How many KB are in 1 MB?

In the binary system (used by operating systems), 1 MB = 1,024 KB. In the decimal system (used by storage manufacturers), 1 MB = 1,000 KB. Most people and computers use the binary definition.

How many MB are in 1 GB?

In binary, 1 GB = 1,024 MB. In decimal, 1 GB = 1,000 MB. When your OS shows file sizes, it uses the binary system (1,024 MB per GB).

What is the difference between MB and Mb?

MB (uppercase B) stands for Megabyte (data storage), while Mb (lowercase b) stands for Megabit (data transfer speed). 1 MB = 8 Mb. Internet speeds are typically advertised in Mbps (Megabits per second), while file sizes are measured in MB (Megabytes).

Why does my hard drive show less storage than advertised?

Storage manufacturers use the decimal system where 1 TB = 1,000,000,000,000 bytes. Operating systems use the binary system where 1 TB = 1,099,511,627,776 bytes. So a '1 TB' drive shows as approximately 931 GB in your OS. This ~7% difference is not missing space — it's a measurement discrepancy.

What is the difference between binary and decimal data units?

Binary uses powers of 1024 (2^10): 1 KB = 1,024 bytes, 1 MB = 1,048,576 bytes. Decimal uses powers of 1000 (10^3): 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes. The IEC introduced unambiguous prefixes (KiB, MiB, GiB) for binary units, but they haven't gained widespread adoption.

How do I convert MB to KB?

To convert MB to KB, multiply by 1,024 (binary) or 1,000 (decimal). For example, 5 MB = 5,120 KB in binary, or 5,000 KB in decimal. Use our converter above for instant, accurate results.

How long does it take to download 1 GB?

It depends on your internet speed. On a 100 Mbps connection: about 80 seconds. On a 50 Mbps connection: about 2.7 minutes. On a 1 Gbps connection: about 8 seconds. Remember, internet speeds are in megabits (Mb), not megabytes (MB), so divide by 8.

What comes after Terabyte?

The order from smallest to largest is: Bit → Byte → Kilobyte (KB) → Megabyte (MB) → Gigabyte (GB) → Terabyte (TB) → Petabyte (PB) → Exabyte (EB) → Zettabyte (ZB) → Yottabyte (YB). Each step is 1,024× (binary) or 1,000× (decimal) larger than the previous.

Data Size Converter

Enter Size

1 KB = 1,024 bytes — used by OS, RAM, file sizes

1 GB =

1,024MB

Standard: Binary (1 KB = 1,024 B)

All Units

1 GB in every unit (binary)

Binary vs Decimal

Why your hard drive shows less space

1024

Binary (OS Reports)

1,073,741,824 bytes

1000

Decimal (Manufacturer)

1,000,000,000 bytes

Difference: 6.9% — this is why a "1 TB" drive shows ~931 GB in your OS

Transfer Time

Estimated time to transfer 1 GB

4G LTE (50 Mbps)2.7 min

5G (500 Mbps)16.0 sec

Wi-Fi 5 (400 Mbps)20.0 sec

Wi-Fi 6 (1 Gbps)8.0 sec

100 Mbps Broadband1.3 min

Gigabit Ethernet8.0 sec

USB 2.0 (480 Mbps)16.7 sec

USB 3.0 (5 Gbps)1.6 sec

How to Use This Data Size Converter

Convert between Bytes, KB, MB, GB, TB, PB and Exabytes instantly

Choose Binary or Decimal

Binary (1024) is what your OS uses; Decimal (1000) is what manufacturers use.

Enter the size

Type the data size amount you want to convert.

Pick From and To units

Select units from the dropdowns, or swap them with the arrow button.

See all units at once

The converter shows your value in every unit simultaneously. Click any row to copy.

Check transfer times

See how long it would take to transfer at various connection speeds.

Data Size Reference Tables

Binary (1024-based) vs Decimal (1000-based) — the two standards compared

Binary Standard (1024-based)

Used by operating systems, RAM, and file sizes in Windows/macOS/Linux.

Unit	Bytes	Bits
Kilobyte (KB)	1,024	8,192
Megabyte (MB)	1,048,576	8,388,608
Gigabyte (GB)	1,073,741,824	8,589,934,592
Terabyte (TB)	1,099,511,627,776	8,796,093,022,208
Petabyte (PB)	1,125,899,906,842,624	—

Decimal Standard (1000-based)

Used by hard drive manufacturers, SSDs, network speeds, and the SI standard.

Unit	Bytes	Bits
Kilobyte (KB)	1,000	8,000
Megabyte (MB)	1,000,000	8,000,000
Gigabyte (GB)	1,000,000,000	8,000,000,000
Terabyte (TB)	1,000,000,000,000	8,000,000,000,000
Petabyte (PB)	1,000,000,000,000,000	—

Data Size Conversion Formula

How the two-step base-unit method works

Step-by-Step Method

This converter uses bytes as the base unit. Every conversion happens in two steps:

Step 1: bytes = value × base^exponent[from_unit]Step 2: result = bytes ÷ base^exponent[to_unit]where base = 1024 (binary) or 1000 (decimal)

Example: Convert 5 GB to MB (binary)
Step 1: 5 × 1024³ = 5,368,709,120 bytes
Step 2: 5,368,709,120 ÷ 1024² = 5,120 MB

Quick shortcut: To convert GB → MB (binary), just multiply by 1,024. To convert MB → KB, multiply by 1,024 again. Each step up is ×1,024 (binary) or ×1,000 (decimal).

Common File Sizes in Real Life

How much space do everyday files actually take?

Text email

1–5 KB

Word document (10 pages)

50–100 KB

MP3 song (4 min)

3–5 MB

Smartphone photo

3–8 MB

HD video (1 hour)

3–5 GB

4K movie (2 hours)

15–25 GB

AAA video game

50–150 GB

Full OS install

20–60 GB

Bits vs Bytes: Why Internet Speeds Are Confusing

Understanding Mbps (speed) vs MB/s (file download)

Internet speeds are advertised in bits per second (Mbps), while files are measured in bytes (MB). Since 1 byte = 8 bits, you divide your speed by 8 to find your actual download rate:

50 Mbps (4G LTE)

= 6.25 MB/s download

1 GB file ≈ 2.7 minutes

100 Mbps Broadband

= 12.5 MB/s download

1 GB file ≈ 80 seconds

500 Mbps (5G)

= 62.5 MB/s download

1 GB file ≈ 16 seconds

1 Gbps (Gigabit)

= 125 MB/s download

1 GB file ≈ 8 seconds

Remember: ISPs advertise in bits because the number looks 8× bigger. When your ISP says "100 Mbps", your actual file download speed is ~12.5 MB/s.

Why Your Hard Drive Shows Less Space Than Advertised

The binary vs decimal discrepancy explained

Hard drive manufacturers use the decimal system (1 TB = 1,000,000,000,000 bytes), but your operating system uses binary (1 TB = 1,099,511,627,776 bytes). This means every drive "loses" about 7–9% of its advertised capacity when you check in your OS:

Advertised	Actual (OS)	"Lost"
128 GB	~119 GB	7.0%
256 GB	~238 GB	7.0%
512 GB	~477 GB	6.8%
1 TB	~931 GB	6.9%
2 TB	~1.82 TB	9.1%
4 TB	~3.64 TB	9.1%

Note: This space isn't actually "missing" — it's the same physical storage. The discrepancy is purely a measurement difference. Additionally, your OS reserves some space for formatting and system files, reducing usable space further.

The Data Size Hierarchy

From the smallest bit to massive exabytes — every unit explained

Bit(b)

The smallest unit — a single 0 or 1

1 bit

Byte(B)

8 bits — represents a single character (letter, digit, or symbol)

8 bits

Kilobyte(KB)

A short email or a few paragraphs of plain text

1,024 B

Megabyte(MB)

A high-res photo, an MP3 song, or a short document

1,024 KB

Gigabyte(GB)

An HD movie, a large app, or ~250 smartphone photos

1,024 MB

Terabyte(TB)

A large hard drive — stores ~250,000 photos

1,024 GB

Petabyte(PB)

Data center scale — Netflix stores ~60 PB of content

1,024 TB

Exabyte(EB)

Global scale — internet traffic is hundreds of EB per year

1,024 PB

IEC Binary Prefixes: To avoid ambiguity, the IEC defines KiB (1,024 B), MiB (1,048,576 B), GiB (1,073,741,824 B), and TiB (1,099,511,627,776 B) — used in Linux and technical docs.

Fun fact: The entire Library of Congress is estimated at 10–20 petabytes. A single modern data center can store more than that.

Frequently Asked Questions

Common questions and detailed answers

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Last updated Mar 24, 2026