Net pay is the money you are actually paid. Start from gross pay, take off income tax, take off the employee share of social contributions, then take off anything else deducted through payroll, such as a pension or a student loan repayment. What remains is the figure that budgets and rent are paid from.
A worked case shows the scale. A single American on $75,000 under 2026 federal rules subtracts the $16,100 standard deduction set by the IRS, pays $7,670 of income tax on the remaining $58,900, and pays $5,737.50 of Social Security and Medicare at the rates in IRS Topic 751. Net pay is $61,592.50, about 82% of the gross figure, or $5,132.71 a month. State income tax would come off on top.
Net pay is not the same as net income in accounting, where it means profit after costs, and it is not what the job costs your employer. Employer contributions, such as the matching 7.65% in the US, are paid on top of gross pay and never pass through your hands. A payslip can also show deductions you chose, like a season ticket loan, so your net figure can sit below what the tax rules alone would give.
Because rounding and timing differ between payroll systems, a single payslip can be a little off one twelfth of the annual figure. The take-home pay calculator works out the year first and then spreads it across monthly, two weekly or weekly pay dates, in each of the fifteen countries it covers.