As a gig worker, how do I determine my quarterly gross income when they pay me weekly and the month end earnings will be paid out at the beginning of the next month?

[christinec02]

Should I wait for the statement and break it up? Does it count as earnings for the next quarter since it was paid out during the following month/quarter?

[Critter-3]

As a cash based taxpayer the income is considered taxable when it is recieved not when it is earned.  

[Hal_Al]

Q. As a gig worker, how do I determine my quarterly gross income?

Why do you think you need that information?  If it's for making quarterly estimated tax payments, the simple thing  to do is make 4 equal payments based on your prior year tax liability.  Most self employed people do it that way.