I hope this is the right place to ask this:

I intend to buy a new router, but now I am confused about the difference between dBm and dBi.

I have have two routers in head, one of them is 2dBi and the second one is 20dBm.

Which one has better range?

Could you give me how many percent is the range of one of them in compare to the other one?

And how that conversion can be done and how to estimate the range depending on those given numbers?


The two routers are: TP-Link-TL-WR1043ND-V3 and GL-MT300A

What I need is to know which router has bigger WiFi range?

  • 2
    They are entirely different units. Your trying to compare an Apple to an Orange and asking us which one is better. You can convert the units but you didn't supply any of the required variables in order to do so. Come into our chat to discuss this more we can get specifics and just help you decide
    – Ramhound
    Dec 29, 2016 at 0:16
  • @Ramhound, I added the two routers I was trying to choose between to the question, maybe you can get the paramters you need? Dec 31, 2016 at 12:31
  • 1
    GL-MT300A has zero range because it's not a wireless router
    – Ramhound
    Dec 31, 2016 at 15:15
  • 1
    TP-Link-TL-WR1043ND-V3 has the range of any 802.11n router
    – Ramhound
    Dec 31, 2016 at 15:16
  • @Ramhound but then why does the first one have antennas? Dec 31, 2016 at 20:31

2 Answers 2


20 dBm is a measurement of power (100 milliwatts, to be precise).

2 dBi is a measurement of the antenna's performance, relative to an imaginary isotropic radiator.

They are two entirely different dimensions, and cannot be 'compared' in any meaningful way.


The difference is that dBi is a "Relative" value (Think measurement between my house and your house, or of how much water was in the tank before and how much is in the tank now) of the "gain" of the antenna - A factor you can increase, for example, by attaching a larger antenna such as a cantenna to your wifi setup. The dBm refers to the absolute power of the antenna (How many milliamps are flowing to it) - Higher is better, and it's something capped by regulatory agencies, but you can increase it if you hack your router's firmware to break the law (Something I don't suggest you do, but I can't stop anyone either!)

  • That said - If you're looking to increase the range of your wifi, you can do it much easier if you have a wifi adapter which has the ability to EASILY extend it to, say, the roof or something, with a long cable before it reaches the part with the antenna in it - Example here, though these guys take it apart to get that kind of functionality: youtube.com/watch?v=6odNBrwRM1k
    – Dmitri DB
    Dec 29, 2016 at 0:29
  • Or, you know, an Ethernet-connected AP... Dec 29, 2016 at 0:53
  • Those are always nice but they sure don't beat a directional antenna
    – Dmitri DB
    Dec 29, 2016 at 1:28
  • OTOH, they do easily beat trying to cover the whole house with a single overpowered "wireless router." Dec 29, 2016 at 5:50
  • I made a cantenna by whacking a coffee can with a garden backhoe a few times until a hole appeared big enough to run a usb wire through. The dongle is held in there with blu-tac. Works wonders and took me less than 10 minutes of effort, looks ugly as can be just the way I like it!
    – Dmitri DB
    Dec 29, 2016 at 5:53

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