KB, MB and GB Converter – File Size Calculator

Convert any amount between MB and GB, MB and KB, or KB and MB. Check file sizes, storage capacity, and data plans with decimal and binary units.

From

Common conversions

Decimal vs Binary Units

Decimal (SI Units)

Used by storage manufacturers. Based on powers of 1000.

1 KB = 1,000 bytes
1 MB = 1,000 KB = 1,000,000 bytes
1 GB = 1,000 MB = 1,000,000,000 bytes
1 TB = 1,000 GB

IEC

Binary (IEC Units)

Used by operating systems. Based on powers of 1024.

1 KiB = 1,024 bytes
1 MiB = 1,024 KiB = 1,048,576 bytes
1 GiB = 1,024 MiB = 1,073,741,824 bytes
1 TiB = 1,024 GiB

Why does my drive show less space? A "1 TB" drive (1,000,000,000,000 bytes) shows as ~931 GiB in your OS because it uses binary calculation.

Common File Sizes

Text document (1 page)~10 KB

MP3 song (4 min)~4 MB

JPEG photo (12 MP)~3-5 MB

HD Video (1 hour)~3-4 GB

4K Video (1 hour)~20-30 GB

Blu-ray movie~25-50 GB

Convert any numeric amount between MB, GB, KB, bytes, and their IEC binary counterparts. Get answers for questions such as 1000 MB to GB, 1 MB to KB, or 20 MB to KB.

What is an MB, GB and KB converter?

This calculator converts any entered number between bit, byte, KB, MB, GB, TB, PB and the IEC units KiB, MiB, GiB, TiB and PiB. It is useful when checking a file size, storage capacity, or a data allowance.

When to use it

MB to KB or GB

Convert an entered amount such as 20 MB to KB or 21854 MB to GB.

KB to MB calculations

Check questions such as how many MB are in 1000 KB using the selected unit convention.

Decimal and binary sizes

Compare storage and operating-system units, including MB versus MiB and GB versus GiB.

How conversion works

Decimal units use powers of 1000: 1 MB = 1,000 KB and 1 GB = 1,000 MB. IEC binary units use powers of 1024: 1 MiB = 1,024 KiB and 1 GiB = 1,024 MiB. The result is calculated from the entered number and selected units.

Data Comparison Table

Unit	Decimal (Base 10)	Binary (Base 2)
Kilobyte	1,000 Bytes	1,024 Bytes (KiB)
Megabyte	1,000,000 Bytes	1,048,576 Bytes (MiB)
Gigabyte	10^9 Bytes	2^30 Bytes (GiB)

Developer Friendly

Choose from seven decimal units (bit, byte, KB, MB, GB, TB, PB) or five IEC binary units (KiB, MiB, GiB, TiB, PiB). Enter any numeric value; the result is formatted for your locale with up to six fractional digits.

Frequently Asked Questions

How many MB are in 1 GB?

In decimal units, 1 GB equals 1000 MB. In binary units, 1 GiB equals 1024 MiB. Choose the explicitly labeled unit in the converter to match your file or storage measurement.

How many GB is 1000 MB?

With the decimal units used by this calculator, 1000 MB equals 1 GB.

How many KB is 1 MB?

With decimal units, 1 MB equals 1000 KB.

How many MB is 1 GB?

With decimal units, 1 GB equals 1000 MB.

What is the difference between MB and MiB?

MB is decimal and equals 1,000,000 bytes; MiB is binary and equals 1,048,576 bytes. The same distinction applies to GB and GiB.