There are various reasons why you may see calculations different than expected. Here are some of the common reasons for discrepancies. :

Common Errors:

Error within the cell formula - whether you are pulling in the wrong cell or have the formula not accounting for something, this tends to be quite a common room for error in loan calculation when using spreadsheets
Counting the wrong number of days in a period (for example not taking into account 29 days of February on a leap year or an incorrect calculation of the difference between 2 dates
Using a different value for calculation - ensure that your spreadsheet is using the correct values for interest rates, outstanding principal, etc.
Ensure that your previous transactions are correct - missing a previous payment or putting the wrong amount on a previous principal/compounding repayment will cause differences along the schedule

Differences in terms settings on HC:

Days settings - please ensure that you are using the correct days settings whether it's 365/actual, 360/30, or another setting. These tend to cause differences that accumulate over time
Index rate settings - if you index your loan, please ensure that the index rate settings and determination frequency are set up correctly
Compounding settings - compounding frequency tends to cause differences in calculations if set up differently

Frequently Asked Questions