How much data do I need for international travel? Start with your own phone.

1. Use your history—not somebody else's itinerary

Your phone already contains the most relevant evidence. Choose a recent period that resembles the trip: ordinary commuting may be a reasonable baseline, while a week spent at home on Wi-Fi is not. Exclude one-off events only when you are confident they will not happen abroad.

Worked example

Suppose your phone shows 6.4 GB over 30 representative days. That is about 0.21 GB per day. For a 12-day trip, the baseline is about 2.6 GB. Adding a 25% buffer brings the estimate to roughly 3.2 GB, so a 5 GB plan gives more breathing room than a 3 GB plan.

Do not subtract hotel Wi-Fi unless you are comfortable depending on it. Public and hotel networks can be slow, unavailable or unsuitable for sensitive activity. Treat trusted Wi-Fi as a way to preserve your allowance, not as the only thing keeping the trip online.

2. Find cellular usage on an iPhone

Open Settings → Cellular or Settings → Mobile Data. Apple shows cellular use by app and a total for the current statistics period. The period does not necessarily reset every month, so scroll to the bottom and check the last reset date before using the total.

If the statistics cover several months, reset them at the start of a normal week or billing cycle and measure again. Do not reset immediately before recording the old result. Apple notes that the carrier may measure usage differently; the carrier's account is the reference for billing, while the phone is useful for planning and finding high-use apps.

3. Find mobile usage on a Pixel or another Android phone

On a current Google Pixel, open Settings → Network & internet → Internet, tap the settings icon beside the carrier, then open app data usage. You can select a period and see which apps used the connection. Other Android manufacturers may place the same information under Data usage, Mobile network or SIM manager.

Android can also set a warning or a hard data limit. A hard limit may turn mobile data off automatically, which can be useful but risky if it interrupts navigation or a ride-hailing app. A warning set below the eSIM allowance is the safer starting point for many travelers.

4. Identify what can change the estimate

Messaging, email, browsing and map lookups usually do not create the same risk as sustained video, large downloads, cloud uploads or laptop tethering. But there is no universal per-hour number: app settings, media quality, device behavior and what you actually view all matter.

Netflix's own settings demonstrate the size of the video-quality gap: it lists up to 0.3 GB per hour at Low, up to 3 GB per hour for HD under High and up to 7 GB per hour for 4K. Those are Netflix-specific maximums, not estimates for every video service. The lesson is that “I watch video” is not enough information; quality and duration belong in the plan.

5. Translate the estimate into a plan size

Providers sell allowances in steps, so choose the first available size above your buffered estimate. Avoid buying exactly the calculated amount: the phone's counter and the provider's meter can differ, and travel days are rarely identical.

These are planning profiles, not promises that a given allowance lasts a specific number of days. Your measured baseline remains the deciding evidence.

Also compare top-up rules. A slightly smaller plan can be reasonable when you can add data instantly at a fair price without reinstalling the eSIM. If top-ups are unavailable, expensive or require a new profile, buying more buffer at the start may be simpler.

6. Reduce predictable data use before departure

• Download offline maps for the complete destination area on trusted Wi-Fi.
• Download tickets, hotel details, translation packs, music and entertainment.
• Pause photo/video backup over cellular and automatic app updates.
• Change streaming apps from automatic or maximum quality to a data-saving option.
• Turn off cellular access for apps that do not need to work during the trip.
• Tell a tethered laptop that the hotspot is a metered connection.

On iPhone, Low Data Mode restricts background network use, reduces streaming quality and pauses automatic downloads and backups in supported services. On Pixel, Data Saver limits background mobile data for most apps while allowing active apps to use it. Both modes can change app behavior, so give essential messaging, navigation or authentication apps the access they require.

7. Check the allowance during the trip

Record the phone's counter immediately before the travel line starts, then compare the device and provider app after the first full day. If the pace is higher than planned, identify the app—not just the total—and change its settings early.

Do not delete an installed eSIM simply because the data counter looks wrong. Some profiles cannot be reinstalled without provider help. First check which line is carrying cellular data, whether the provider dashboard has updated and whether a top-up is available.

Final data-sizing checklist

Common questions

Is 5 GB enough for a week abroad?

It can be enough for a light or moderate user, but the number of days alone cannot answer it. Apply the formula to your own history and account separately for video, hotspot use and cloud backup.

Does GPS use mobile data?

GPS positioning itself does not require an eSIM, but map downloads, place searches, live traffic, transit information and route changes can use data. Downloading an area reduces dependence on the connection but also removes some live features.

Should I buy unlimited data?

Only when your measured needs and the plan terms justify it. Read the high-speed threshold, post-threshold speed, hotspot allowance and fair-use policy. “Unlimited” does not automatically mean unlimited high-speed tethering.