Gigabits to Megabits
Type a value in either box to convert between gigabits and megabits. The factor is 1000.
| Gigabits | Megabits |
|---|---|
| 1 Gb | 1000 Mb |
| 2 Gb | 2000 Mb |
| 3 Gb | 3000 Mb |
| 5 Gb | 5000 Mb |
| 10 Gb | 10000 Mb |
| 25 Gb | 25000 Mb |
| 50 Gb | 50000 Mb |
| 100 Gb | 100000 Mb |
How to use
- Enter a value in the Gigabits field.
- The Megabits figure appears immediately — no button to press.
- Typing in the Megabits field converts back to Gigabits the same way.
- Use the reference table for the values that come up most often.
Gigabits to Megabits formula
Converting gigabits to megabits is a single multiplication by 1000.
Mb = Gb × 1000
Put another way, one gigabit is exactly 1,000 megabits.
Why this factor: the gigabit and the megabit are both defined against the byte, so dividing one definition by the other gives 1000 directly. Both definitions are set out in full below.
To go the other way, divide by 1000 — or use the Megabits to Gigabits converter, which is the same calculation reversed.
Worked example
Given 4 Gb, multiplying by 1000 yields 4000 Mb.
4 Gb × 1000 = 4000 Mb
The converter above does this for any value you type, in either direction.
What is a gigabit?
A gigabit is one billion bits, the unit of modern high-speed networking.
Definition: Exactly 1,000,000,000 bits, so exactly 125,000,000 bytes.
Where it is used: Gigabit Ethernet, fiber broadband tiers, and data-centre interconnects.
What is a megabit?
A megabit is one million bits — the unit internet speeds are advertised in.
Definition: Exactly 1,000,000 bits, so exactly 125,000 bytes.
Where it is used: Broadband speed tiers and video streaming bitrates, quoted as Mb/s or Mbps.
Worth knowing: Divide advertised megabits per second by 8 to get the megabytes per second a download will actually show.
Gigabits vs Megabits
The gigabit and the megabit belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many megabits are in a gigabit?
One gigabit equals 1000 megabits.
What is the formula to convert gigabits to megabits?
Multiply the number of gigabits by 1000. To reverse it, divide by 1000 instead.
How do I convert megabits back to gigabits?
Divide by 1000, which is the same as multiplying by 0.001.
How many megabits are in 10 gigabits?
10 Gb works out to 10000 Mb.
Is there anything to watch out for with megabits?
Divide advertised megabits per second by 8 to get the megabytes per second a download will actually show.
How is the gigabit defined?
Exactly 1,000,000,000 bits, so exactly 125,000,000 bytes.