A megabyte is 1,048,576 bytes. A gigabyte is 1,024 megabytes. A terabyte is 1,024 gigabytes. These three units are the scale most people need to understand to make sense of phone, camera, and computer storage in 2026.
The base unit: bytes and kilobytes
Everything stored on a device, every photo, every video, every app, starts at the byte level. A single byte is one character of data. A kilobyte is 1,024 bytes. These units are too small to be useful for thinking about photos or video, which is why everything starts at the megabyte level in practice.
Megabytes (MB): the photo unit
One megabyte is exactly 1,048,576 bytes, calculated as 1,024 squared, according to Build5Nines. In practical terms, a megabyte is roughly the size of a single smartphone photo.
The average file size for modern smartphone photos ranges from 3 MB to 9 MB for standard JPEG files, according to industry data. That means a single photo takes up somewhere between 3 and 9 megabytes of storage on a phone.
Gigabytes (GB): the daily-use unit
One gigabyte equals 1,024 megabytes. This is the unit most people interact with day to day, because it is the scale at which photos, video, and apps start to add up.
A 1 GB storage capacity holds approximately 250 to 300 photos based on an average 12-megapixel photo size of 3 to 4 MB, according to AllUnitConverter. But video changes that math dramatically. One minute of 4K video footage can exceed 1 GB in size, meaning 1 GB holds less than one minute of high-bitrate 4K video, according to CNET.
Terabytes (TB): the library unit
One terabyte equals 1,024 gigabytes. This is the scale at which an entire photo and video library lives.
A 1 TB drive stores approximately 200,000 to 500,000 photos, depending on whether they are smartphone images at 3 to 5 MB each or larger DSLR RAW files, according to MobiSystems. For video, a 1 TB storage capacity fits approximately 65 to 85 hours of 4K video.
Why this matters for phone storage in 2026
Base storage tiers have been climbing, but not fast enough to outpace how much media people generate. The iPhone 17 series in 2026 raised the base storage to 256 GB, according to CNET, a meaningful jump from the 128 GB that had been the entry-level standard for years. But even at 256 GB, that is only about one-quarter of a terabyte.
For someone taking 20 photos a day at an average of 4 MB each, that is roughly 80 MB per day, or about 29 GB per year in photos alone, before any video is factored in. Add regular 4K video recording, and a 256 GB phone can fill up within months rather than years.
The key conversions to remember
- 1 MB = 1,048,576 bytes (roughly one photo)
- 1 GB = 1,024 MB (roughly 250 to 300 photos, or less than one minute of 4K video)
- 1 TB = 1,024 GB (roughly 200,000 to 500,000 photos, or 65 to 85 hours of 4K video)
Understanding these three units, and how quickly video scales past photos, is the foundation for making smart decisions about how much storage you actually need and where your space is actually going.