The best starting point is your last three bills or your provider’s app. Look for mobile data used, not the data allowance you bought. Phone settings can help too, but check that their dates match your billing period.
Start with your busiest normal month
If you used 3 GB, 4 GB and 6 GB, a 10 GB plan gives you some room. This is an example, not a rule: a new commute, lots of video or working away from Wi-Fi could change your needs.
Know what uses the allowance
Video, large downloads and sharing your connection with a laptop can use much more data than messages. Download films, maps and music over Wi-Fi when that suits you. Your recent use is the best guide to the allowance you need.
Compare the plan, not just the number
Check calls, texts, coverage, use abroad, whether you can share data with other devices, and how long you must keep the plan. A travel data pack may not include a UK phone number or ordinary calls. Our SIM comparison separates those options.
Make room to change
A short plan can be useful while you learn your usage. Check how to cancel or change the allowance, and whether an advertised discount ends after a few months. Use SIM comparison to keep the terms side by side.
Use Wi-Fi habits, not a fixed hours chart
An hour of video can use very different amounts of data depending on quality and the app. Check your actual usage instead of relying on a universal GB-per-hour estimate. If you share data with a laptop, include its downloads and updates too.
See 5 GB plans, 10 GB plans or 50 GB plans. Check coverage before choosing purely on allowance.
Reviewed 29 October 2026 · Here4Mobiles