CPP/QPP, EI, QPIP, federal and provincial tax — calculated by the exact same engine behind every real ApexPayGo payroll run, for all 13 provinces and territories.
This tool uses calculate_deductions() — the same function ApexPayGo uses to run real payroll — so the numbers here match what a real paycheque would show. It does not track year-to-date history, so CPP/EI are shown as if this were the first payment of the year; a real employee partway through the year, already near the annual CPP/EI maximum, would see slightly less withheld.