Well that's what I'm trying to figure out, my calculations for all of the stache is around $400K, but Mint is telling me it's $722K, and that just sounds wrong. All the numbers are right, I included my really old car worth 2K. I just don't think this number is correct. My FIRE goal is 500K with paid off house (100k home) so total of $600K. Own some stock, but most of the stache is in real estate. I know I have about 2 more years left before FIRE.
I had something similar happen. It wasn't 'obviously' double counting, but when I really dug through the numbers it was.
Example.
Roth 401k 100k
401k 300k
The 300k includes the 100k. These numbers might not appear in the same location. I've also had it keep track of a closed account assuming the last balance. Basically the account was 0, but Mint kept showing it as $14,000 updated 46 days(and counting) ago. Lets say you rolled the 401k over to Vanguard 6 months ago.
Vanguard
IRA: 500k(includes the 300k)
YZX company updated 189 days ago
Roth 401k: 100k
401k: 300k
Your Net Worth in this situation is actually 500k, but Mint is showing it as 900k.
Those are my only guesses other than not counting some debt accounts.
I don't use Mint anymore since I found Personal Capital. Personal Capital is so much more detailed, especially when it comes to investments. It was like switching from ping pong to tennis.
I like PC for investments, but for budgeting I found it to be a joke. It kept double counting purchases and it never actually tagged purchases correct like Mint does. That might just be my experience though. For me it was easier(and faster) to just maintain Mint for tracking cash flow and have PC for tracking investments than it was to go into PC and correct all the transactions.
EDIT: To be more specific about Personal Capital's error. It reported I had spent $19,113 over the course of a 'month.' When I went through the transactions I noticed it had double counted several items, it counted my credit card purchases as spending and then it also counted paying those cards off as more spending, and it counted all IRA/401k/HSA contributions as spending, and once the money was in those accounts it counted buying an ETF as even more spending. Mint reported I spent 2104 for the month.