In detail
20 GB fits people who scroll social media daily, stream music on the commute and watch the occasional video on mobile data. It covers about 6–7 hours of HD video or around 28 hours in SD per month — enough for a show a week if you lower the quality on mobile.
What uses data is almost always video. In HD, 20 GB lasts about 6.7 hours; in SD about 28.6 hours; in 4K only about 2.9 hours. Everything else is light by comparison: 20 GB is about 133 hours of music streaming, and messaging, email and maps use only a few hundred megabytes a month.
On a two-week trip, 20 GB leaves room for maps, messaging, social media and a few hours of video, which is why it's one of the most popular travel eSIM sizes.
Spread over a month, 20 GB is about 0.7 GB per day; over two weeks it is about 1.4 GB per day. The calculator above shows how many days 20 GB lasts with your own mix of activities, and whether it's enough for a week, two weeks or a whole month.
To make 20 GB last longer, set video apps to data saver on mobile networks, download shows and playlists over Wi-Fi, turn off autoplay on social media and check which apps use background data in your phone's settings.