Estimate your data before you travel.

The estimator adds daily hours × per-hour usage for maps, social, music and video, multiplies by the number of travel days, adds about 50 MB per day of background use, then adds a 20% buffer. Video tiers: data saver about 300 MB/hour, standard about 700 MB/hour, HD about 1.5 GB/hour. Maps are about 10 MB/hour, social about 150 MB/hour and music about 60 MB/hour.

Change video quality first: it usually moves the total more than adding a day of maps. Tethering a laptop is extra hours in the same buckets, not a separate free pool. The 20% buffer is for updates and a missed hotspot, not a licence to stream all evening.

Example 1: a 7-day trip with 1 hour of standard video, 1 hour of maps and 1 hour of social media a day is about 6.4 GB including background; with the 20% buffer that is about 7.6 GB, so round up to a 10 GB package.

Example 2: a 14-day trip with 2 hours of HD video, 1 hour of music and 2 hours of social media a day comes to about 48 GB; with the buffer it is close to 58 GB, which suits a top-up or unlimited plan. Example 3: the same 7-day trip with video off and maps plus social only is about 1.5 GB before the buffer and about 1.8 GB after; round up to a 3 GB package. Offline maps cut the maps line further.

Use it before buying a travel eSIM or local data package, to decide whether an unlimited plan is worth it, and to compare whether a carrier's allowance is enough.

Run it twice: once with hotel Wi-Fi assumed for evening video, once without. Destination internet guides on this site compare eSIM, SIM and Wi-Fi eggs; this page only turns hours into gigabytes.

Common mistakes include buying a small package while streaming HD for hours, ignoring autoplay, system updates and photo sync, treating the throttling threshold of an unlimited plan as truly unlimited, and forgetting that tethering counts against the same allowance.

Another is estimating only the phone and then sharing a hotspot with a laptop that backups photos. Cloud backup and OS updates can spend a gigabyte overnight on hotel Wi-Fi — or on the eSIM if Wi-Fi is captive.

Video tiers reference publicly published per-hour streaming figures, such as those in the Netflix Help Center, rounded to common mobile levels. Maps, social and music use about 10, 150 and 60 MB/hour, plus about 50 MB/day background. Actual usage varies with quality, autoplay, caching, network and app settings, so treat the estimate as a starting point for buying a package.

The model does not know a specific carrier’s fair-use cap, and it does not measure your phone. Recalculate if you add a work VPN or a day of video calls.