Estimate gigabytes for this trip
Pick the country, trip length and daily habits. Japan is not France — the estimate applies a destination factor.
Destination
eSIM data calculator
Choose the country, then maps, chat, video and hotspot. A week in Japan is not a week in France.
WHY THE COUNTRY MATTERS
The same week is not the same gigabytes in Japan and in France.
Trip length and habits set the base. The destination multiplies it: maps-heavy cities with little free Wi-Fi need more; café-Wi-Fi Europe often needs less.
Light. Often 3–8 GB for a week once the country is set.
Reels and Stories dominate. Size up or go unlimited.
The spike. A few hours a day can justify 20 GB+ or unlimited.
Maps and messaging are cheap. Social video, cloud photo backup and a laptop on hotspot are not. A city break on transit apps can live on 3 GB; two weeks of Reels plus a work Mac will not. Toggle what you actually use, then pick the country — Japan, Korea and China sit above a French or Spanish city break for the same habits.
Buy the next allowance up, not the exact estimate. Fair-use unlimited can still throttle after a daily cap, so open the destination catalog and read the FUP before you pay. The button under the result goes to that country when you have selected one.
How the eSIM data calculator works
Pick a destination, set trip length, then toggle maps and chat, social video and laptop hotspot. The base is daily usage × days. A country factor then scales it: Japan, Korea and mainland China sit above a café-Wi-Fi week in France or Spain for the same habits, because maps, translation and IC-style apps run all day and free transit Wi-Fi is thin. The number is a planning range, not a lab measurement of your exact apps.
Hotel Wi-Fi is a bonus, not an input. If you will work from cafés on a Mac, turn hotspot on — that is where packs explode. Buy the next allowance up from the “buy at least” figure so photo backup and a missed Wi-Fi day do not zero the plan on day five.
Typical gigabytes for a week of travel
Maps, messaging and light mail: often 3–8 GB once the country is set. Add a couple of hours of social video a day and you are in the 10–15 GB band. Daily laptop hotspot or 4K-ish streaming belongs in 20 GB+ or fair-use unlimited. Two weeks is not twice as messy if hotel Wi-Fi covers evenings — but do not count on that in Japan, on a road trip, or in a hostel with a 50-device password.
Unlimited eSIM vs a 10 or 20 GB pack
“Unlimited” on travel eSIMs is usually a fair-use policy: full speed until a daily cap (often 1–3 GB), then throttle. That can beat a 10 GB pack if you stream every evening, and lose to a 20 GB limited plan if you only need maps. Open the destination page after the calculator and read the FUP next to €/GB. The result button sends you to that country when one is selected.
FAQ
eSIM data calculator FAQ
Why does the country change the estimate?
Same habits do not use the same gigabytes. Japan leans on maps, IC cards and translation with little free transit Wi-Fi. France or Spain often have hotel and café Wi-Fi. The simulator applies a destination factor on top of trip length and toggles.
How many GB for a week of maps and chat?
Usually 3–8 GB once you pick the country. Video and hotspot jump that to 15 GB or unlimited. Buy the next pack size up, not the exact estimate — photo backup and a missed hotel Wi-Fi day eat the margin.
Should I count hotel Wi-Fi in the simulator?
No. The estimate assumes cellular for maps, chat and the toggles you switch on. Hotel Wi-Fi is a bonus. If you will work from a laptop café-to-café, turn hotspot on — that is where packs blow up.
Is unlimited cheaper than a 20 GB pack?
Sometimes on Holafly-style daily FUP, sometimes not. Compare total price and the fair-use cap on the destination page. A 20 GB limited plan can beat “unlimited” that throttles after 2 GB/day.
How much data for two weeks in Japan?
Maps, translation and IC-card apps with little free transit Wi-Fi usually land around 10–20 GB for two weeks if you skip heavy video. Add Reels or a laptop hotspot and you want 30 GB or a fair-use unlimited plan. Run the calculator with Japan selected — the destination factor is higher than France or Spain.
Does phone hotspot use more data than the phone itself?
Yes, because a laptop or tablet streams at full window size, syncs cloud disks and keeps tabs alive. A few hours of hotspot can match a whole week of maps on the phone. Turn the hotspot toggle on in the calculator if you will work from cafés.
Should I buy the eSIM before I fly?
Yes, after the compatibility check succeeds. Buy, install on Wi-Fi, and keep the line off until you land if validity starts on first attach. Airport kiosk SIMs cost more per GB and waste the first hour of the trip.