Mobile Data Calculator for Travel: Find the Right eSIM Plan Size

Picking an eSIM plan comes down to one question: how many gigabytes will you actually use? Our free mobile data calculator answers it in under a minute. Open the data usage calculator, set your trip length, pick a travel style, adjust the hours you spend on each app away from Wi-Fi, and you get a total in GB, a plan size we recommend, and the real plans that fit your destination.

This article shows how the calculator works, what the four travel styles add up to over a week, and the mistakes that make people buy far too much or far too little data.

How the data calculator works

The calculator does the same sum you would do on paper, without the guesswork about how much each app uses:

1. Trip length. Drag along the bars or tap 3 days, 1 week, 2 weeks or 1 month. The bars grow day by day, so you see your data pile up over the trip.
2. Travel style. Four starting points fill in a typical day: Essentials, Explorer, Streamer and Remote. Pick the closest one, then adjust.
3. Activities. For each of nine activities, from maps to video calls, set how many hours a day you use it on mobile data. The style switches to Custom as soon as you change one.
4. Your estimate. The dial shows the total for your trip and the amount per day, then adds 15% room for surprises and rounds up to a usual plan size: 1, 2, 3, 5, 10, 15, 20, 30, 50 or 100 GB.
5. Your destination. Choose a country or region and the calculator lists the cheapest of our plans that cover your days with that much data.

How much data each activity uses

These are the figures the calculator uses: typical use per hour at default app settings, with HD video and normal-quality music. Your apps, settings and network can make real use lower or higher.

Activity	Typical use per hour	1 GB lasts about
Maps and navigation	10 MB	100 hours
Messages and email	20 MB	50 hours
Voice calls over apps	40 MB	25 hours
Web browsing	60 MB	17 hours
Music and podcasts	70 MB	14 hours
Social media	150 MB	7 hours
Short videos (TikTok, Reels, Shorts)	600 MB	1 hour 40 minutes
Video calls	600 MB	1 hour 40 minutes
Video streaming (HD)	1.5 GB	40 minutes

For the figures that app makers publish themselves, such as Netflix’s and Spotify’s, see our guide to how much data you need when travelling.

What the four travel styles use in a week

Here is what each starting style adds up to for a 7-day trip, before you change anything:

Travel style	A typical day	Per day	7 days	Our pick
Essentials	Maps, messages, a little browsing and music	about 190 MB	about 1.5 GB	2 GB
Explorer	Adds social media, short videos and a quick video call	about 800 MB	about 5.4 GB	10 GB
Remote	Hours of calls, email and browsing, some on a laptop	about 2 GB	about 14.3 GB	20 GB
Streamer	Social media, short videos and streaming	about 2.4 GB	about 16.2 GB	20 GB

Two things stand out. First, the gap between the lightest and heaviest style is more than tenfold, which is why “how much data do I need” has no single answer. Second, the jump from Essentials to Explorer comes mostly from video: half an hour of short videos and 15 minutes on a video call add about 450 MB a day.

Why we add 15% and round up

Real trips are messier than a typical day. A delayed train means an extra hour of browsing, a sunset means a video sent home, and an app may update in the background. The 15% buffer covers that, and rounding up to a usual plan size gives you a little more on top.

Running out on the last day, when you need maps to find the airport or a message from your airline, is worse than having a gigabyte left over. If the result sits between two sizes, take the larger one, especially for long trips.

Five mistakes the calculator helps you avoid

1. Counting Wi-Fi time. Only count hours on mobile data. Evenings on hotel Wi-Fi do not touch your plan.
2. Forgetting short videos. Scrolling Reels or TikTok on a bus feels like social media but uses about four times as much data.
3. Leaving autoplay on. Social apps play videos as you scroll. Their data saver settings stop that.
4. Ignoring the laptop. A laptop on your phone’s hotspot syncs files and installs updates. Our guide to using your phone as a hotspot covers how to keep that in check.
5. Buying for home habits. At home, video runs on Wi-Fi and mobile data alike. On a trip, most of it can wait for Wi-Fi.

An example: two weeks in Portugal

Say you are going to Lisbon and the Algarve for 14 days. You use maps for a couple of hours a day, message family, post on Instagram, listen to music on trains and FaceTime home for 15 minutes in the evening when the rental’s Wi-Fi is weak. That is close to the Explorer style, so the calculator shows about 11 GB for two weeks and suggests 15 GB once the buffer is added.

Choose Portugal as your destination and the calculator lists the plans that cover 14 days with at least that much data, cheapest first. Our Portugal eSIM guide covers networks and coverage there.

Check your estimate on the trip

An estimate is a starting point. After your first day, look at how much data you used in your phone’s settings, and compare it with the calculator’s per-day figure. If you are well over, the tips in the calculator (offline maps, paused photo backups, lower video quality, no autoplay) bring most people back on track. If a connection feels slow rather than short, our free internet speed test shows whether it is good enough for video and calls.

Your next step

Open the data usage calculator, set your days and style, and choose your destination to see the plans that fit. If you are not sure your phone supports eSIM, run our compatibility check first.