- Rough data use per activity, from a Japanese government guide
- Turning 3GB, 10GB and 30GB into hours of video
- Checking your own usage on iPhone and Android
The short answer
Whether 3GB, 10GB or 30GB is enough comes down mostly to how much video you watch away from Wi-Fi. News and email go a long way even on 1GB, but video grows with every hour and every step up in quality. Rather than reasoning from plan sizes, check last month's usage on your own phone. This article is written for mobile plans in Japan, where plans are commonly sold in gigabyte tiers like these.
What 1GB covers, roughly
The mobile phone portal of Japan's Ministry of Internal Affairs and Communications (MIC) publishes a rough guide to data use, which MIC compiled with reference to carriers' websites and other sources. Treat it as a rough guide only. Real use varies by site, app and settings.
| Activity | Per use, roughly | Per 1GB, roughly |
|---|---|---|
| Reading a news site | About 0.3MB per page | About 3,300 pages |
| Sending or receiving email | About 0.5MB per message | About 2,000 messages |
| Using a map app | About 1MB per 10 minutes | About 1,000 ten-minute sessions |
| Watching standard-quality video | About 300 to 500MB per hour | 2 to 3 hours |
Video stands out by an order of magnitude.
Actual use varies a lot with quality, settings and apps.
These are monthly totals. Your own usage is in your phone settings or your carrier's app.
3GB, 10GB and 30GB as hours of video
Multiplying the guide's figure of 2 to 3 hours of standard-quality video per 1GB gives the table below. It is arithmetic on a rough guide, not a promise of what you will actually get.
| Plan size | Standard-quality video, roughly | Per day over 30 days |
|---|---|---|
| 3GB | 6 to 9 hours | 12 to 18 minutes |
| 10GB | 20 to 30 hours | 40 minutes to 1 hour |
| 30GB | 60 to 90 hours | 2 to 3 hours |
Higher quality means more data. YouTube Help also notes that higher quality uses more data. For example, watching 30 minutes of video on each leg of a daily commute adds up to about 30 hours a month, which by this arithmetic reaches the top of the 10GB range of 20 to 30 hours even at standard quality.
Checking your own usage
On iPhone, open the Settings app, go to the cellular section, scroll to the app list and tap Show All to see each app's usage. Reset Statistics at the bottom of the screen sets the count back to zero, so the period covered depends on when it was last reset. With dual SIM, you see the usage for the line you select.
On Google Pixel, open Settings, then Network and internet, then Internet, and tap the settings icon next to your carrier to see the total. App data usage shows the breakdown. On other Android phones, screen names and locations vary by manufacturer. Menu names in the English interface may also differ from the Japanese help pages cited here.
Apple's help says to contact your carrier for the most accurate usage in the current period, and Google's help notes that some carriers measure usage differently. Check what you have left in your carrier's account page or app.
Cutting back, and where to check
- Connect to Wi-Fi at home and at work
- In the YouTube app's video quality settings, set a lower quality for mobile networks
- Use Low Data Mode on iPhone, or data warnings and limits on Android
For the speed you get after using up your allowance, and any extra charges, check your carrier's own information.
Checklist
- Did you check last month's mobile data usage?
- Did you see which apps use the most?
- Did you work out your video time away from Wi-Fi per day?
- Did you check your remaining data in your carrier's account page or app?
One thing to check today
Check last month's mobile data usage in your phone's settings or your carrier's app.