The formulas used in this calculator are all valid algebraically, but you should consider them as just approximations financially.

For example, you might compute a payment amount of $123.4567. Obviously it's not possible to make a payment of .67 cents, so you'll be paying either $123.45 or $123.46 a month. This affects the next month's balance and it will be different from what is computed by the formula. Over time, these differences may either grow or cancel themselves out.

In a real loan situation you may see minor discrepancies from the results of the calculations here.

Beyond rounding errors, you may also find differences because some financial institutions apply traditional or creative accounting techniques such as the "rule of 78" or the 360/365 rule. Your best protection is to read all documents carefully.