The Ultimate Guide to Mortgage Amortization: French vs German vs American Systems

Understanding how your mortgage works is just as important as finding the lowest interest rate. The way your loan is amortized—paid off over time—can significantly impact your monthly payments and the total interest you pay.

In this guide, we will explore the three most common amortization systems used globally: the French System, the German System, and the American System.

What is Loan Amortization?

Amortization is the process of spreading out a loan into a series of fixed payments over time. You'll be paying off the loan's interest and principal in different amounts each month, depending on the system used.

1. The French System (Constant Payment)

The French Amortization System is the most widely used method in many parts of the world, including most of Europe and for standard mortgages in the US (often called a fixed-rate mortgage).

Key Characteristics:

• Monthly Payment: Constant. You pay the exact same amount every month.
• Interest vs. Principal: In the beginning, a large portion of your payment goes toward interest. As the principal balance decreases, the interest portion shrinks, and more of your payment goes toward the principal.

Pros and Cons:

• Pros: Predictability. You know exactly what you need to budget for every month.
• Cons: You build equity slowly in the early years.

2. The German System (Constant Amortization)

The German Amortization System works differently. Instead of a fixed monthly payment, the amount of principal you pay off each month is fixed.

Key Characteristics:

• Monthly Payment: Variable (Decreasing). Your first payment is the highest, and it goes down every month.
• Interest vs. Principal: You pay a fixed amount of principal plus the interest on the remaining balance. Since the balance drops every month, the interest drops, and so does your total payment.

Pros and Cons:

• Pros: You pay less total interest over the life of the loan compared to the French system. You build equity faster.
• Cons: The initial payments are significantly higher, which can be a burden for first-time buyers.

3. The American System (Interest Only)

The American System, often referred to as an "Interest-Only" loan in the context of amortization, is quite distinct.

Key Characteristics:

• Monthly Payment: Very low (Interest only).
• Interest vs. Principal: You only pay the interest due each month. You pay zero principal during the term.
• Balloon Payment: At the end of the loan term, you must pay back the entire original loan amount in one lump sum.

Pros and Cons:

• Pros: extremely low monthly payments during the term. Good for investors who plan to sell the property before the term ends or who have irregular cash flow.
• Cons: Extremely risky. You build no equity. You face a massive payment at the end.

Which System is Right for You?

• Choose French if you need stability and a consistent budget.
• Choose German if you can afford higher initial payments and want to save on total interest.
• Choose American only if you are an experienced investor with a clear exit strategy.

No matter which system you consider, running the numbers is essential.