate exactly how an increase must be calculated — for example, stating it must be aligned with the Retail Prices Index (RPI) or specifying a maximum percentage cap.

Monthly vs annual impact

A small increase to a weekly or monthly payment compounds significantly over a year. A £50 per month increase adds £600 to the property's annual gross rental income.

When evaluating the financial performance of a property, this increased annual income will improve the property's gross yield. You can see the effect of this using our rental yield calculator.