RentifyNow

Rent change calculator

See what a proposed rent increase or decrease means: the difference per period, the percentage change and the total over the periods you choose.

Free, no login. Inputs stay in memory in this page; they are not saved or uploaded.

Compare the same period and currency

Use plain numbers with a decimal point, without currency symbols or thousands separators. Changing currency or period clears both rents. No conversion is applied.

Zero is allowed, but has no defined percentage change.
Use the same period and currency as the old rent.
1–10,000 whole periods. For monthly rent, 12 means 12 months. Leave blank for just the per-period change.

How to calculate a rent increase percentage

Subtract old rent from new rent to find the amount of change. Divide that difference by old rent, then multiply by 100 for the percentage. The old rent is the reference point: an increase from 1,000 to 1,050 is 5%, while a decrease from 1,050 to 1,000 is about 4.76%.

For example, GBP 1,000 changing to GBP 1,050 per month adds GBP 50 per month: (1,050 − 1,000) ÷ 1,000 × 100 = 5%. Across 12 months at those amounts, old outlay is GBP 12,000 and new outlay is GBP 12,600, a nominal additional GBP 600.

Decreases, zero rent and projection limits

A negative difference is a decrease. Equal rents give zero change. If old rent is zero, the amount difference still works, but the percentage is not defined, including when both rents are zero. This calculator accepts amounts to two decimal places and rounds percentages to two decimal places.

The projection multiplies the difference by your chosen number of whole periods. It assumes the new amount applies for every period. It does not compound increases, convert weeks to months, prorate dates, account for leap years or daylight saving time, estimate inflation, or include fees, tax or currency conversion. Compare like-for-like rent amounts yourself.

This is arithmetic, not a rent-limit or legality check. It does not determine permitted increases, notice periods or whether a proposed change can take effect. No legal rules or automatic rent changes are applied.

From a comparison to rental records

After comparing your figures, use the property management guide to see how RentifyNow organizes property records and rental work. For purchase costs and income assumptions, try the rental yield and cash-flow calculator.