Gigahertz to megahertz: reading a channel table properly
What this conversion does
It multiplies by a thousand, turning a frequency written in billions into one written in millions. The two are the same number of cycles per second, and the conversion matters because Wi-Fi channel plans are published in megahertz while most consumer equipment is marketed in gigahertz. A device described as 2.4 GHz and a channel listed at 2412 MHz are not in conflict — they are the band name and the channel.
Why the band name is not a frequency
The label 2.4 GHz describes a region of spectrum, not a point inside it. The channels in that region begin at 2412 MHz and continue in five-megahertz steps, so the named figure is below every channel it covers. Similarly, the 5 GHz band contains channels that are mostly above 5 GHz. Reading a band name as though it were a channel is the most common way to end up describing a frequency nothing actually transmits on.
Gigahertz to megahertz conversion table
The commonly used Wi-Fi channels in both units, with the band names shown beside them to make the difference between a label and a channel explicit.
| Gigahertz (GHz) | Megahertz (MHz) |
|---|---|
| 1 | 1000 |
| 2.4 | 2400 |
| 2.45 | 2450 |
| 5 | 5000 |
| 5.8 | 5800 |
| 24 | 24000 |
Channels that overlap by design
In the 2.4 GHz region, channels are five megahertz apart but each transmission is around twenty megahertz wide, so adjacent channels interfere with each other. Only three channels in the region do not overlap. This is arithmetic on the megahertz figures, which is why the channel table is published in that unit and why the conversion from gigahertz is needed before the arithmetic can be done at all.
A thousand, and the decimals survive
Multiplying by a thousand moves the decimal point three places right, so 2.412 becomes 2412 and 5.18 becomes 5180. Because the shift is by a power of ten, no digits are added or lost — a channel that ends in a fractional megahertz keeps that fraction.
Frequently asked questions
How do I convert gigahertz to megahertz?
Multiply by a thousand. So 2.412 GHz is 2412 MHz, and 5.18 GHz is 5180 MHz. The multiplication moves the decimal point three places to the right and is exact.
Is 2.4 GHz the same as 2400 MHz?
Arithmetically yes, but no Wi-Fi channel sits at 2400 MHz in most of the world. Channel 1 is at 2412 MHz, and the small gap below it keeps the transmission clear of other users of the band. Treat 2.4 as a label and 2412 as a frequency.
Why is channel 1 at 2412 and not 2400?
Because the band was allocated with a margin at the bottom edge, and the channel numbering inherited that offset. The five-megahertz channel spacing then continues from there, giving 2412, 2417, 2422 and so on.
Which Wi-Fi channels do not overlap?
In the 2.4 GHz region, only three of the fourteen channels are free of overlap with each other, because each transmission is about twenty megahertz wide while the channels are only five apart. Working out which three requires the channel frequencies in megahertz.
Does the converter work for the 5 GHz band?
Yes, and for the 6 GHz band too. Frequencies there convert by the same factor, so 5180 MHz is 5.18 GHz and 5955 MHz is 5.955 GHz. The tool is not limited to any particular band or standard.