The tax cut represents a £6bn cut to National Insurance effective from 6 July and is worth an average £175 a year to taxpayers and will go some way towards offsetting the 1.5% increase introduced through the social care levy, which came into effect on 6 April.

The online checker will use salary information for employees who are paid through PAYE system, giving personalised estimates of how much they could save because of the government’s changes. All you have to do is enter your current salary before tax and it calculates the estimated saving depending on earnings.

The cut, which will see the point at which people start paying National Insurance rise to £12,570, is worth up to £330 and seven in 10 workers will pay less National Insurance even after accounting for the health and social care levy, the Treasury said.