underwriting and offer workspaces · Intermediate

Interest accrual convention comparator

Reconcile interest under explicit day-count conventions. Includes calendar-based interest comparison with visible formulas.

Commercial Debt Advisory EditorialModel 1.0.0Reviewed by Jason Taken · 2026-10-21T19:41:22.818Z

Your assumptions

Illustrative starting values. Replace them with your own evidence. Inputs stay in this browser.

Your scenario, explained

Results

Calculation assumptions

Version 1.0.0 · Educational scenario, subject to the stated assumptions.

How this calculation works

Method and assumptions

Simple interest equals principal × annual rate × contractual day-count fraction. Actual/Actual uses the selected year denominator; split periods spanning years before using this comparison.

Worked example

For $3 million outstanding at 6.5%, 31 actual accrual days on Actual/360 produce $16,791.67 of simple interest. An entered 30-day 30/360 period produces $16,250.00. The $541.67 difference comes from day-count conventions, not a change in the stated annual rate.

Before using the result

Know the boundaries

Educational scenario, not a quote, commitment, approval, appraisal or payoff statement.
Defaults and thresholds are editable illustrations; the executed documents and lender underwriting control.
Enter the correct 30/360 days from the note; this tool does not resolve different 30/360 date rules or cross-year Actual/Actual periods. No compounding.

Calculation standards →