Nominal vs. Effective Interest Rates in Commercial Loans

The interest rate on a commercial loan quote is usually the nominal rate. What you actually pay over a year can be a little higher, depending on how often interest compounds and how the lender counts days. That difference is the gap between the nominal rate and the effective rate, and it is worth understanding before you compare loan offers.

Nominal vs. Effective: The Definitions

The nominal interest rate is the stated annual rate, before accounting for compounding. If a term sheet says 6%, that is the nominal rate.

The effective annual rate is what that nominal rate works out to over a full year once compounding is included. The formula is:

Effective annual rate = (1 + i / m)^m minus 1

Here i is the nominal annual rate as a decimal and m is the number of compounding periods per year. Monthly compounding means m = 12. Quarterly means m = 4.

The more often interest compounds, the higher the effective rate. When compounding happens once a year, the nominal and effective rates are the same.

A Worked Example

Here is an illustration with round numbers. These are example figures, not a quote or a current rate.

Take a nominal rate of 6.00% and run it through the formula at different compounding frequencies:

1. Annual (m = 1): (1 + 0.06)^1 minus 1 = 6.00%
2. Quarterly (m = 4): (1 + 0.06 / 4)^4 minus 1 = (1.015)^4 minus 1 = about 6.14%
3. Monthly (m = 12): (1 + 0.06 / 12)^12 minus 1 = (1.005)^12 minus 1 = about 6.17%
4. Daily (m = 365): about 6.18%

On a $1,000,000 balance, monthly compounding at a 6% nominal rate works out to about $61,678 of interest over a year if nothing is paid down, compared to $60,000 at simple annual interest. The difference is about $1,678. Not huge, but real, and it grows with the size of the loan.

One point that trips people up: when you make monthly payments, the interest is being paid as it accrues. The monthly payment on a standard amortizing loan is calculated from the nominal rate divided by 12, so the 6.17% figure is mostly useful for comparing offers on an equal basis, not for figuring your payment.

The Day Count Detail

Compounding is not the only thing that separates the quoted rate from what you pay. Many commercial loans calculate interest on an actual/360 basis. That means the lender divides the annual rate by 360 to get a daily rate, then charges it for the actual number of days in the month, which adds up to 365 days in a normal year.

The effect is simple to calculate. A 6.00% rate on actual/360 works out to 6.00% x 365 / 360 = about 6.08% over a year. On a $1,000,000 balance, that is about $60,833 of interest instead of $60,000. Residential mortgages usually do not work this way, so it surprises a lot of first time commercial borrowers.

The loan documents will spell out the day count method. It is worth reading that section, or asking the lender directly.

Why This Matters When Comparing Loans

Two term sheets can show the same rate and cost different amounts. Here is what I would look at side by side:

• Compounding and payment frequency: monthly is standard, but confirm it.
• Day count method: actual/360, 30/360, or actual/365.
• Fees and points: an origination fee raises the true cost of the money even though it does not change the stated rate.
• Amortization: a shorter schedule raises the payment even at the same rate.

The goal is to compare apples to apples. A slightly lower quoted rate with actual/360 interest and higher fees can cost more than a slightly higher rate without them.

What Local Borrowers Should Ask

Most of the commercial loans on smaller buildings in Coeur d’Alene, Post Falls, Hayden and Rathdrum come from regional and community banks and credit unions. Their loan documents are not all built the same way. In my experience, borrowers focus on the headline rate and skip the fine print on how interest is actually calculated.

If you are getting quotes from two or three local lenders, ask each one the same questions: how interest accrues, the day count basis, and the total fees. Then run the numbers on the same loan amount. It takes a few minutes and you will know which offer is really cheaper. Your lender and your CPA are the right people to confirm the details for your situation. This is general education, not financial advice.

Quick Recap

• The nominal rate is the stated annual rate.
• The effective rate includes compounding: (1 + i / m)^m minus 1.
• Actual/360 interest raises the real cost by a factor of 365 / 360.
• Compare loan offers on the same basis, including fees.

If you are lining up financing on a building and want help comparing term sheets, I am glad to walk through them with you. What are the lenders quoting you?