Does Wi-Fi Assist affect your cellular bill?

The Wi-Fi Assist feature added back in iOS 9 and available on iPhones and cell-equipped iPads backfills a low-quality Wi-Fi network, supplements one that you have a weak connection to, or covers outage gaps when your broadband service goes down. But, readers want to know, will it increase your mobile bill?

A few years ago, the answer (at least for U.S. residents) was: Probably. In 2022, however, it’s far less likely to be an issue.

First, Wi-Fi Assist only supplements on-device bandwidth use. If you’re using your iPhone or iPad as a Personal Hotspot, you’re already tapping the cellular network subject to limits and pricing set in your cellular plan.

Second, Apple doesn’t back all apps and services with Wi-Fi Assist. The company notes that Wi-Fi Assist helps “with most apps like Safari, Apple Music, Mail, Maps, and more.” That’s a bit vague, but it doesn’t mention video streaming, one of the heaviest bandwidth uses.

Third, a significant number of U.S. cellular subscribers have “unlimited” bandwidth on their cellular plans. That’s “unlimited” in quotation marks because cell companies don’t cut off or charge overages on these flat-rate plans, but rather throttle you to a low data rate (like 256Kbps or 3G speeds), or lower your priority among other users once you pass a fixed amount. It’s typically 5GB to 50GB per month per line. Other subscribers pay for fixed amounts of data, after which they’re cut off or have to pay additional fees for more usage that month.

So you’re likely to consume more bandwidth only if you’re routinely using a Wi-Fi network with poor performance and only face a consequence of it if that usage bumps your monthly total over a threshold or cap.

You can check your current usage of Wi-Fi Assist, which is turned on by default, by going to Settings > Cellular and swiping all the way to the bottom. My most recent consumption was 916KB—that’s just under one megabyte—while I used nearly 2GB directly on my phone. Tap the switch if you want to disable it.

This Mac 911 article is in response to a question submitted by Macworld reader Claire.

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