Estimated Tax Payments when you have retirement income & self employed income
I have been retired for three years. All of my income was from retirement funds.
I just accepted a consulting project from my previous employer and set myself up as a sole proprietor LLC. We signed the contract in late April 2018, I started the project May 1 and they paid me an upfront payment that I deposited on May 8th. I will then receive three additional progress payments throughout the rest of 2018. Each remain payment will be for different amounts.
I used Turbo Tax to calculate my tax liability for this additional income. (Income Tax, SS & Medicare).
My question is this; how do you distribute the estimated payments for a project like this where I started on May 1 and the four payments will be for different amounts? Split the tax liability evenly, where the period 2 estimated payment is half the total liability? Or do I pay in proportion to the amount with will be paid to me in periods 2, 3 & 4?