Data volume to terabytes converter
Storage sizes come in two systems that are easy to mix up: decimal units used by drive makers and cloud providers, and binary units used by Windows and many servers. Enter a size in any unit to see it in all of them at once, or switch to record counts and turn a number of emails, documents, photos, recordings or database rows into terabytes. The converter also shows how many drives the data needs and what it costs to keep in the cloud.
In every unit
| Decimal unit | Value | Binary unit | Value |
|---|
How the conversion works
Everything is converted to bytes first, then from bytes into each unit. Decimal units step up by 1,000; binary units step up by 1,024.
Turn the input into bytes
A size is multiplied by its unit. Record counts are multiplied by the average size of each record type and added up.
bytes = amount × unit size or Σ count × average size
Convert to decimal units
TB = bytes ÷ 1,0004
Convert to binary units
This is what Windows Explorer shows, even though it labels it TB.
TiB = bytes ÷ 1,0244
Work out drives and cost
Drives needed leaves 10 percent free space on each drive. Cloud cost is gigabytes times the monthly price.
Questions about data sizes and terabytes
How many gigabytes are in a terabyte?
A terabyte (TB) is 1,000 gigabytes in the decimal system used by drive makers and cloud providers. A tebibyte (TiB) is 1,024 gibibytes, about 10 percent more. Both are often just called "terabytes", which is why the converter shows them side by side.
Why does Windows show my 2 TB drive as 1.81 TB?
Windows counts in binary units (1 KB = 1,024 bytes) but labels them TB. The drive maker counts in decimal (1 KB = 1,000 bytes). The bytes are the same; only the unit differs. 2 TB in decimal is 1.82 TiB, which Windows shows as 1.81 or 1.82 "TB".
How many emails fit in a terabyte?
At an average of 75 KB per email including attachments, about 13 million. Plain text emails with no attachments are closer to 10 KB, so a terabyte would hold around 100 million of them.
How do I estimate the size of my company data?
Switch to "From record counts" and enter what you know: how many emails, documents, photos, recordings and database rows you have. The average sizes are typical figures; replace them with your own if you know them, for example from the size of one exported folder divided by its file count.
What is a petabyte?
A petabyte (PB) is 1,000 terabytes, or a million gigabytes. Only large enterprises, video platforms and research projects store data at that scale. Most small and mid-size companies hold somewhere between a few hundred gigabytes and a few dozen terabytes.