Data Storage Converter

About this Data Storage Converter

The Data Storage Converter uses 1,024-based steps between byte, kilobyte, megabyte, gigabyte and terabyte labels. Storage vendors and operating systems sometimes use different decimal or binary conventions, so the tool states its 1,024-based assumption clearly.

Digital storage units are technically based on powers of 1024 rather than clean powers of 1000, which is why a 1 TB hard drive often shows less usable space in an operating system that reports storage using the 1024-based binary convention rather than the manufacturer's 1000-based decimal labeling.

For related tasks, try Data Transfer Rate Converter, Frequency Converter or Unix Timestamp Converter.

How to use it

1. Enter the storage amount.
2. Choose the source unit.
3. Choose the target unit and convert.

Practical example

Under the 1,024-based convention used here, 1 GB equals 1,024 MB and 1 MB equals 1,024 KB.

1 gigabyte (1024-based) equals 1,024 megabytes, which equals 1,048,576 kilobytes, so a 4 GB file is actually 4,194,304 KB, a number that quickly becomes unwieldy to calculate by hand for larger file sizes.

Things to double-check

This discrepancy between 1000-based (decimal, used by drive manufacturers) and 1024-based (binary, often used by operating systems) definitions explains why a drive advertised as 500 GB might show closer to 465 GB in Windows or macOS; both numbers are technically correct under their respective definitions.

Binary units on this converter

This converter uses 1,024 steps: 1 KB is 1,024 bytes, 1 MB is 1,024 KB, 1 GB is 1,024 MB and 1 TB is 1,024 GB. So 1 GB is 1,073,741,824 bytes. Storage makers usually advertise capacity in decimal units, where 1 GB is exactly one billion bytes. That is why a drive sold as 1 TB shows up as about 931 GB in an operating system that uses binary units. Neither is a mistake; they are two different conventions for the same prefix.

Estimating what fits

Conversions help you estimate how many files fit. A photo of 4 MB means about 256 photos per GB, since 1,024 divided by 4 is 256. A 700 MB video is about 0.68 GB, and a 2 GB movie uses a quarter of an 8 GB phone's storage if the phone has no other data. Remember that the operating system, apps and cached files use part of the advertised space, so the usable amount is less than the label.

Bits versus bytes

A byte is 8 bits. File sizes are given in bytes and network speeds in bits per second, which leads to confusion: a 100 megabit connection moves about 12.5 megabytes each second. A capital B means bytes and a lower-case b means bits, so MB and Mb are very different. If you are converting between storage and speed, use the Data Transfer Rate Converter alongside this tool.

Planning storage and backups

When planning backups, convert everything to the same unit and add a safety margin. If you have 350 GB of files that grow 10 percent a year, you need about 385 GB next year and 424 GB the year after. Compressed files such as photos, music and video will not shrink much when archived, while text and documents may shrink a lot. Keep at least one backup in a different location, and check the drive's real usable capacity before you buy.

Typical file sizes

A feel for typical sizes helps you plan. A song as an MP3 is about 3 to 5 MB, a phone photo about 3 to 8 MB and a minute of 1080p video about 100 to 150 MB. A high definition film is often 2 to 5 GB and a 4K film can be 15 to 30 GB. A 64 GB phone therefore holds roughly 10,000 photos or a dozen 4K films, before the system and apps take their share. Use the converter to translate between MB, GB and TB when you compare plans, backups and memory cards.

Worked example: a photo library

Suppose you have 1,500 photos of about 4.5 megabytes each. That is 6,750 megabytes, or about 6.59 gigabytes when dividing by 1,024. A backup drive of 500 gigabytes would hold around 110,000 such photos. If your library grows by 15 percent a year, a 250 gigabyte collection will be about 288 gigabytes next year and 331 the year after. Doing this kind of sum helps you decide how much storage to buy and when you will need more. Remember to count videos, which take much more space than photos, and to keep room for a second copy.

Decimal and binary units

Two systems describe storage. Manufacturers use decimal units, where a gigabyte is one billion bytes. Operating systems often use binary units, where a gigabyte is 1,073,741,824 bytes. The international standard names the binary units kibibyte, mebibyte and gibibyte to tell them apart, but most people still say gigabyte for both. A drive sold as 500 gigabytes therefore shows as about 465.7 in a system that uses binary units. This converter uses steps of 1,024, so results match what many computers report. Knowing the difference stops you from thinking that a drive is missing space.

Choosing a storage or cloud plan

Cloud plans are priced by capacity, so compare the cost per gigabyte. A plan of 100 gigabytes at 2 a month costs 0.02 per gigabyte, while a plan of 2 terabytes at 10 costs about 0.005. Free plans of around 15 gigabytes fill quickly with photos and email. Before you pay for more, delete duplicates, remove large files you no longer need and use compression for archives. For important files, keep at least one copy off the device and another in a different place, and check that restoring a backup actually works.

Typical sizes of media

Knowing typical sizes helps with planning. A music file at 128 kilobits per second uses about 0.94 megabytes a minute, so a three-minute song is around 2.9 megabytes. A standard JPEG photo is 2 to 6 megabytes, a raw photo from a good camera can be 25 megabytes or more, and an hour of full HD video may use 3 to 7 gigabytes depending on the compression. Documents and spreadsheets are usually well under a megabyte, apart from those with many images. Use the converter to translate between units when you compare memory cards, phones and drives.

Key terms explained

A bit is a single binary digit and a byte is eight bits. A kilobyte, megabyte, gigabyte and terabyte are successive multiples. In the binary convention each step is 1,024, while in the decimal convention each step is 1,000. The binary prefixes kibi, mebi and gibi were introduced to avoid confusion. Storage capacity is the total space on a device, and usable space is smaller after the system takes its share. Compression reduces the size of files, and a backup is a separate copy of data.

Rules of thumb and quick checks

To convert megabytes to gigabytes, divide by 1,024, and the other way multiply. A drive sold as 1 terabyte shows about 931 gigabytes in binary units. An 8 gigabit memory chip is 1 gigabyte, since eight bits make a byte. Estimate how many files fit by dividing the capacity by the typical file size. Always keep free space of at least 10 to 15 percent on a drive, since a full drive slows down and risks errors.

Frequently asked questions