How many megabytes are in a terabyte?

Using the SI decimal standard: 1 TB = 1,000,000 MB (one million megabytes). Using the IEC binary standard: 1 TiB (tebibyte) = 1,048,576 MiB (mebibytes). Storage manufacturers use TB; most operating systems use TiB but often label them "TB."

Why does my 1 TB hard drive show less space in my OS?

The manufacturer rates it in SI terabytes (1 TB = 1,000,000,000,000 bytes). Your OS reports in tebibytes (1 TiB = 1,099,511,627,776 bytes) and calls them "TB" or "GB." A 1 TB drive holds about 0.909 TiB, so it appears as roughly 931 GB in most operating systems.

What is the difference between MB and MiB?

MB (megabyte) follows the SI decimal system: 1 MB = 1,000 KB = 1,000,000 bytes. MiB (mebibyte) follows the IEC binary system: 1 MiB = 1,024 KiB = 1,048,576 bytes. 1 MiB is about 4.86% larger than 1 MB.

How do I convert terabytes to megabytes?

Multiply the terabyte value by 1,000,000 to get SI megabytes (MB). Multiply tebibytes by 1,048,576 to get binary mebibytes (MiB). For storage hardware, the SI formula (×1,000,000) matches the advertised specs.

How many megabytes is 2 TB?

2 TB = 2,000,000 MB using the SI decimal standard. In binary terms, 2 TiB = 2,097,152 MiB.

How accurate is this converter for very large values?

The converter uses JavaScript 64-bit floating-point (IEEE 754 double precision), which handles integers exactly up to 2^53 — about 9 quadrillion. For any practical storage size in terabytes, the result is exact.

Terabytes to Megabytes Converter

Name: Terabytes to Megabytes Converter
Availability: InStock
Author: Nham Vu

Enter a terabyte value and instantly get megabytes (MB, decimal SI) and mebibytes (MiB, binary IEC), plus a quick-reference table.

Input — Terabytes

Number of terabytes

SI vs. binary: 1 TB (terabyte, decimal) = 1,000,000 MB. 1 TiB (tebibyte, binary) = 1,048,576 MiB. Storage specs use TB; your OS reports TiB (but often labels them "TB").

Results

Enter a terabyte value and click Convert.

Reference Table — Common Terabyte Counts

Quick lookup for typical drive and storage sizes.

Terabytes (TB)	MB (SI, ×1,000,000)	MiB (binary, ×1,048,576)	Typical example

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Summary

Enter a terabyte value and instantly get megabytes (MB, decimal SI) and mebibytes (MiB, binary IEC), plus a quick-reference table.

How it works

Enter the number of terabytes in the input field.
The tool multiplies by 1,000,000 to get decimal megabytes (MB, SI).
It also multiplies by 1,048,576 to get binary mebibytes (MiB, IEC), treating the input as tebibytes.
Results appear instantly with up to 10 significant digits.
Use the copy buttons to grab any result value.
Scroll down for a reference table of common terabyte counts in MB and MiB.

Use cases

Find out how many megabytes a hard drive or SSD rated in terabytes actually holds.
Understand why a "1 TB" drive shows less space in your OS (SI vs. binary units).
Convert cloud storage quotas from terabytes to megabytes for detailed planning.
Translate backup or archive sizes into megabytes for quota and billing estimates.
Verify storage specs when comparing drives rated in TB against OS-reported figures.
Cross-reference OS-reported sizes (MiB) against hardware specs (MB) for large datasets.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu