Comparing data, to minutes, to cost, to perks: which carrier is right for your family?

The wonderful world of wireless carriers can be confusing at the best of times. You might find cheap data with one, but it comes with expensive overage fees. Or one charges a low fee to add additional devices, but you can't bundle it with your home services.

When you're shopping between AT&T and T-Mobile it's important to know how much data you need, how many devices will be on your account, and how much data you expect to use.

What sharing plans are available from AT&T and T-Mobile?

Sharing plans allow you to purchase one big chunk of data and divvy it up between all the phones and devices on your account.

AT&T offers their Mobile Share Value plans. These plans are different sizes and allow you to choose exactly how much data you and your family need to share each month.

T-Mobile doesn't really offer a true sharing plan. Instead of sharing one big chunk of data, each person on your account is given a monthly allotment of data. Once they surpass their data limit, they can still use data on their phone or tablet, but their download speeds will be slower.

How many devices are allowed on a shared plan?

With both AT&T and T-Mobile you are charged for each device on your plan. Adding smartphones to your plan costs more than adding tablets or wearables, so knowing how many devices you want to share data with will impact your total bill each month.

AT&T cost per device

AT&T allows up to 10 devices to be on one of their shared plans. The cost of adding a device depends on how many GB of data you are sharing.

  • $25/month/smartphone (on plans with 5 GB or less of data)
  • $15/month/smartphone (on plans with 15 GB of data or more)
  • $10/month/tablet (no data restrictions)
  • $10/month/wearable (no data restrictions)
  • $20/month/laptop or hotspot device

T-Mobile cost per device

With T-Mobile you can have up to 12 devices on one account. The more devices you add, the cheaper it is per device (until you eventually bottom out at $10 each). Adding a tablet to your T-Mobile plan is only $10/device if you also have a cell phone on your plan, otherwise it's $20.

  • Phone 1, $50
  • Phone 2, $30
  • Phone 3, $10
  • Each additional phone $10
  • Each additional tablet $10 (or $20 if you don't have a phone)

Remember, if you're not bringing your own phone, your carrier will also charge you a monthly fee to purchase one of their phones. Costs vary, but if you want the most up-to-date phone, you'll be looking at about $25-$30 per month.

How does data work on a shared plan with AT&T and T-Mobile?

This is where things get tricky. AT&T lets your whole family share from one big pile of data, while T-Mobile gives you a specific data allotment for each device.

If you go over your allotted data on AT&T you get charged extra. If you go over on T-Mobile your data speed slows down, but you won't have to pay more.

AT&T monthly data rates

  • 300 mb, $20
  • 2 GB, $30
  • 5 GB, $50
  • 15 GB, $100
  • 20 GB, $140
  • 25 GB, $175
  • 30 GB, $225
  • 40 GB, $300
  • 50 GB, $375

Overage Charges: If you go over your allotted data on one of these plans you will be charged an additional $20/300 mb on the 300 mb plan, or $15/1 GB on all other plans.

Rollover Data: Unused data is rolled over into the next month and expires one month after rolling over.

T-Mobile monthly data rates

  • 2 GB (included with your monthly charge for each device on your account)
  • 6 GB, $15/device
  • 10 GB, $30/device
  • Unlimited, $45/device

Overage Charges: If you go over your monthly data limit with T-Mobile your connection speed can be reduced (If you have a normal, 4G, LTE connection your speed can be reduce from between 6 and 20 Mbps to between 64 and 128 kbps which is less than a 2G network connection). Even on an unlimited plan, if you exceed 25 GB on a device in one bill cycle your speeds may be reduced. This may only happen during peak use times, or if you're lucky, not at all, but T-Mobile reserves the right to limit your speeds if you go over.

Rollover Data: T-Mobile offers a service called Data Stash which allows you to rollover any unused data in future months and will save this unused, high speed data for an entire year.

How do talk and text work on a shared plan on AT&T and T-Mobile

Both AT&T and T-Mobile include unlimited talk and text with their shared plans.

With AT&T if you purchase a 15 GB or higher plan, you also get free talk and text to for Mexico and Canada.

T-Mobile includes unlimited talk and text to Mexico and Canada with no matter how much data you buy.

What perks come with a shared plan from AT&T and T-Mobile?

Sometimes it's tough to decide between one carrier or another, so each provider will offer something to sweeten the pot and hopefully make you choose them over someone else.

AT&T offers a popular TV service called DIRECTV, giving you access to local and network shows as well as a DVR. If you subscribe to this TV service, AT&T will give you unlimited data on for your cell phone, which could save you a lot of money each month depending on how much data your family uses. However, AT&T will slow down your connection if you use more than 22 GB of data between your mobile devices.

T-Mobile's incentive package helps protect your high speed data, by making certain data-draining activities exempt from your overall high speed data allotment. T-Mobile's Music Freedom allows you to stream music from popular services you already have an account with like Apple Music, Google Music, Pandora, without counting against your data. Binge On works the same way as Music Freedom, but for popular video services you have an account for like YouTube, Netflix, and Hulu.

Which carrier's shared plan is right for your family?

Both AT&T and T-Mobile have a lot of room to customize their services based on the needs and budget of your household. For comparison purposes, we will look at share plans that have two phones and two tablets on them.

If you want the absolute cheapest plan, that can be built with AT&T, but beware, this plan has an unrealistically low 300 mb of data to share, so you'd likely be paying their $20/month overage fee.

If you want the plan with most high speed data, you can get that with AT&T, but you're going to pay through the nose for it. T-Mobile let's you purchase an unlimited plan, but reserve the right to de-prioritize your access speed during peak times if you go over 25 GB on a device in a billing cycle.

If you want the best value for your data T-Mobile lets you buy the amount of data you think you'll need for each device and won't charge you overage fees.

If you have many devices consider the T-Mobile plan as it's per-device account fee bottoms out at $10 for three or more devices, which is less expensive than AT&T's rates.

If you want to avoid overage fees then T-Mobile is a clear winner since they only slow down your data if you go over your limit instead of charging you per GB of data.

If you're primarily concerned with talk and text from your provider, AT&T and T-Mobile are pretty equal. The only difference is if you frequently talk or text with people in Mexico or Canada, you need to have a minimum GB plan with AT&T (starting with the 15 GB plan for $100) whereas with T-Mobile, it's included for any data amount.

If you already pay for TV service in your home you might find more value with AT&T depending on how much data you use in a typical month.

Keep calm and carrier on

Ultimately choosing a shared plan for your family comes down to how many people are in your home, what devices they use, and what they use them for. AT&T and T-Mobile have slight advantages between each other depending on what category you look at.

Overall T-Mobile's plan offers the most customization and flexibility whereas AT&T is a good option if you are pretty consistent month-to-month in the way you use your data and devices.