Is it normal for Wifi to be this much slower than ethernet?

[Evoke186]

i got my internet fixed today (was going 0.7 mbps before) and also upgraded my internet speed, so now when i'm directly connected to the ethernet i get about 39 mbps and i pay for 40, so that's great.

however when i'm on wifi i only get about 16-19 mbps. is this normal? i know wifi is supposed to be slower than ethernet, but that's half the speed of the ethernet. also, is that considered a good or bad internet speed in general?
thanks for the answers, and i said mbps not mb/s haha. i have 802.11n. i used to pay for 20 mbps, but today i upgraded to 40 mbps for $10 extra per month. should i consider paying another $10 per month for 80 mbps?
the devices i have that are normally connected to wifi are: a PS3, PS4, laptop, 2 smartphones and 2 tablets. should i get 80 mbps for that?

[t2kmf]

There are a lot of variables to what actually causes wifi to be slower. It could depend on signal quality, number people on the wifi (including unwelcome guests), QoS prioritization, or overall crappiness of the wifi capabilities of the wireless router. Wireless didn't get that good until the last few years. If your router is old then that could be the reason.

The numbers you are quoting are in the normal to low range though.

[L337-H4x0r]

As t2kmf said, there are a lot of variables. One thing to keep in mind is the position of your router. Ethernet will ALWAYS be faster than wireless. Also, please realize that internet speed is measured in megabits per second (Mb/s) and not megabytes per second (MB/s), there are 8 bits in a byte so that is a significant difference. You say you are getting 39 Mb/s which is outstanding if you are actually getting that speed. But with that said, you almost never get the speed your computer is telling you you're getting. The speed your computer is telling you is the connection speed between the router and your computer, which is why I get speeds of up to 300 Mb/s with my wireless card every so often despite only paying for 25 Mb/s. My computer is communicating with the router at 300 Mb/s but my router is only capable (due to the limits set by my ISP) of communicating with the rest of the internet at a speed of up to 25 Mb/s.

Your wireless speed is also dependent on the wireless standard you are using, if it's 802.11b, 802.11a, 802.11g, 802.11n, or 802.11ac. I listed them in order of increasing speed. AC can support speeds of over 1 Gb/s at top speed (which is rarely achieved), N can get up to 300 Mb/s, G up to 54 Mb/s, A up to 54 Mb/s (at much shorter distances than G), and B up to 11 Mb/s.

So taking into account these caps if you are running a G network and are between midway and at the edge of the network a speed of 16-19 Mb/s is actually quite good. But there are many different variables including distance, obstacles, band interference (such as from microwaves, radios, other networks, etc), multiple devices using the wireless, and more.

If you have more questions feel free to contact me directly, assuming you feel my answer was appropriate and adequate.

EDIT:
Mbps and Mb/s are the same things, just different ways of writing it. They both stand for megabits per second.

Also, unless you are a major power user, have a lot of users on your network, or constantly have more than 5 devices streaming media 40 Mb/s is more than sufficient. In fact, as long as you actually get that speed it's more than adequate for 90% of home users. So in my humble opinion upgrading to 80 Mb/s would be a waste of money as you will be paying for a lot of unused bandwidth. As for your router, check in the settings and make sure it is using the 2.4 Ghz band to increase travel distance. There are other settings that you could fiddle with as well but without knowing your current settings or router model there is no way for me to judge what settings you should change. The lower speeds are most likely caused by interference or obstacles. Check your connection speed when you are sitting next to your router if you can. If they are faster it is a distance/obstacle issue. One setting that might help fix this would be to change the channel your router is broadcasting on to 1, 6, or 11.

[slin100]

16-19 Mbps is a fairly common real-world speed for 802.1g Wi-Fi. If you want to increase the speed of your Wi-Fi, then you may have to step up to 802.1n or 802.1ac. You may need to upgrade to a new wireless router.

If you are living in the U.S., an Internet speed of 16-19 Mbps is around average and may be perfectly fine for one computer/tablet/smartphone device. If you have several devices that, collectively use all 40 Mbps, then great. If you are really only using 19 Mbps, then you are wasting your money.