How many bits are in a terabyte?

One SI terabyte (TB) equals 8,000,000,000,000 bits (8 × 10^12). One IEC tebibyte (TiB) equals 8,796,093,022,208 bits (8 × 2^40). The ~9.95% gap is why storage drives appear smaller in your OS than on the packaging.

What is the difference between TB and TiB?

TB (terabyte) is the SI decimal unit: 1 TB = 1,000,000,000,000 bytes. TiB (tebibyte) is the IEC binary unit: 1 TiB = 1,099,511,627,776 bytes. Storage makers and current macOS use decimal units; Windows commonly reports binary quantities while labeling them GB or TB.

Why does my 1 TB drive show as about 931 GB in Windows?

Drive manufacturers count in SI (1 TB = 10^12 bytes). Windows divides that byte count by 2^30 but commonly labels the result GB: 10^12 ÷ 2^30 ≈ 931.323 GiB. Expressed in tebibytes, the same capacity is about 0.909 TiB.

How do I convert Tbps (terabits per second) to TB/s?

Divide the terabit value by 8. For example, a 10 Tbps backbone link can transfer 1.25 TB/s in SI terms, or about 1.136 TiB/s in binary terms. This tool handles the bit-to-byte conversion step automatically.

Can I enter values larger than terabits?

The "Convert from" dropdown includes petabits, so you can scale large inputs before computing terabytes. JavaScript floating-point handles values accurately across the full range needed for practical data-size conversions.

Bits to Terabytes Converter

Enter a bit count and instantly see the equivalent in terabytes (SI decimal) and tebibytes (IEC binary).

Input Value

Amount

Convert from

Quick Reference

1 TB (SI) = 8,000,000,000,000 bits
1 TiB (Binary) = 8,796,093,022,208 bits
1 Tbps = 0.125 TB/s

Results

Enter a value and click Convert to see results.

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Summary

This converter takes any bit count and outputs the equivalent in terabytes under both common standards. The SI decimal terabyte (TB) equals exactly 1,000,000,000,000 bytes (10^12) — the value used on hard drive and SSD packaging. The IEC binary tebibyte (TiB) equals 1,099,511,627,776 bytes (2^40). One decimal TB is about 0.909 TiB, or 931.323 GiB; Windows commonly displays that binary quantity as roughly 931 GB, while current macOS uses decimal storage units.

How it works

Enter any number of bits in the input field.
Optionally change the "Convert from" unit if your value is already in kilobits, megabits, gigabits, or terabits.
Click Convert (or press Enter) to calculate.
The converter divides by 8 to get bytes, then divides by 10^12 for TB (SI) and 2^40 for TiB (binary).
Copy any result with the copy icon next to it.

Use cases

Check how many terabytes a large dataset or backup archive occupies when given only a bit count.
Convert network throughput from terabits per second to terabytes per second.
Translate storage specs between marketing labels (SI) and OS reports (binary).
Calculate video archive or cloud storage sizes from raw bitrate and duration data.
Understand why a "1 TB" drive shows as about 931 GB in Windows.
Convert backbone or data-center bandwidth expressed in Tbps to practical TB/s values.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu