How much eSIM data do you need? Use your real usage
Do not choose an allowance from a generic activity chart. Measure a recent period on your phone, calculate your average per day, multiply it by the trip length, then add a buffer that reflects how certain you are. The calculator below uses only the numbers you enter.
Measure a period that looks like your trip
A work week with video calls is a better sample for a work trip than a quiet weekend at home.
Settings › CellularApple shows mobile-data use by app for the current period.Settings › Network & internet › SIMsGoogle shows the total mobile data at the top.App data usageSelect the period and review which apps used the data.Settings › Connections › Data usageSamsung places mobile-data totals and controls in this section.Calculate a transparent allowance
Enter one measured period. The result is your measured daily average multiplied by the trip length and selected buffer.
Find what is driving the total
Use the app list on your phone. The largest entries deserve attention before smaller background services.
Video and calls
Check streaming and meeting apps in your measured period. Lower quality inside the app when needed.
Photo and file uploads
Pause automatic mobile uploads if you want them to wait for Wi-Fi.
Hotspot devices
A connected laptop can download updates or sync files through the phone.
Maps and messages
Keep the services you need, then download supported offline content before departure.
Reduce data without losing the useful parts
Use the phone controls that target background activity, then keep navigation and communication available.
Data-planning questions
How can I estimate travel data without guessing?
Where can I see mobile data use on iPhone?
Where can I see mobile data use on Pixel?
Does hotspot use count against an eSIM allowance?
Should I buy unlimited data instead of calculating?
Know your allowance?
Compare current plans and coupon conditions, then choose a validity period and data amount that cover your calculated requirement. The directory currently contains 48 stored coupon codes across 33 published providers.