The calculators here compare fixed-rate and adjustable-rate mortgages in terms of the future value of all costs in dollars.

Mortgage comparison calculators are designed to help you choose between FRMs and ARMs. For background reading, I suggest Choosing Between Fixed and Adjustable Rate Mortgages. The question is the same one covered by Mortgage Interest Calculators, the difference being in the methodology. The calculators here use future value analysis while the others use interest cost. The two approaches are equally valid and should give the same answer 99% of the time. The technical definition   of future value can be found in Mortgage Formulas.

Future Value Comparison Calculator: FRM Versus ARM With No Negative Amortization.
For borrowers trying to decide between an ARM without negative amortization and an FRM based on the lowest cost over a specified future period.

Future Value Comparison Calculator: FRM Versus ARM With Negative Amortization.
For borrowers trying to decide between an ARM with negative amortization and an FRM based on the lowest cost over a specified future period.

Future Value Comparison Calculator: Two Fixed-Rate Mortgages.
For borrowers trying to decide between two FRMs based on the lowest total cost over a specified future period.