How this calculator works
Both offers start with the same borrowed principal. Each can have a different nominal rate, compounding convention, amortization, upfront fees and extra payment. Compare the payment alongside total cost: a lower payment can come from a longer amortization and produce more interest. Fees are paid in cash and are not added to the balance. The annual table uses payment years, and all rates are held constant through repayment.
Formula
For each offer, i = (1 + r/c)^(c/f) - 1 and regular payment = P × i / (1 - (1 + i)^(-Nf/12)). Total offer cost = actual payments + upfront fees. Lifetime saving with B = A total cost - B total cost. Payment difference = B planned periodic payment - A planned periodic payment.
Worked example
At 0%, a $1,200 mortgage over 120 months costs $10 monthly, while a 60-month offer costs $20 monthly. With no fees they repay the same $1,200. If B charges a $100 upfront fee, its lifetime cost is $1,300 and its saving relative to A is negative $100.
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Frequently asked questions
Does the cheaper lifetime offer always suit me?
No. Monthly cash flow, your expected holding period, renewal risk and prepayment flexibility also matter.
Can I compare a Canadian and US convention?
Yes. Each offer has its own compounding selector. The tool does not convert currencies, so use one currency consistently.
Are early-sale balances considered?
The annual table shows remaining balances. The lifetime saving figure assumes each loan is held until fully repaid and does not discount cash flows.