How much data do your apps really use? Maps, video, music, calls
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Before you buy a travel eSIM, it helps to know where your gigabytes actually go. Most people wildly overestimate messaging and web browsing and wildly underestimate video, which is why a plan that felt generous can vanish in an afternoon of hotel-room streaming, while another traveler barely dents 3 GB in two weeks of maps and chat. Here is a realistic, activity-by-activity breakdown so you can right-size your plan instead of guessing.
Video is the whole story
One number matters more than all the others: streaming video is, by a wide margin, the biggest driver of mobile data. According to Netflix's own figures, high-definition video runs up to about 3 GB per hour, while standard definition drops to roughly 0.7 GB, and 4K can hit 7 GB per hour. That single choice, HD versus SD, changes your daily total more than everything else combined. On a phone-sized screen standard definition looks perfectly fine, and switching to it is the fastest way to make a small plan last.
Everything else (music, maps, messaging, browsing) is smaller, often by an order of magnitude. Turn-by-turn navigation, the thing people worry about most on a trip, is one of the lightest things you can do.
How much data each activity really uses
These are rough, real-world figures for one hour of continuous use. Your exact numbers depend on quality settings, screen size and how chatty an app is, but the orders of magnitude are what matter:
| Activity | Approx. data per hour | Notes |
|---|---|---|
| HD video (1080p) | ~3 GB | The single biggest drain: drop to SD to save most of it |
| SD video (480p) | ~0.7 GB | Looks fine on a phone; about 4x lighter than HD |
| 4K video | ~7 GB | Rarely worth it on mobile data |
| Video calls (FaceTime, Zoom) | ~0.5–1.5 GB | Group and full-screen video use the most |
| Music streaming | ~0.07–0.15 GB | Higher on 'very high' quality; near zero if downloaded |
| Social scrolling (Instagram, TikTok) | ~0.1–0.3 GB | Autoplaying video pushes this to the top of the range |
| Turn-by-turn maps | ~0.005 GB | About 5 MB/hr, so a full day of navigation is tiny |
| Web & email | ~0.02–0.05 GB | Text and light images; near nothing |
| Messaging (WhatsApp, iMessage) | negligible | Text is nothing; photos and voice notes add up slowly |
Read that table and the pattern jumps out. An hour of HD video costs more data than a week of maps, messaging and email combined. If you never stream, even a modest plan will feel bottomless; if you stream daily, you simply need to plan for it.
- A two-hour SD movie is roughly 1.4 GB; the same film in HD is around 6 GB.
- A daily 20-minute video call home is about 0.2–0.5 GB a day, or a few GB over a fortnight.
- A full day of Google Maps navigation is well under 100 MB. Save offline areas and it's close to zero.
- An hour of music on standard quality is about 70–150 MB; download playlists on Wi-Fi first and it costs nothing on the road.
- Doom-scrolling social with autoplay on is the sneaky one: an hour can quietly match a short SD show.
Rule of thumb: if it's moving video, it's expensive; if it's text or audio, it's cheap; navigation is basically free. Manage the video and everything else takes care of itself.
Check what your own apps are doing
Averages are a starting point, but your phone can tell you exactly. Both platforms have a built-in per-app meter. Reset it at the start of your trip and check after a day or two to see your real pattern. On iPhone: Settings → Cellular, then scroll down to the per-app list (tap 'Reset Statistics' to zero it). On Android: Settings → Network & internet → SIMs → Data usage. You'll usually find one or two apps doing most of the damage, almost always something with video. For more ways to trim those numbers, see 10 ways to use less mobile data abroad.
So how big a plan do you need?
Once you know your habits, sizing is easy. As a rough weekly guide: around 1 GB/week if you stick to maps, messaging and the occasional web search; about 3 GB/week once you add social feeds and a bit of video; and 7 GB or more per week if you stream shows or take long video calls most days. Multiply by the length of your trip, then add a little headroom. It's far cheaper to buy slightly more or top up than to run dry mid-trip. Destination matters too: heavy map and translation use in an unfamiliar country adds up, so our how much data you really need in Japan guide walks through a real example. Still unsure? The Zwitchy data calculator turns your daily habits into a plan size in a few taps.
Does using Google or Apple Maps eat a lot of data?
No. Turn-by-turn navigation uses only about 5 MB per hour, so even a full day of driving barely registers. Download offline maps before you go and it costs essentially nothing.
How much data does an hour of Netflix or YouTube use?
About 3 GB per hour in HD and roughly 0.7 GB in standard definition, per Netflix's published figures. On a phone screen SD looks fine, so switching quality is the single biggest data saving you can make.
Is streaming music a problem on a small plan?
Not really. An hour of streaming is roughly 70–150 MB depending on quality, a fraction of video. Download your playlists over Wi-Fi before you travel and it costs nothing at all on cellular.
Do WhatsApp and iMessage use much data?
Text messages are negligible. Photos, voice notes and especially video calls are where messaging apps add up. A long video call can use 0.5–1.5 GB per hour, similar to a video stream.
How do I know how much I'll actually use?
Check your current per-app usage at home (iPhone: Settings → Cellular; Android: Settings → Network & internet → SIMs → Data usage), assume travel is a bit heavier on maps, and match that to a plan. The Zwitchy calculator does the maths for you.
