Short answer: it depends on video quality. As a guide, a call running at 0.5 to 1.5 megabits per second each way uses roughly 4 to 11 MB a minute in each direction, or about 0.45 to 1.35 GB an hour once you count both sides of the call.
The simple maths behind the number
Video quality is measured in megabits per second (Mbps), while your data plan counts megabytes (MB). There are 8 bits in a byte, so 1 Mbps for one minute is 60 ÷ 8 = 7.5 MB.
That gives you a rule of thumb you can use for any call: multiply the bitrate by 7.5 to get megabytes per minute, then by 60 again for an hour.
| Bitrate | Per minute (one way) | Per hour (one way) | Per hour (both ways) |
|---|---|---|---|
| 0.5 Mbps | 3.75 MB | 225 MB | 450 MB |
| 1 Mbps | 7.5 MB | 450 MB | 900 MB |
| 1.5 Mbps | 11.25 MB | 675 MB | 1.35 GB |
| 2.5 Mbps | 18.75 MB | 1.125 GB | 2.25 GB |
Use the rows as a guide rather than a promise: a real call moves around as the connection changes, and a sharp HD call can go higher still.
Why a video call counts twice
On a call you send your own video and receive the other person’s at the same time. Mobile plans count upload and download alike, so a call that streams 1 Mbps each way costs you about 15 MB a minute, not 7.5.
That is also why a video call can use more data than watching a video of the same quality: ordinary streaming sends almost all of its data in one direction.
Video, voice and text are nowhere near each other
Voice needs a small fraction of what video does. Speech is usually carried at tens of kilobits per second, which comes to well under 1 MB a minute each way. Plain text uses very little data compared with either.
On ChatMatch you choose video, voice or text before you are matched, so the mode you pick is the biggest data decision you make. Voice asks for your microphone only, and text asks for neither camera nor microphone.
What pushes the number up or down
- Connection quality. Video calls adapt: on a weak connection the picture gets softer and uses less data, and on a strong one it sharpens and uses more.
- How long you stay. Data grows minute by minute while a call is live, so an idle call left running still counts.
- Other apps. Background updates, cloud photo backups and streaming in another tab all share the same connection and the same allowance.
- Screen size isn’t a reliable guide. Data use depends on the video actually being sent and received: its resolution, frame rate and how it adapts to your connection.
Keeping a video chat light on mobile data
- Use Wi-Fi for video whenever you can, and keep mobile data for voice or text.
- If you are about to switch from Wi-Fi to mobile data, finish or end the video call first rather than letting it carry on.
- Close anything else that is streaming or uploading while you are on a call.
- Set a data warning in your phone settings so a long call doesn’t surprise you at the end of the month.
Check your own number in five minutes
The figures above are typical ranges, not a promise, because every call adapts to its connection. To see your real number, note your browser’s data use, make a five-minute video call on mobile data, then check again.
On iPhone, open Settings, then Mobile Data (called Cellular in the US), and scroll down to Safari. On Android, open Settings and search for “data usage”, then find your browser in the list. Multiply the difference by 12 for a rough hourly estimate under similar conditions.
On mobile data? Start in voice or text.
Pick your mode before you match. Voice uses the microphone only; text needs neither camera nor mic.