Many Australians are being ripped off by mobile plans that carry three times more data than they actually use, the consumer watchdog says.

The ACCC published a report on Friday revealing the average mobile customer on a post-paid contract is using just 11.8 GB of data monthly.

Despite this, the median data cap they are paying for is 35 GB a month.

The ACCC said big telcos like Telstra, Optus and Vodafone are selling higher priced plans with 50 to 100 per cent more data in a move towards a so-called ‘more-for-more’ model.

“While consumers are getting more data allowance than before, it is unclear if they want or need it,” ACCC commissioner Anna Brakey said.

“An average person isn’t currently going anywhere near using the average mobile data allowance.”

Canstar Blue telco editor Tara Donelly said telcos are selling too much data to justify charging higher prices on entry-level plans.

“[Telstra, Vodafone, and Optus] are really pushing those high data plans, up to 500 GB,” Ms Donelly said.

“Vodafone launched completely unlimited data a couple of months ago.

“They are  wanting customers to jump on those plans … but most people don’t really need that much.”

How much mobile data do you need?

Finder senior telco and energy writer Mariam Gabaji said people think having more data than you need is like having a safety net.

But excess data usage fees are a thing of the past from the major providers of post-paid plans and many pre-paid providers allow you to bank unused data, Ms Donelly said.

“[When I] moved to Australia, I was like, ‘I want 100 GB mobile plan because it’s not that expensive, and I’m getting a good deal’,” Ms Gabaji said.

“But I ended up switching because I started tracking how much data I use [and] I found it was just 2 GB per month.”

Ms Gabaji said it’s “super simple” to find out how much data you use.

“People tend to forget that they could just use their mobile provider’s app to track how much data they’re actually using in a month,” she said.

“And you would probably notice you use way less than you thought.”

If you are on a prepaid plan, you can text your provider to find out how much data you have used, and most smartphone have features or apps that also keep track of your data usage.

Ms Donelly said many people overestimate the amount of data they use, especially during the pandemic, as people spent more time at home using their wi-fi.

How to find the right plan for you

Ms Gabaji said if you “set and forget” your mobile data plan, you could end up spending a lot more money than you need to.

If you’re planning to use more data for a short time, you can easily switch to a higher-data plan for a month, and then switch back.

“One out of eight [Australians] think switching providers is too much of a hassle, but it’s really not,” Ms Gabaji said.

“It’ll take max 10 minutes of your time to do it.”

When shopping around for a new plan, Ms Donelly said the two biggest things to keep in mind is how much you can comfortably afford to spend every month, along with how much data you use.

You should also think about how bigger isn’t always better when it comes to mobile data providers.

There are several smaller mobile data providers in Australia, and many are either owned by, or affiliated with, Telstra, Vodafone, and Optus.

These providers control more than 90 per cent of both the pre-paid and post-paid mobile markets.

“If you’re just someone that’s looking for … enough data to get you by, then you can definitely find something that’s comparable [to the major companies] by going to those smaller brands,” Ms Donelly said.

“And in terms of network coverage, all of the providers out there either use Telstra, Optus, or the TPG-Vodafone network.”

Ms Gabaji said if you have a pre-paid plan, you should also keep an eye on the recharge expiry period.

The ACCC found some people on pre-paid plans experienced price increases thanks to ‘stealthy‘ expiry period reductions from 35- and 42-days to 28 days.

Over a year, this effectively equalled a price rise of up to 50 per cent.