Wi-Fi vs cellular data
Also known as: Wi-Fi vs mobile data, cellular data, mobile data vs Wi-Fi
Wi-Fi connects through a local wireless network and is typically unmetered, while cellular (mobile) data goes over your carrier and usually counts against a monthly allowance. Large transfers like photo backups and app updates are best left to Wi-Fi to avoid data caps.
- Wi-Fi is usually unmetered; cellular is capped
- Cellular works anywhere; Wi-Fi only in range
- Restrict backups and updates to Wi-Fi to save data
The practical difference
Wi-Fi uses a nearby router or hotspot and, at home, is normally unlimited. Cellular data uses your phone carrier’s network and most plans meter it, charging or throttling once you pass a monthly cap. Cellular works almost anywhere; Wi-Fi only within range of a network.
Because of the cap, phones treat the two differently. iOS and Android let you restrict heavy tasks — app downloads, cloud backups, and software updates — to Wi-Fi only, so they do not silently eat your data allowance.
Managing data use
On iOS, per-app cellular access lives in Settings > Cellular, and Settings > Photos can limit photo syncing to Wi-Fi. On Android, see Settings > Network & internet > Data usage and Data Saver. iCloud and Google Photos both offer a Wi-Fi-only upload option.
Freeing space by uploading media to the cloud can transfer many gigabytes, so doing it on Wi-Fi avoids a surprise overage on a cellular plan.