Online / Excel Tax Calculator

I am looking for a calculator to help me calculate what I need to set aside for tax on what I earn each month, I am self-employed and my monthly rate stays the same for the most part, but there can be some variations. I just want something where I can input my monthly earning figure, and it simply tells me what I need to put aside that month out of what I earn. Thank you!

Hi,

Our Self Assessment ready reckoner tool can help with this:

Budget for your Self Assessment tax bill if you're self-employed

Thank you.