At the bottom of your account register, you’ll see the Totals Window:
Here you’ll see three numbers:
Uncleared Transactions - This represents all the transactions you’ve entered into your register that the bank doesn’t know about yet. They haven't 'Cleared' the bank yet.
The balance you see on the account tab is the working balance.
The working balance will NOT match your bank balance if there are uncleared transactions. But since those transactions took place, you need to consider them when thinking about how much money you really have.
The working balance is the most important one since it represents what you really have after everything clears the bank.
Your bank balance is $250. You go shopping for a day and make three stops:
Groceries - $70
Gas - $45
Restaurant - $25
When you get home, you open up YNAB and enter the spending that you know you just did. If you log into your bank and don't see them yet then they haven't cleared as the bank does not know you spent the money yet.
The next day you log in again and see that the grocery trip and the gas purchase have cleared the bank. Then you mark them cleared in the account register.
You can do this by clicking the "C" on the right side of each transaction to change it from grayed out to green.
Now the cleared balance in the Totals Window should match your online bank. However the working balance is $110.
You’ll see that on the account tab, too.
That restaurant transaction was spent, so you know the money is gone. By entering it now, it’s subtracted from your restaurant category, giving you up-to-date information on what you have left for restaurants.
By leaving it uncleared, you acknowledge the bank doesn’t know about it yet. This way, you can reconcile the account even though not everything has cleared.