Storage labels commonly use decimal units, while some operating systems and tools display binary units. This calculator shows both and estimates file capacity using the formula you can inspect. Real usable space is lower after formatting, system files, recovery partitions and application data.
Convert capacity and estimate file count
All fields are required. Results are estimates, not promises of usable formatted space.
Formula and assumptions
Decimal storage uses powers of 1000: 1 GB equals 1,000,000,000 bytes and 1 TB equals 1,000 GB. Binary units use powers of 1024: 1 GiB equals 1,073,741,824 bytes and 1 TiB equals 1,024 GiB.
Estimated file count equals total bytes divided by average file bytes, rounded down. The estimate does not subtract file-system overhead, reserved space, operating-system files or application data.
Use the estimate responsibly
- Photos and videos vary widely by format, resolution, compression and duration.
- Keep free working space for updates, temporary files and application caches.
- Capacity planning is not a backup plan; important data needs separate verified copies.
- Recorder and CCTV storage sizing also depends on bitrate, frame rate, retention and recording mode.
Sources and further reading
Technical statements were reviewed against these references. External pages may change after our review date.
- Definitions of the SI units: The binary prefixes — National Institute of Standards and Technology
- The International System of Units: SI prefixes — Bureau International des Poids et Mesures