Multiply your daily use by your trip days, then add a 20 percent buffer. That simple formula answers most data questions before you compare plans.
Start with how you use your phone abroad
Maps, messaging and email use little data. Video calls, streaming and photo backups use far more.
Check your phone's data settings at home to see your recent daily average. Then picture a typical travel day, not your quietest one.
Hotspot use changes the math. If a laptop or a partner shares your connection, plan for a larger daily amount.
Turn daily use into a plan size
Multiply your daily estimate by the number of trip days. Add the buffer for long transit days, navigation in new cities and surprise uploads. Round up to the next plan size rather than down.
Plan length changes the real price. A cheaper short plan can cost more per day than a longer one. Compare cost per day and per gigabyte, not just the headline figure.
Our cheapest eSIM picks and comparison pages help you line these up.
When unlimited data makes sense
Heavy users often look at unlimited eSIM plans. Most unlimited plans slow down after a daily allowance, so "unlimited" rarely means full speed all day.
Read the plan terms to find that allowance and the reduced speed. If your daily use stays under it, unlimited can remove the guesswork. If you stream or tether heavily, a large fixed plan may fit better.
Check validity and refunds before you buy
Validity usually starts at first connection. Install the eSIM before departure, but switch it on only when you land. Confirm this on the provider's pages before you rely on it.
Refund rules differ a lot between providers. Read them before checkout, especially if your travel dates could change.
Yesim is our Editor's Choice, and the Yesim review covers its details. We earn a commission from it. For setup steps, see how to choose an eSIM.
Want a number for your own trip? Try the data calculator.