How to Use This Tool

Data size converter

Type a value into any field and the converter calculates the rest. It covers bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes. This page uses the standard decimal (SI) definitions where 1 KB = 1,000 bytes, with binary (IEC) equivalents noted where they matter.

Common data size conversions

Data size conversion formulas

Megabytes to gigabytes

GB = MB / 1,000

Example: 4,500 MB / 1,000 = 4.5 GB.

Gigabytes to megabytes

MB = GB x 1,000

Example: 2.5 GB x 1,000 = 2,500 MB.

Gigabytes to terabytes

TB = GB / 1,000

Example: 500 GB / 1,000 = 0.5 TB.

Megabits to megabytes

MB = Mb / 8

Example: A 100 Mbps internet connection transfers 100 / 8 = 12.5 MB per second under ideal conditions.

Terabytes to gigabytes

GB = TB x 1,000

Example: A 2 TB hard drive holds 2,000 GB in decimal terms. The operating system may report it as about 1,862 GiB because it uses binary counting.

When you need data size conversions

Buying storage

Hard drives and SSDs are marketed in decimal gigabytes or terabytes (1 TB = 1,000,000,000,000 bytes). Operating systems like Windows report sizes in binary gibibytes (1 GiB = 1,073,741,824 bytes). A drive labeled 1 TB shows up as about 931 GiB in Windows. This is not missing space. It is the same number of bytes described two different ways.

Internet speed and downloads

Internet speeds are advertised in megabits per second (Mbps), but file sizes are in megabytes (MB). Divide the speed by 8 to get the download rate in megabytes per second. A 200 Mbps connection downloads at roughly 25 MB/s. A 4 GB file on that connection takes about 160 seconds, or just under 3 minutes, assuming no overhead.

Cloud storage and backups

Cloud services sell storage in GB or TB. Knowing how much your files take helps you pick a plan. A typical smartphone photo is 3 to 5 MB. A thousand photos take 3 to 5 GB. A minute of 4K video is roughly 350 to 400 MB, so an hour of footage needs about 22 GB.

Email and file sharing

Email attachments are usually limited to 25 MB. File sharing services cap uploads at various sizes. Knowing the difference between KB, MB, and GB helps you figure out whether a file will fit. A 10-page Word document is typically 50 to 500 KB. A high-resolution photo is 3 to 10 MB. A short video can easily be 50 to 200 MB.

Common file sizes

Tips for accurate conversions

• Bits and bytes are different. A byte is 8 bits. Internet speeds use bits (Mbps), while file sizes use bytes (MB). Always divide by 8 when converting from bits to bytes.
• Decimal (SI) and binary (IEC) units differ by about 7% at the gigabyte level and about 10% at the terabyte level. A “500 GB” drive holds 500,000,000,000 bytes, which is about 465.66 GiB.
• Storage manufacturers use decimal units. Operating systems historically use binary units, though macOS switched to decimal in 2009. Windows still shows binary values with decimal labels, which is why a “1 TB” drive shows as “931 GB” in Windows Explorer.
• When estimating download times, account for protocol overhead. Real-world download speeds are typically 80 to 90% of the advertised connection speed.

Decimal vs. binary units

The confusion between KB and KiB goes back to the early days of computing. Computer memory naturally works in powers of 2, so 1,024 bytes became informally known as a “kilobyte.” But in every other field of science, “kilo” means 1,000. The IEC introduced new prefixes in 1998 to fix this: kibibyte (KiB, 1,024 bytes), mebibyte (MiB, 1,048,576 bytes), and gibibyte (GiB, 1,073,741,824 bytes).

In practice, storage manufacturers and most modern software use decimal (1 KB = 1,000 bytes). RAM is still measured in binary (a “16 GB” RAM stick has 16 x 1,073,741,824 bytes). The difference grows with scale: at the kilobyte level it is 2.4%, at the gigabyte level 7.4%, and at the terabyte level 10%.

Frequently asked questions

How many MB in a GB?

1 GB = 1,000 MB (decimal) or 1,024 MiB (binary).

How many GB in a TB?

1 TB = 1,000 GB (decimal) or 1,024 GiB (binary).

Why does my hard drive show less space than advertised?

The drive maker uses decimal counting (1 TB = 1,000,000,000,000 bytes). Your operating system may display the same bytes using binary counting, where 1 GiB = 1,073,741,824 bytes. The result is a lower number for the same physical capacity.

What is the difference between Mbps and MBps?

Mbps is megabits per second, used for internet speeds. MBps is megabytes per second, used for file transfer rates. 1 MBps = 8 Mbps.

How long does it take to download 1 GB?

At 100 Mbps, about 80 seconds. At 50 Mbps, about 160 seconds. At 10 Mbps, about 800 seconds (over 13 minutes). These assume the full connection speed is available.

How many photos can 1 GB hold?

About 200 to 330 smartphone photos at 3 to 5 MB each.

How many songs can 1 GB hold?

About 200 to 330 MP3 files at 3 to 5 MB each (roughly 4 minutes per song at 128-256 kbps).

What comes after terabyte?

Petabyte (PB, 1,000 TB), exabyte (EB, 1,000 PB), zettabyte (ZB, 1,000 EB), yottabyte (YB, 1,000 ZB). Global internet traffic was estimated at several zettabytes per year as of the mid-2020s.

Related conversion tools

• Percentage Calculator
• Fraction to Decimal Converter
• Time Converter
• Weight Converter

Measurement guides

• How Big Is X Inches? A Visual Size Guide From 1 to 16 Inches
• Inches Explained: Conversion Chart, Tools, and Real-World Examples

Formula & Explanation

This converter uses the binary convention (1024-base). If you need decimal (1000-base) conversions, divide the binary result by 1.024 at each step.