Payment certainty
A fixed rate usually provides a known interest rate for the term. It can make budgeting easier, but the cost of ending the mortgage early needs attention.
Rate movement
A variable rate can move with the lender’s prime rate. Whether the payment changes or the interest portion changes depends on the mortgage product.
A useful comparison
Ask what a higher rate would do to your cash flow and what a sale would mean for a penalty. Predicting the next rate decision is only a small part of choosing a suitable mortgage.