How much mobile data do you need?

The short answer

If you are mostly on Wi-Fi at home and work, 10 - 20GB is often enough. If you stream on the commute, share hotspot or work from a phone, look at 40GB+ or unlimited.

Rough monthly guide

• 5GB - light use, messaging, maps, the odd video
• 10 - 20GB - social apps, music streaming, some video on the go
• 40 - 100GB - daily streaming, navigation, light hotspot
• Unlimited - heavy streaming, gaming downloads or regular hotspot for a laptop

These are starting points, not rules. Your last bill or your phone's data setting is the best evidence.

What uses data fast

• High-definition video and live TV apps
• Hotspotting a laptop or tablet
• Automatic cloud photo and video backup off Wi-Fi
• App updates downloading in the background
• Navigation with live traffic for long drives

What barely moves the needle

• Messaging and email
• Music streamed at normal quality
• Checking the weather, banking or tickets
• Short social scrolls with Wi-Fi nearby

Checklist

1. Open your phone settings and note last month's mobile data use
2. Add a buffer of around 20% if your month felt tight
3. Decide whether hotspot is occasional or every week
4. Only then shop for 5G, 40GB, unlimited and so on

Common pitfalls

• Buying unlimited "just in case" when 20GB would cover you
• Ignoring fair-use rules on some unlimited plans when hotspotting
• Assuming 5G always needs a bigger allowance - speed and allowance are different things
• Forgetting EU roaming and travel add-ons if you leave the UK often

Next step

Filter SIM only deals by the allowance you actually use. A slightly smaller plan with a clearer true cost usually beats an oversized one you never fill.