Data usage higher than it should be.

Hey there! The data recorded is only going to show what the SIM card requests from the network. What kind of data activities do you do on your phone specifically?

Unusual data usage is almost always the result of a rogue app, website, or browser causing the issue.  You should be able to see which app(s) are using the excess data.

Chris - thanks for the reply. I was not expecting that at all.

Long story short: my usage has been way higher the last two months than it's ever been before and I can't explain it. I used to do a lot of hotspot work and regular phone stuff and never had an issue even with a 5 GB cap.

The last month I used my 10 GB in two weeks and I assumed it was due to my computer downloading some update.

Fast forward to today and I've used over 2GB of data in 5 days. None of that is streaming anything. Just basic surfing and email on my phone.

To me it seems like I am using data way faster than before but I'm actually doing less with my account. It's frustrating and it seems like it's a way to make me go up to the unlimited plan (before the 10 GB was more than enough).

Yes.  TMo doing some funky "calculations" here.  I don't use my phone much except for email/web surfing.  Don't stream, and for 99% of the time, I am on WiFi.  These past couple months, TMo has been completely falsifying my data usage.  My phone is only reporting 419MB of mobile data usage.  Yet, somehow, according to TMo, I used 4.7GB.  I can understand small differences in data usage.  But TEN times the amount reported?  Yeah, ok.  what kind of crap is this.  In all the years I have been with TMo, never had a problem until these past few months. 

And my highest data using app this month is:  YouTube at 183MB

Month Before: Reddit at 330MB

Month Before that:  Reddit 600MB

Shouldn't be anywhere near 5GB lol

Does that include system apps? 

Yes.  Most of my usage is done on WiFi.

What does your phone report as the usage for the month (or month to date).  Also, i usually align the billing cycle to reset the phone data counter and they match pretty well (few MB or so) when i compare.

7 days in, my phone says 1.0GB and My T-Mobile says 0.89GB.

Galaxy S9+

I am having the same experience as the OP.  Our data went from 30-40 to 75gb last month.  Today, one phone put on 4gbs of data and I remember using a phone nonstop all month long and struggling to get more than 3gb for the whole month. My phone reports the data usage as 25-30% of what TM says I used.  I would like answers to this.  Our data habits haven't changed.   I fell that TM is pushing hard for customers to switch to Magenta Max and therefore padding everyone's usage to encourage them to make the switch.  I don't feel this is ethical.  

My phone said I used about 6gb last mouth (I used the hotspot on vacation) but TM said I used over 13gbs!  

I am having the same problem with my Franklin T-9 Hotspot device. I'm signed up for the max of 50GB high-speed data per month, then after that it goes to slow-speed which is useless to me. This month, after only one week, it went to slow-speed, and my device says I've used 16GB, but T-Mobile says I've used 52GB!!  I understand that there could be a small discrepancy,  but this is ridiculous. I know I haven't used that much data already. I live in the country and have no other option for wi-fi. Any ideas? Has anyone else had this problem with the T-9?