Typical file sizes reference table
The table lists the approximate per-item sizes used by this calculator and the resulting counts for a 256 GB device. All values are typical figures — actual file sizes depend on resolution, codec, bitrate and compression settings.
| Content type | Typical size (approx.) | Fits on 256 GB (approx.) |
|---|---|---|
| Photo, 12 MP JPEG | ~5 MB | 51,200 photos |
| Song, MP3 | ~4 MB | 64,000 songs |
| 1080p video | ~5 GB per hour | 51 hours |
| 4K video | ~20 GB per hour | 12 hours |
| Office document | ~0.5 MB | 512,000 documents |
- All per-item sizes are industry-typical approximations. RAW photos (20–50+ MB), lossless audio, high-bitrate or 60 fps video and heavily formatted documents can be several times larger.
- Video sizes depend strongly on the codec: modern HEVC/H.265 or AV1 encodes can halve the space of older H.264 at similar quality, while camera-original footage can be far larger.
- The usable-capacity estimate (~93%) reflects file-system formatting overhead and the decimal-vs-binary reporting difference; the exact figure varies by device and file system.
What does a storage capacity estimate tell you?
A storage capacity estimate divides the space available on a device by the typical size of one item — a photo, a song, an hour of video or a document — to give an approximate count of how many items fit. Because file sizes vary widely with resolution, compression and content, all such estimates are planning figures, not exact guarantees.
The typical sizes used here are stated approximations: a 12-megapixel JPEG photo is around 5 MB (smartphone photos range roughly 2–8 MB depending on scene complexity and compression), an MP3 song at common bitrates is around 4 MB, compressed 1080p video consumes roughly 5 GB per hour, 4K video roughly 20 GB per hour, and a typical office document about 0.5 MB. Actual sizes depend on the codec, bitrate and quality settings of your specific device or app.
Not all labeled capacity is available for files. Drives are marketed in decimal gigabytes (1 GB = 10⁹ bytes), operating systems often report in binary units, and the file system itself reserves space for its own structures. This calculator shows an approximate usable figure of about 93% of the labeled capacity to reflect that overhead; the exact value varies by file system and device.
How to use this storage calculator
- Enter the storage capacity in GB as printed on the drive, SSD or memory card.
- Select the type of content you plan to store — photos, songs, 1080p or 4K video, or documents.
- Read the estimated item count (or hours, for video) based on the typical size for that content type.
- Check the approximate usable capacity, which accounts for formatting and file-system overhead.
The formula behind the storage estimate
The capacity in GB is converted to megabytes (1 GB = 1,000 MB decimal), then divided by the typical size of one item in MB. The result is rounded down, because a partial file does not fit.
Worked example: a 256 GB card storing 12 MP photos. 256 GB = 256,000 MB; divided by 5 MB per photo gives 51,200 photos. For 4K video the same card holds 256,000 ÷ 20,000 = 12 full hours. The approximate usable capacity is 256 × 0.93 ≈ 238 GB.
Common mistakes
- Assuming the full labeled capacity is available for files — formatting overhead and system data reduce usable space by several percent.
- Using one 'photos per GB' figure for all cameras: a 12 MP JPEG (~5 MB) and a 45 MP RAW file (~50 MB) differ by an order of magnitude.
- Ignoring the video codec and bitrate — the same hour of 4K footage can range from ~7 GB (efficient streaming encode) to over 40 GB (high-bitrate camera original).
- Confusing decimal GB on the packaging with binary GiB reported by the operating system, which makes the device look ~7% smaller than advertised.
Frequently asked questions
How many photos fit on 256 GB?
Using a typical 5 MB size for a 12-megapixel JPEG, about 51,200 photos fit on 256 GB (256,000 MB ÷ 5 MB). Higher-resolution sensors, burst shots and RAW files reduce that number substantially — a 50 MB RAW file cuts it to roughly 5,100.
How many hours of 4K video fit on 1 TB?
At a typical consumption of about 20 GB per hour, 1 TB (1,000 GB) holds roughly 50 hours of 4K video. The real figure depends heavily on codec and bitrate: efficient HEVC encodes use less space, while high-bitrate camera originals can use double or more.
Why is the usable capacity less than the printed capacity?
Two separate effects are involved. First, the file system reserves space for its own structures when the drive is formatted. Second, drives are labeled in decimal gigabytes (10⁹ bytes) while many operating systems report binary gibibytes, making the number on screen look about 7% smaller. This calculator's ~93% usable figure is an approximation covering typical overhead.
How accurate are the typical file sizes used here?
They are stated approximations for common consumer formats: ~5 MB per 12 MP JPEG, ~4 MB per MP3 song, ~5 GB per hour of 1080p video, ~20 GB per hour of 4K video and ~0.5 MB per document. Your own files may be smaller or larger depending on resolution, bitrate, codec and compression settings, so treat the results as planning estimates.
How much storage do I need for music?
At roughly 4 MB per MP3 track, 1 GB holds about 250 songs, 64 GB about 16,000 songs and 256 GB about 64,000 songs. Lossless formats such as FLAC average roughly 5–10 times larger per track, so a lossless library needs correspondingly more space.
References
- ISO/IEC 80000-13:2008. Quantities and units — Part 13: Information science and technology — decimal vs binary storage units.
- NIST. Prefixes for binary multiples. physics.nist.gov reference on SI and IEC prefixes for data storage.