The 1.25 per cent point cut to National Insurance rates for employees and employers took effect across the UK on Sunday (6 November).
The tax cut was announced by the government on 22 September, as part of the reversal of the Health and Social Care Levy. It will reduce tax for 920,000 businesses by nearly £10,000 on average next year as they will no longer pay a higher level of employer National Insurance.
The move to reverse April National Insurance increase follows the rise in National Insurance thresholds in July.
As a result of both measures, almost 30 million people will be £500 better off, on average, next year, the Treasury said.
Working people across the UK will begin receiving the tax cut in their payslips this month, with all expected to have started receiving it by February.