The quick answer
If you’d rather not touch a slider, these cover most people, per week of ordinary travel:
- 1–3GB— maps, messaging, email and a few searches a day. The classic “I just need to find the restaurant” trip.
- 5–10GB — the above plus social media, photo uploads and general browsing on the move. This is where most people land.
- 20GB or unlimited — video calls home most days, streaming, or tethering a laptop for work.
Two things shift those numbers more than anything else: how much you’re on hotel wi-fi in the evenings, and whether video is involved at all.
What each app actually uses
These are the rates behind the calculator. They’re mid-range figures rather than worst cases — quoting the heaviest possible number would sell a bigger plan and be wrong most of the time.
| Activity | Per hour | Worth knowing |
|---|---|---|
| Maps and navigation | ~5 MB | Cheaper than almost anything else — download offline maps and it's near zero. |
| Messaging and email | ~15 MB | Text is tiny. Sending photos and voice notes is what moves the number. |
| Browsing and searching | ~60 MB | Image-heavy sites and news apps sit at the top of this range. |
| Social feeds | ~250 MB | Autoplaying video is the cost, not the photos. Turning autoplay off roughly halves it. |
| Music streaming | ~70 MB | At standard quality. High quality can be three times that. |
| Video calls | ~700 MB | Varies enormously with resolution; an audio-only call is a fraction of it. |
| Video streaming | ~1.5 GB | SD is nearer 700 MB, HD comfortably past 3 GB. The single biggest consumer. |
The spread is the point: an hour of navigation costs about 1/300th of an hour of video. Sizing a plan is mostly a question of how much video you’ll watch on mobile data, and almost nothing else.
Three worked examples
| Traveller | A typical day | Per week |
|---|---|---|
| City break | 2h maps, 1h messaging, 30m browsing | ~0.6GB |
| Everyday traveller | 1h maps, 1h messaging, 1h social, 30m browsing | ~2.3GB |
| Working remotely | 2h video calls, 2h browsing, 1h social, 2h music | ~13GB |
Note how far apart the first and last rows are: the same week needs a 1GB plan or a 20GB one depending almost entirely on whether video is in the mix. Every figure here is what the calculator above returns for those inputs.
Why people get this wrong
The usual mistake is reasoning from the home phone bill. A domestic plan covers all your usage, including hours of video on the commute. A travel plan covers only what happens away from wi-fi— and on most trips the hotel, the café and the rental all have wi-fi, so the eSIM carries the gaps between them.
The second mistake is assuming photos are expensive. Taking them costs nothing; only uploadingthem does, and that usually happens on wi-fi overnight. If your phone backs up to the cloud automatically, it’s worth setting that to wi-fi only before you go.
When unlimited is the cheaper option
Above roughly 20GB for a trip, an unlimited plan is generally cheaper than the equivalent fixed allowance, and it removes the risk of running dry.
Read the fair-use line first, though. Most unlimited travel plans run at full speed up to a daily allowance and then slow down for the rest of the day — we state that allowance and the reduced speed on every plan that has one, because “unlimited” on its own doesn’t tell you what you’re buying.
If you run out mid-trip
Nothing dramatic happens: data stops, and you aren’t billed for overage. You can top the line up or buy another plan — but that needs a connection, so do it from wi-fi, or before the last of the allowance goes.
Check the balance every few days rather than at the end. Running out on the way to the airport is the one moment it genuinely matters.
Making a smaller plan go further
- Download offline maps for the city before you go. This alone covers the single most common travel use.
- Turn off video autoplay in your social apps. It is the largest silent consumer on most phones.
- Set cloud photo backup to wi-fi only, along with app updates.
- Download music and shows before you fly, on your own broadband.
- Use audio instead of video for the daily call home — it costs roughly a tenth as much.
Know your size? Jump straight to 3GB, 5GB, 10GB or unlimited plans — or browse by countryto see what’s available where you’re going.