Rule of thumb for NIC?

[hashman]

Does anyone have a quick and easy rule of thumb for checking whether too much NIC has been paid?

I used to work on the basis that if I had paid the maximum class 1 on my salary then I had no class 2 or 4 liability on my self employed earnings. Since the extra 1% came in this is of course no longer true. I have read that there is a NINE STEP (!) process to calculate the maximum.