Martin Lewis has explained that the magic number is £35,000 to “break even”.
He said: "If you’re under that [amount], this is a gain, if you’re over that [amount], then the two measures are a loss for you.
"Effectively the way it works on earnings is from over around £9,600, all the way up to around £35,000, you will either not pay any more, or lower down [the pay scale], will pay less National Insurance than currently.”
He added: "If you earn £35,000 or more then the 1.25 percentage point increase outweighs the change in the starting threshold, so you will pay more National Insurance."