What Do Router AC Ratings Like AC1200 and AC3200 Mean?

Wi-Fi is steadily getting better. The move from 802.11n to 802.11ac is well underway, and we may soon see 802.11ad (much faster) and 802.11ax (advanced bandwidth management) making it into the mainstream. Right now, your best option is still 802.11ac, but not every AC router is created equal.

There are numbers attached to the end that tell you the theoretical maximum speeds — AC1200, AC1900, AC5300, etc. These numbers claim to refer to how many megabits per second (Mbps) you can get from the router, but in practice, you’ll want to take the “theoretical” part of “theoretical maximum” pretty seriously.

If you look at your router’s model number, you will always see a term like “AC 1200,” “AC 1900,” etc., regardless of the brand of the router. So what does this mean? The number behind the “AC” actually refers to bandwidth.

ac-routers-numbers

Take an AC1200 router, which maxes out its bandwidth at 1200 megabits per second, or 1.2 gigabits per second (Gbps). Since eight bits equals one byte, a 1200 Mbps connection would be enough to download about 150 megabytes per second – enough to get a whole movie in half a minute.

So, since the current maximum speed for most people is 1 Gbps (if you’re lucky enough to have a good Internet connection), why would anyone bother getting an AC5300 router? AC1200 already seems like overkill. The short answer: because neither router actually gets you past 1 Gbps, and it’ll probably get you much less.

ac-routers-sum

The number after the AC actually refers to the sum of all the bandwidth that can theoretically be delivered by each band/frequency that the router uses. If a router has two bands (2.4GHz and 5GHz, which are the standard bands used for Wi-Fi), one of the bands may claim a maximum of 450 Mbps and the other 1300 Mbps – 1750 in total. You can get higher AC numbers by having bands with higher throughput ratings (1733 Mbps is pretty popular) or by adding more bands.

Here’s the catch, though: your devices can probably only connect to the signal from one band at a time. If your computer is connected to the 1300 Mbps band, the other band won’t be giving you 450 more Mbps. It’ll just go unused. Getting a router with more bands (and thus a higher sum of theoretical maximums) won’t really do much for speed.

ac-routers-test

So you’re limited to one band per device, but still, if a router is advertising 1300 Mbps throughput on one of its bands, that’s impressive. Unfortunately, you won’t be getting that speed either, since those numbers are gathered under ideal testing conditions, not in the real world.

The hardware and software they use are high-end and fully optimized for the test, with only one device connected at a time, and at short distances. In short, normal people probably will never see the advertised theoretical maximum show up on their own speed tests.

Because setups and environments vary so much, there’s no sure-fire way to tell how much speed you can really expect from a router, but in general, even under ideal conditions, getting more than 70% of the advertised speed, or up to 6 – 700 Mbps, isn’t likely.

More realistically, a mid-range AC1200 router will deliver around 300 or 400 Mbps on a good day, and upgrading to something fancier will probably deliver marginal speed gains at best.

ac-routers-connections

But just because higher AC numbers don’t make your connection faster doesn’t mean that they’re useless. A model with a big number will generally have more antennas and bands (but not necessarily faster ones) and maybe better features, with newer technology like MU-MIMO (Multiuser, Multiple-Input, Multiple-Output) allowing more users to connect to a router without suffering speed losses.

A four-antenna AC5300 router could handle four bandwidth-heavy users without the slowdown that conventional routers might get. In addition, the higher the number on the band you’re connected to, the more data it can handle from multiple devices. If you’ve only got a few devices using a bit of bandwidth though, a lower-powered AC router will handle your traffic just fine.

In the end, the number that you see after the AC is pretty close to meaningless. It’s the sum of the very theoretical maximum speeds of multiple bands that you can’t connect to simultaneously, and it really only gives you a hint about how it might be able to handle more computers at once.

To get an idea of a router’s actual speed, buyers are better off checking reviews and looking for real-world testing data. Given that gigabit-speed Internet is still quite rare, though, not being able to get past 500 Mbps isn’t really an issue for most people – and if it is, there’s always the old Ethernet cable standby, and we’re getting closer to gig Wi-Fi all the time.

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