You're paying two separate income taxes on the same paycheque, not one blended Canadian rate. Federal tax and Ontario tax are each calculated on your full taxable income using their own five-bracket schedules, then added together, and each level applies its own Basic Personal Amount as a credit that shrinks what you owe rather than a chunk of income you don't pay tax on at all.
The Ontario Surtax and the Ontario Health Premium are where a lot of the confusion lives, because neither one is a tax on your income directly. The Surtax is a tax on your Ontario tax payable: once that figure crosses $5,818 you pay 20% extra on the amount over it, and a second 36% layer kicks in above $7,307, stacking to an effective 56% marginal rate on Ontario tax above that point. The Health Premium is a separate step function based on taxable income, ramping up through several plateaus to a $900 annual cap, and it isn't indexed, so it's stayed the same dollar amounts since 2004.
CPP2 is the newest piece of this puzzle. Once your income clears the Year's Maximum Pensionable Earnings ($74,600 for 2026), a second 4.00% CPP2 contribution kicks in on top of base CPP, up to a higher ceiling. Anyone earning above roughly $75,000 sees both CPP and CPP2 on their pay stub, alongside EI, which is capped separately at its own earnings ceiling.