How many MB are in a GB?

In decimal (SI) units, 1 GB = 1000 MB = 1,000,000,000 bytes. In binary units, 1 GiB = 1024 MiB = 1,073,741,824 bytes. Drive makers use decimal GB; operating systems often report binary but label it 'GB'. This converter keeps the two families separate so you get the right answer.

What is the difference between GB and GiB?

A GB (gigabyte, decimal) is 1,000,000,000 bytes; a GiB (gibibyte, binary) is 1,073,741,824 bytes — about 7.4% larger. So 1 GB = 0.931323 GiB and 1 GiB = 1.073742 GB. The mismatch is why a '1 TB' drive shows as roughly 931 GiB in software that counts in binary.

How many bits are in a byte?

Exactly 8 bits make 1 byte. Storage and file sizes are measured in bytes (and MB, GB), while network speeds are usually in bits (megabits, Mbps) — which are one-eighth the size. So a 100 Mbps connection transfers about 12.5 MB per second, a common source of confusion.

Why does my hard drive show less space than advertised?

Because the maker advertises decimal terabytes (1 TB = 1,000,000,000,000 bytes) but your OS may display binary and call it 'GB'. 1 TB = 931.3226 GiB, so a 1 TB drive shows as ~931 'GB' in such systems. No space is missing — it's a units mismatch between decimal and binary.

Should I use decimal or binary units?

Use decimal (KB, MB, GB, TB) for storage marketing and most file-size contexts, and binary (KiB, MiB, GiB, TiB) when you need exact powers of 1024, as in memory addressing or some software. The safest practice is to state which you mean. This converter supports both and labels them clearly so results are unambiguous.

Data Storage Converter — MB, GB, TB, MiB, GiB & bits

From	Equals
1 GB	1000 MB · 0.931323 GiB
1 GiB	1024 MiB · 1.073742 GB
1 TB	1000 GB · 931.3226 GiB
1 byte	8 bits

A data storage converter moves a digital size between bytes and their multiples — and crucially between the two families that look alike but aren't. Decimal (SI) units step in powers of 1000: KB, MB, GB, TB. Binary (IEC) units step in powers of 1024: KiB, MiB, GiB, TiB. Mixing them is the classic reason a "1 TB" drive looks like only "931 GB" on your computer. This converter keeps both families separate and also handles bits (8 to a byte).

Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: IEC 80000-13 binary prefixes and SI decimal prefixes, recomputed in code.

How the conversion works

Via a base unit

result = value × bytes(from) ÷ bytes(to) (base = bytes)

Decimal (×1000)

1 KB = 10³ B · 1 MB = 10⁶ B · 1 GB = 10⁹ B · 1 TB = 10¹² B

Binary (×1024)

1 KiB = 2¹⁰ B · 1 MiB = 2²⁰ B · 1 GiB = 2³⁰ B · 1 TiB = 2⁴⁰ B · 1 B = 8 bits

Each unit equals a fixed number of bytes. To convert, express your value in bytes by multiplying by the "from" unit's bytes-per-unit, then divide by the "to" unit's. The only subtlety is choosing the right family: a megabyte (MB) is 1,000,000 bytes, while a mebibyte (MiB) is 1,048,576 bytes — about 4.9% more. The gap grows with each step, reaching ~10% at the tera level.

Worked example — 1 GB vs 1 GiB

Scenario: compare a decimal gigabyte with a binary gibibyte.

1 GB to bytes

1 × 10⁹ = 1,000,000,000 bytes = 1000 MB

1 GB to GiB

1,000,000,000 ÷ 1,073,741,824 = 0.931323 GiB

1 TB to GiB

10¹² ÷ 2³⁰ = 931.3226 GiB

A decimal 1 GB is 0.931323 GiB — about 7% smaller than a binary gibibyte. Scale that up and a 1 TB drive is 931.3226 GiB, which is exactly why a freshly formatted "1 TB" disk shows roughly "931 GB" in an operating system that counts in binary but labels it GB. Nothing is missing; it's a decimal-versus-binary units mismatch. And remember bits: 8 bits make a byte, so a 100 Mbps link moves about 12.5 MB per second.

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Frequently Asked Questions

MB in a GB?⌄

Decimal: 1 GB = 1000 MB. Binary: 1 GiB = 1024 MiB.

GB vs GiB?⌄

1 GB = 1e9 B; 1 GiB = 1,073,741,824 B (~7.4% more). 1 GB = 0.931323 GiB.

Bits in a byte?⌄

8. Speeds use bits (Mbps); storage uses bytes (MB). 100 Mbps ≈ 12.5 MB/s.

Why does my drive show less?⌄

1 TB (decimal) = 931.3226 GiB. The OS counts in binary but labels it GB.

Decimal or binary?⌄

Decimal for storage marketing/files; binary for exact powers of 1024. State which.

Data Storage Converter

Data storage conversion — Quick answer