Free UK broadband cost tool
Broadband cost calculator
Enter a deal's advertised price, contract length, setup fee and any cashback to see its true average monthly cost and cost per Mbps, so you can compare packages fairly, not just by headline price.
Free to use · No registration · Reviewed 2026-08-21
This is a general calculation using the figures you enter. It does not include scheduled mid-contract price rises, which many UK providers apply annually — check the deal's price-change terms separately.
Why the headline price is not the true cost
A broadband deal's advertised monthly price rarely tells the whole story. One-off setup fees push the real average cost up, while cashback pushes it down — but only if you actually claim it. Spreading every charge across the full contract term gives a true average monthly cost that is comparable between deals, even when their pricing structure is completely different.
How to use this calculator
- Step 1
Enter the advertised price
Use the exact monthly figure shown on the deal, including any packaged line rental.
- Step 2
Add the contract length
Most UK broadband deals run 12, 18 or 24 months — check the specific deal.
- Step 3
Include one-off charges
Add any setup or activation fee. Add cashback only if you are confident you will claim it.
- Step 4
Compare cost per Mbps
Enter the package speed to see cost per Mbps, useful when comparing packages of different speeds.
What this calculator does not cover
Scheduled mid-contract price rises: many UK providers increase the price during the contract, often each spring. This calculator uses the price you enter for every month of the term — check the deal's price-change wording separately, or read our guide to broadband price rises.
Post-contract pricing: the price usually rises once the minimum term ends. This tool calculates cost within the contract term only.
Address-specific availability: not every package is available at every address. Confirm availability before comparing costs.
Methodology reviewed by the BroadbandPicker editorial team on 2026-08-21.
Ready to compare deals at your address?
Run a few live deals through the calculator above, then compare true monthly cost — not just the advertised price — before you decide.
Availability and prices vary by address. A provider may pay us commission if you purchase after clicking through; this calculator's figures are not changed by commission.
Broadband cost questions
Why is my true monthly broadband cost different from the advertised price?
A one-off setup or activation fee spreads a small extra cost across every month of the contract, so the true average monthly cost is slightly higher than the headline price. Cashback works the other way: if you actually claim it, it lowers the true average monthly cost below the advertised price.
Does this calculator include VAT or line rental?
Enter the final price you would actually pay each month, including any packaged line rental. Business broadband prices are often advertised excluding VAT — add VAT to the monthly price before entering it if that applies to your quote.
What is cost per Mbps and why does it matter?
Cost per Mbps divides your true monthly cost by the package speed, which lets you compare a cheaper slow package against a pricier fast one on the same basis, instead of comparing headline prices for very different speeds.
Should I count cashback as reducing my monthly cost?
Only if you are confident you will actually claim it. Cashback is usually paid after a redemption process with a claim window, and unclaimed cashback is common. If in doubt, calculate the cost both with and without it.
How do I compare the total cost of two different broadband deals?
Run each deal through this calculator using its own price, contract length, setup fee and any cashback, then compare the true average monthly cost and total contract cost side by side, rather than comparing the two headline prices alone.
Sources and editorial notes
- Ofcom: Clear information before you buy broadband
- Ofcom: Get more from your broadband
- BroadbandPicker guide to broadband price rises
- BroadbandPicker review methodology and editorial policy
Last reviewed: 2026-08-21. We review this page when Ofcom guidance on price transparency changes.