Why not just use one worldwide calculator? Because the differences are not cosmetic. A Canadian mortgage at a given rate costs less per month than the same rate in the US, because Canadian lenders quote rates compounded semi-annually. A buyer in Toronto pays land transfer tax twice — once to Ontario, once to the city — while a buyer in Alberta pays almost none. A first home in Sydney can be stamp-duty-free below a threshold that does not exist in Melbourne. Each calculator on this page models its own jurisdiction's formula, insurance, taxes and first-buyer reliefs, with the rates and bands shown on the page and dated, so you can see exactly what went into the number.
All figures are estimates for planning and education. Tax bands and program thresholds change — sometimes every budget — so confirm the final numbers with your lender, broker or the official revenue authority linked in each calculator's notes before you commit.