Interest Rate (Zinssatz)

The cost of borrowing money

3 min readUpdated December 2024

The interest rate (Zinssatz) is the annual cost of borrowing money for your mortgage. In Germany, rates can be locked for 10-30 years, making them a crucial component of long-term investment planning.

Current Market Context

As of 2024, German mortgage rates for investment properties typically range:

  • 10-year fixed: 3.8% - 4.5%
  • 15-year fixed: 4.2% - 4.8%
  • 20-year fixed: 4.5% - 5.2%

Rates depend on loan-to-value ratio, income, creditworthiness, and property type

How Interest Rate Affects Your Returns

€450,000 Property with 90% Financing (€405,000 loan):

At 3.5% Interest Rate:

  • • Annual interest: €14,175
  • • Monthly payment (2% amortization): €1,856
  • • Tax savings (42% bracket): €5,954
  • • Net interest cost: €8,221/year

At 5.0% Interest Rate:

  • • Annual interest: €20,250
  • • Monthly payment (2% amortization): €2,362
  • • Tax savings (42% bracket): €8,505
  • • Net interest cost: €11,745/year

A 1.5% rate difference = €3,524 more annual cost (even after tax deduction)

Fixed Rate Periods (Zinsbindung)

German mortgages offer uniquely long fixed-rate periods:

  • 5-10 years: Lower rates but refinancing risk
  • 15-20 years: Balance of rate and security (most popular)
  • 25-30 years: Maximum security but higher rates

Interest Deductibility: The Silver Lining

Unlike personal loans, all mortgage interest on investment properties is tax-deductible. This means your effective interest rate is 42% lower if you're in the top bracket. A 4.5% mortgage effectively costs you 2.6% after taxes.

When to Lock in Rates

  • Rates are low: Lock for 20+ years to protect against future increases
  • Rates are high: Shorter lock (10 years) with option to refinance when rates drop
  • For rentals: Longer locks provide cashflow predictability

Model different interest rate scenarios