If this is your 1st year receiving self employed income calculating payments for quarterly taxes can be difficult. You can do a general assumption and pay 10, 15, 20 of income you received and send in as an estimate. You can also take a more measured approach and use the form Here. In the end when you file if you under paid based on your estimates you'll make it up with a final payment and if you over paid you'll end up with a refund. The 2nd year will be much better as you should receive vouchers that make recommendations to what the current year's payments should be.