Can a cheaper monthly price cost more overall?

Yes. Setup costs, exit fees, handset balances and scheduled price changes can outweigh the monthly saving. Compare both options over the same period and include each cost once. The worked example uses invented prices, rather than a provider offer.

What does the cost-recovery month mean?

It is the first month from which switching has cost no more in total than keeping, and never becomes more expensive again within the selected period. A temporary early saving is not counted if a later price rise reverses it. No recovery month is shown when switching does not save overall.

Can I compare a phone contract with keeping my handset and a SIM-only plan?

Yes. Include the full monthly cost of each option, any new handset payment and any existing balance you must pay. An unavoidable cost belongs in both options, or neither if you are only comparing the difference. Do not count the same handset balance both upfront and in the monthly price.

What if I do not know a future price or cashback amount?

Use the prices stated in your contract or quote. You can change the figures to test a clearly assumed scenario, but the tool does not forecast prices. Include cash credits only when the amount, eligibility and receipt month are confirmed; leave uncertain cashback and vouchers out.

Calculator

Would switching broadband or mobile cost less?

Compare keeping and switching over the same period, including fees, known price changes and confirmed cash credits.

Keep: first monthly price (£)

Switch: first monthly price (£)

Compare over how many months?

Choose the same 1–60 full billing months for both options. Month 1 is the first month of the comparison.

Use your actual bill or quote, including VAT. Add known increases, fees and confirmed cash credits below. These are your entries, not live tariff offers.

Keep: fees, price changes and credits

Keep: upfront costs or handset balance (£)

Include balances payable for this option once. Do not also count them in the monthly price or exit fee.

Keep: exit fees (£)

Use the provider’s actual quote. Fees are counted in month 1.

Known price changes

Enter the new monthly price from that month, rather than the amount of the increase. Use increasing month numbers, starting at month 2.

Confirmed cash credits

Only include cash you qualify for and expect in a known month. Leave uncertain cashback and shopping vouchers out.

Switch: fees, price changes and credits

Switch: upfront costs or handset balance (£)

Include balances payable for this option once. Do not also count them in the monthly price or exit fee.

Switch: exit fees (£)

Use the provider’s actual quote. Fees are counted in month 1.

Known price changes

Enter the new monthly price from that month, rather than the amount of the increase. Use increasing month numbers, starting at month 2.

Confirmed cash credits

Only include cash you qualify for and expect in a known month. Leave uncertain cashback and shopping vouchers out.

How to make a fair comparison

Use the same full billing months for both options. Each month uses the entered price until a known change takes effect. Upfront costs and exit fees fall in month 1; confirmed cash credits fall in their receipt month. Totals use integer pence, with monthly averages rounded to the nearest penny.

Include lost discounts, equipment, delivery, overlap costs or a handset balance in the appropriate option without double-counting. If the same payment is unavoidable in either option, include it in both or leave it out of both. This worksheet does not decide whether a provider can charge an exit fee or prorate a partial month.

The comparison ends at the chosen month. A longer minimum term, outstanding handset debt or later price change can still matter after that point. Check the full commitment, service suitability and any social-tariff eligibility alongside the cost.

Ofcom recommends comparing the total cost, including setup fees, and checking contract length. Its current guidance explains how stated price changes should be presented for new contracts. Use your provider’s actual written terms and prices.

Approach and sources checked 24 October 2026. For practical switching steps, read our broadband cost guide or SIM-only and handset comparison. The worksheet calculates in your browser and does not send your entered costs to a supplier.

Frequently Asked Questions

Can a cheaper monthly price cost more overall?: Yes. Setup costs, exit fees, handset balances and scheduled price changes can outweigh the monthly saving. Compare both options over the same period and include each cost once. The worked example uses invented prices, rather than a provider offer.
What does the cost-recovery month mean?: It is the first month from which switching has cost no more in total than keeping, and never becomes more expensive again within the selected period. A temporary early saving is not counted if a later price rise reverses it. No recovery month is shown when switching does not save overall.
Can I compare a phone contract with keeping my handset and a SIM-only plan?: Yes. Include the full monthly cost of each option, any new handset payment and any existing balance you must pay. An unavoidable cost belongs in both options, or neither if you are only comparing the difference. Do not count the same handset balance both upfront and in the monthly price.
What if I do not know a future price or cashback amount?: Use the prices stated in your contract or quote. You can change the figures to test a clearly assumed scenario, but the tool does not forecast prices. Include cash credits only when the amount, eligibility and receipt month are confirmed; leave uncertain cashback and vouchers out.