Mortgage Comparison 2026: Calculate Rates and Interest

Buying a property today means committing financially for decades. With a typical loan amount of 350,000 euros and a term of 25 years, interest payments quickly add up to a six-figure sum. This is exactly where a careful comparison separates smart buyers from those who end up paying significantly more for the same property. Even an interest rate difference of just 0.2 percentage points means a difference of around 14,000 euros over the entire term of the loan for this amount.

Unlike consumer loans, mortgage construction financing (Baufinanzierung) is a long-term strategic project. Fixed interest periods, repayment rates, unscheduled repayment rights, and the clever integration of state subsidies (such as KfW loans) must be precisely coordinated. This guide explains the key adjustment options and uses concrete calculation examples to show what really matters when comparing offers.

What Are the Components of Construction Financing?

A solid property financing plan rests on four pillars. Each one affects how high your monthly burden will be and how quickly you will become debt-free.

What Is the Difference Between Nominal Interest (Sollzins) and Effective Interest (Effektivzins)?

The nominal interest rate (Sollzins) describes the pure interest rate for the borrowed money. The effective interest rate (Effektivzins), on the other hand, includes all incidental costs of the financing, such as processing or brokerage fees. For comparing offers, the effective interest rate is the only rate that matters.

How Long Should the Fixed Interest Period (Sollzinsbindung) Be?

The fixed interest period (Sollzinsbindung) determines how many years your interest rate remains unchanged. Usual periods are 10, 15, or 20 years. A longer fixed period offers planning security but costs a rate premium. However, according to § 489 BGB (German Civil Code), you always have the right to cancel a loan after ten years with a six-month notice period free of charge.

How High Should the Initial Repayment Rate (anfängliche Tilgung) Be?

The repayment (Tilgung) is the portion with which you reduce the remaining debt. In low-interest phases, the initial repayment rate should be at least two to three percent to ensure rapid debt reduction. With each installment, the interest portion decreases while the repayment portion increases.

What Role Do Unscheduled Repayments (Sondertilgungen) Play?

Unscheduled repayment rights (Sondertilgungsrechte) allow you to make unscheduled payments to reduce the remaining debt faster. Many banks grant up to five percent unscheduled repayment per year free of charge. Use this option to put unplanned income or bonus payments directly into your home equity.

How Does the Repayment Rate Affect the Loan Term?

A higher repayment rate increases your monthly installment but shortens the term of the loan dramatically and significantly lowers the total interest burden. The following table shows a comparison for a loan of 300,000 euros at an interest rate of 3.5 percent:

Which Incidental Purchase Costs (Kaufnebenkosten) Must Be Considered?

When purchasing a property, substantial incidental costs arise, which usually must be financed from your own capital (Eigenkapital). These costs are structured as follows:

What State Subsidies Can Be Used?

The KfW bank supports property purchase with low-interest loans and subsidies. The most important programs are:

• KfW-Wohneigentumsprogramm (124): Promotes the purchase or construction of owner-occupied housing with up to 100,000 euros.
• Klimafreundlicher Neubau (297/298): Low-interest loans for energy-efficient new builds.
• Wohneigentum für Familien (300): Supports lower-income families with children in building or purchasing a home.

What Mistakes Should You Avoid in Construction Financing?

1. Too tight budget planning: Always plan a financial reserve for unforeseen expenses.
2. Lack of equity capital: A higher equity ratio reduces the bank's risk and leads to significantly better conditions.
3. Neglecting follow-up financing (Anschlussfinanzierung): When the fixed rate period ends, you need to refinance the remaining debt. Plan for this risk early.
4. Requesting offers only from your main bank: Always get multiple quotes to secure the best rates.

Sources: KfW Bank, Deutsche Bundesbank, German Civil Code § 489 BGB.

Plan ahead: Calculate your monthly disposable income with the Gross-Net Calculator to determine the optimal monthly installment for your financing.