How to use the price increase calculator

Enter the old price, the new price and how often you pay it. The calculator subtracts the old figure from the new figure to show the pound change. It then divides that change by the old price to show the percentage difference. A negative figure means the price has gone down.

The yearly difference converts a weekly price into 52 payments and a monthly price into 12 payments. It is a straightforward planning view for bills, rent add-ons, subscriptions, insurance renewals, streaming services and many other regular costs. It assumes the price stays the same for the whole year.

Pounds and percentage answer different questions

A small pound rise can be a large percentage change when the original price was low.

Use the price you actually pay

Include mandatory fees, but keep one-off setup costs separate from a recurring bill.

Discounts may end

Check whether a new price includes an introductory offer or a discount due to expire.

Checking a bill increase

Read the supplier's notice carefully. Some price changes are caused by a change in usage, a discount ending, an annual renewal, a change to payment method or a separate fee, rather than the advertised base price. This calculator compares the two amounts you enter; it does not decide why they changed.

For electricity, compare both unit rate and standing charge rather than using only a single monthly total. For subscriptions, use the Subscription Cost Calculator if you want to add several services together. For a shopping discount or markup, the Percentage Calculator may be a quicker fit.

Keep the periods comparable

When the price period changes, make the figures comparable before entering them. Divide an annual cost by 12 before comparing it with a monthly bill, or compare two annual prices directly. This avoids a misleading percentage simply because one figure covers a longer period than the other. Treat one-off setup fees separately from a regular price.

Keep a note of the date the new price starts. A provider may charge part of one period at the old price and part at the new price, so the first bill after a change can look different from this full-period comparison.