What uses the allowance
Map tiles, photo uploads, short video, translation and app updates can turn a light day into a heavy one. Download offline material and postpone large backups to trusted accommodation Wi-Fi when you want a smaller plan.
Hotspot changes the answer
Tethering a laptop or another traveller adds devices and background traffic. Confirm the live plan allows hotspot use, then size for the shared devices rather than only the phone that holds the eSIM.
Avoid false precision
A calculator cannot know future video quality, automatic backups or Wi-Fi reliability. Use the estimate as a band, compare top-up rules and choose a plan whose expiry covers the complete trip. Live allowance and fair-use terms belong to the provider page.