Data Storage Calculator: Bytes, Gigabytes and Terabytes
This converter moves values between bits, bytes, kilobytes, megabytes, gigabytes and terabytes. The complication is that two conventions exist — decimal powers of 1,000 and binary powers of 1,024 — and the gap between them grows with size.
Decimal versus binary units
Drive manufacturers use decimal units: 1 GB = 1,000,000,000 bytes. Operating systems such as Windows report binary units: 1 GiB = 1,073,741,824 bytes but label it GB. That is why a 1 TB drive shows as about 931 GB — the storage is not missing, the two systems are simply counting differently. The gap is about 7% at gigabyte scale and roughly 10% at terabyte scale.
Bits versus bytes
One byte is eight bits. Storage is quoted in bytes (MB, GB) while network and internet speeds are quoted in bits per second (Mbps, Gbps). A 100 Mbps connection therefore delivers about 12.5 MB per second at best. Confusing the two is the reason a 'fast' connection can feel eight times slower than expected.
Rough sizes for planning
- A 12 MP JPEG photo: 3-6 MB. A RAW file: 20-50 MB.
- An hour of 1080p video: 1.5-3 GB. An hour of 4K: 8-20 GB.
- A streamed hour of HD video: about 3 GB of data allowance.
- A typical MP3 track: 3-5 MB; a lossless track: 25-40 MB.
Key takeaways — Data Storage Calculator
- Decimal GB uses 1,000; binary GiB uses 1,024 — expect drives to appear smaller.
- Divide network megabits by 8 to get megabytes per second.
- Size backups from real file sizes and leave headroom for growth.