How the numbers are worked out
Your NHS pension is taken before tax (a "net pay arrangement"), so it reduces your income tax as well as your pay. National Insurance is charged at 8% between £12,570 and £50,270 a year and 2% above that. Income tax uses the standard 1257L tax code with England, Wales and Northern Ireland rates. Scottish taxpayers pay slightly different rates.
What isn't included
Unsocial hours enhancements, overtime, high cost area supplements (London weighting), salary sacrifice schemes and union subscriptions all change your final figure. Check your payslip for the exact deductions.