Free planning tool
How much eSIM data will you need?
Turn your own measured mobile-data use into a trip budget. Add only the extra use you expect, choose a reserve and compare that estimate with actual plan allowances.
No account needed. Start blank or load a fictional example. This calculator also works without JavaScript.
Your trip data budget
Start with your own sample.
No consumption is assumed. You can load the clearly fictional example to see how the calculation works.
An estimate of data needed, not an included allowance or a guarantee. Check each plan’s coverage, validity and activation rule separately. Phone counters and the plan’s reported usage may differ.
Measure first
Use a sample that represents your trip.
Read mobile-data use for one SIM and a known date range. Use that same period for the sample days. Wi-Fi traffic is outside this sample; mixing several lines or a different date range makes the daily average misleading.
Apple explains where to find cellular use by app and the selected data line in its iPhone and iPad data-usage reference. Google’s Pixel mobile-data guide covers the usage period and app breakdown. Device menus vary; check the settings on your model.
A phone’s counter is a planning input. The provider may meter usage differently, so compare the plan’s reported allowance and usage before deciding that data is exhausted. A missing or old reading remains uncertain.
Adjust for what will change
A quiet week at home may not represent a trip with video calls, uploads or a laptop sharing the connection. Add your own estimate for that extra use across the whole trip. If the same activity is already represented in the sample, avoid counting it again.
Changing app quality, offline downloads, background updates and Wi-Fi availability can change consumption. No single per-app rate or daily GB amount fits everyone. If your sample is unrepresentative, measure again rather than treating extra headroom as proof.
The arithmetic
See exactly what the budget includes.
(measured GB ÷ sample days × trip days + additional trip GB) × (1 + headroom % ÷ 100)
Fictional example: 2.1 GB over 7 days gives 0.3 GB per day. For 14 days, that is 4.2 GB. Add 1 GB of extra use for the whole trip: 5.2 GB. A chosen 20% reserve adds 1.04 GB, giving 6.24 GB. These values illustrate the calculation; they are not typical use or a listed plan.
Use GB consistently. If your counter reports decimal MB, divide by 1,000 to enter GB. GiB is a different unit: 1 GiB is about 1.074 GB. Check the counter’s stated unit instead of assuming they match.
Before choosing
Data is one part of the plan.
- Coverage. Check every destination against the plan’s actual covered-country list. A routing location or regional name does not establish coverage.
- Validity and activation. Compare your dates with the term and what starts it. More data does not automatically mean a longer period of access.
- Hotspot and speed policy. Check the selected plan’s reported sharing support and any usage or speed conditions before making a laptop depend on it. Follow the eSIM hotspot checks before sharing the connection.
- Device and messages. Confirm your exact device’s eSIM support and carrier-lock state. Data connectivity alone does not establish calls or carrier SMS.
Compare current eSIM plans
Read actual coverage, allowance, validity and reported features.
Plan a multi-country trip
Check every stop, including a return visit, against the plan.
Prepare and install an eSIM
Check the device and activation policy before using delivered details.
Understand data-only eSIMs
Keep internet messaging and carrier SMS entitlements separate.
Manufacturer references checked 22 October 2026. This is a planning calculation and documentation check, not a handset, network or paid-plan test.