These are planning assumptions used by the Corelinx travel data calculator, not measured averages from a traveler survey or an app test. We add a 20% buffer and use 1 GB = 1,000 MB for these calculations. App settings, video quality, uploads and background activity can substantially change the result.
What actually uses up travel data?
Your data runs out because of what you do, not how long your phone is on. An hour of maps costs far less than ten minutes of video. These are the illustrative inputs behind the calculations below:
| Activity | Planning assumption | Notes |
|---|---|---|
| Messaging and notifications | ~60 MB per day | More if you send lots of photos and videos |
| Maps and navigation | ~50 MB per hour | Lower with offline maps |
| Browsing | ~60 MB per hour | Image-heavy pages cost more |
| Music streaming | ~80 MB per hour | Download playlists before you fly |
| Social media (Instagram, TikTok) | ~300 MB per hour | Autoplay video is the main culprit |
| Video calls | ~400 MB per hour | Varies by app and network quality |
| Video streaming (YouTube, Netflix) | ~1.5 GB per hour | Much lower or higher depending on quality |
For an official reference point, Netflix's help center lists up to about 0.3 GB per hour on low quality, 0.7 GB on medium and up to 3 GB per hour in HD (Netflix Help Center, checked 19 October 2026). One habit, watching video on the go, can turn a 5 GB week into a 20 GB-plus week.
How much data do I need for 3, 7 and 14 days?
We use three usage profiles. All figures include the 20% buffer.
- Light: messaging, about 1 hour of maps, 1 hour of browsing and 30 minutes of social media a day, or about 0.4 GB/day.
- Moderate: messaging, about 2 hours of maps, 1.5 hours of social media, a 30-minute video call, plus an hour each of browsing and music, or about 1.1 GB/day.
- Heavy: messaging, 2 hours of maps, 2 hours of social media, 1 hour of video calls, 1 hour of video streaming, and 1 hour each of browsing and music, or about 3.4 GB/day.
| Profile | 3 days | 7 days | 14 days |
|---|---|---|---|
| Light (~0.4 GB/day) | ~1.2 GB → 3 GB plan | ~2.7 GB → 3–5 GB plan | ~5.4 GB → 10 GB plan |
| Moderate (~1.1 GB/day) | ~3.4 GB → 5 GB plan | ~8 GB → 10 GB plan | ~16 GB → at least 20 GB |
| Heavy (~3.4 GB/day) | ~10.1 GB → at least 15 GB | ~23.5 GB → at least 25 GB | ~47 GB → at least 50 GB |
For a two-week trip, choose a plan valid for 15 days or longer, since travel plans usually come in fixed lengths such as 3, 5, 7, 10, 15 or 30 days. Your habits look different? Enter your own hours in the data calculator and it rounds up to the nearest plan size.
Worked example: one week in Japan
Say you spend a week between Tokyo and Osaka. During the day you use maps and transit apps for about 2 hours and social media for about an hour. In the evening you video call home for 20 minutes, but on hotel Wi-Fi.
- Maps: 2 hours × 50 MB = 100 MB
- Social media: 1 hour × 300 MB = 300 MB
- Messaging and notifications: 60 MB
- Video call on hotel Wi-Fi: 0 MB of your plan
- Total: ~460 MB/day × 7 days ≈ 3.2 GB, plus 20% ≈ 3.9 GB
Under those assumptions, a 5 GB plan gives room above the 3.9 GB estimate. Move that video call to mobile data and add some video on the train, and you are looking at 10 GB or more. Download your map areas before the trip too. Our guide to offline maps and transit backups in Japan explains what offline maps can and cannot replace.
Fixed data or daily unlimited: which should you pick?
- Fixed data (for example 5 GB for 7 days): use it whenever you like during the validity period. Good for light to moderate users, because quiet days leave more data for busy ones.
- Daily unlimited (for example "Unlimited 1GB/day"): some plans have a full-speed daily allowance, followed by reduced speed under that plan’s terms. Check the actual allowance and reset timing; it may be too small for heavy use.
Compare both the total trip allowance and the amount you need on your busiest day. An unlimited label does not promise unlimited full-speed data. A 1 GB/day full-speed cap is below this guide’s heavy-use estimate of 3.36 GB/day. Check the specific plan’s full-speed allowance, reduced speed, reset timing, validity and hotspot policy before buying; there is no universal 20 GB value threshold.
Use the live Japan plan page to compare current prices for the allowance and validity you need. Check the full plan details rather than comparing unlimited labels alone.
Check whether the exact plan permits hotspot use and whether a separate limit applies.
Sharing a hotspot with a laptop or family phones
A hotspot means several devices draw from one plan, and laptops use far more than phones because of system updates, cloud sync and video meetings. If you plan to share, estimate each person's needs and add them together. The Corelinx calculator has a hotspot option for exactly this. Pause automatic sync and updates on the laptop before connecting.
How to make your travel data last
- Download offline maps before you leave. Google Maps lets you save areas for offline use. Routes must stay inside the downloaded area, though, and transit, cycling and walking directions are not available offline (Google Maps Help, checked 19 October 2026).
- Turn on Low Data Mode on iPhone. Apple says it restricts background network use. On Dual SIM iPhones the setting is per line, so enable it on your travel eSIM (Apple Support). Android phones have a Data Saver option under data usage settings, though menu names vary by brand.
- Use less data for WhatsApp calls. WhatsApp has a "Use less data for calls" option under Settings > Storage and data (WhatsApp Help Center).
- Lower video quality. Netflix estimates about 6 hours of viewing per GB on the mobile Save Data setting, against about 4 hours per GB on Automatic (Netflix Help Center).
- Disable autoplay in Instagram, TikTok and YouTube, and stop photo backups over mobile data.
- Check usage on day one. On iPhone, go to Settings > Cellular to see usage by app, and reset the statistics before you travel (iPhone User Guide). If day one runs heavy, you still have time to adjust.
Running a travel eSIM next to your home SIM? Make sure the travel line is the one handling mobile data. Our Dual SIM setup guide walks through it so your home plan does not quietly pick up roaming charges.
Frequently asked questions
Is 1 GB a day enough for travel?
It depends on your habits. The moderate example above needs about 0.95 GB/day before the buffer, or 1.14 GB/day with it. A strict 1 GB daily allowance leaves less room for uploads or a longer call. Use your phone’s measured app usage to refine the estimate.
How much data do I need for a week abroad?
Under these assumptions, light use totals about 2.7 GB for seven days and moderate use about 8 GB. Round up to a suitable bundle. Heavy use reaches about 23.5 GB; compare a larger fixed bundle with a daily plan whose full-speed allowance actually matches your needs.
Is fixed data or unlimited better value?
Compare the actual price, validity, full-speed allowance and any reduced-speed policy for your destination. Fixed data lets you spread usage unevenly across days. Daily plans can suit steady use, but a low daily cap can be restrictive even when the label says unlimited.
How much data does a video call use?
Plan on roughly 400 MB per hour. A 20-minute call every day for a week comes to about 1 GB, so use hotel Wi-Fi where you can.
Do offline maps really save data?
Yes, for viewing maps and driving navigation within the downloaded area. Google Maps does not offer transit or walking directions offline, so keep some data for train and bus routes.
What if I run out of data mid-trip?
Check whether your current plan supports a top-up. Otherwise, you may need to buy and install another compatible plan using a working internet connection. Do not delete the existing profile before checking the installation instructions; a QR code may not be reusable.
Stay connected
Got a rough number? Fine-tune it with the data calculator, then pick a plan size for your destination. Japan, for example, has fixed-data and daily unlimited plans in several lengths on the Japan eSIM plans page, or you can browse every destination in the Corelinx eSIM plan list.
Cover image: AI-generated editorial illustration, not documentation of a particular venue or an app test.
