Your first $14,600/year of income is tax-free, so since you're paid every other week you can just immediately subtract $561 from your pay amount. There's no tax on that. The next $11,600/year is taxed at 10%, which is $446 per paycheck. Your checks are always more than this, so you're just paying $44.60 on the whole $446. Easy. That leaves a bunch of income taxed at 12%. There are higher income brackets, of course, but not for your checks. You can simplify your spreadsheet calculation quite a lot. You are always paying $44.60 on the first $1,007 of income (that's 0% of $561 and 10% of $446), and 12% on the rest. Spreadsheet formula: ((gross pay minus $1,007) times 12%) + $44.60. Obviously if you ever earn significantly more or significantly less than you're seeing on the two checks you reported here, this does not work. But if your checks are all more than $1,007 and less than about $2,270 this is a perfectly good simplification. More on reddit.com

Paycheckcity and ADP as well as a number of other sites have net pay calculators. You will need to know your settings on the W4, the California equivalent, as well as any local taxes or other deductions for things like retirement, health insurance, etc. More on reddit.com

Using the paycheck calculator at https://www.paycheckcity.com/calculator/salary#select-state-calculator will let you see what would get withheld from your paycheck if you were updated to a CA resident. Would that work for what you need? More on reddit.com

Here are sample values of what the answers should be But what are the answers instead? This may be more of a question for r/tax . More on reddit.com