Amortization schedule
An amortization schedule shows you the year-by-year breakdown of a fixed (annuity) loan or mortgage payment — how much of each yearly amount is swallowed by interest, how much reduces the principal, and what debt remains. It is useful before signing, when comparing loan terms, or when weighing an early repayment. Enter the loan amount, the annual interest rate and the term in years; the calculator returns the monthly payment and the full amortization run. Amounts stay in CZK.
How the amortization schedule is calculated
The calculator uses annuity repayment: the monthly payment stays the same for the whole term, but its composition changes. Early on, most of the payment is interest on the high balance; near the end, principal repayment dominates. First the fixed monthly payment is computed, then each month the current balance is charged interest and the difference between payment and interest reduces the debt.
monthly payment = P × i ÷ (1 − (1 + i)^−n)
i = annual rate ÷ 12 ÷ 100 • n = years × 12
Where P is the borrowed amount (principal), i the monthly interest rate and n the total number of payments. Each month:
- Interest for the month = current balance × i.
- Principal repaid = monthly payment − interest.
- New balance = old balance − principal repaid.
The table then sums twelve months into each year and shows the annual interest, annual principal and the balance at year end.
Step-by-step worked example
Take a mortgage of 3,000,000 CZK at 5% p.a. over 30 years (360 payments). Monthly rate i = 5 ÷ 12 ÷ 100 = 0.4167%. The exact monthly payment is 16,104.66 CZK, shown rounded to 16,105 CZK; the total uses the unrounded value.
| Step | Item | Calculation | Amount |
|---|---|---|---|
| 1 | Monthly payment | 3,000,000 × 0.004167 ÷ (1 − 1.004167⁻³⁶⁰) | 16,105 CZK |
| 2 | Interest in month 1 | 3,000,000 × 0.004167 | 12,500 CZK |
| 3 | Principal in month 1 | 16,105 − 12,500 | 3,605 CZK |
| 4 | Interest in year 1 | sum of 12 months | 148,995 CZK |
| 5 | Principal in year 1 | sum of 12 months | 44,261 CZK |
| 6 | Balance after year 1 | 3,000,000 − 44,261 | 2,955,739 CZK |
| 7 | Total paid over 30 years | 16,104.66 × 360 | 5,797,674 CZK (interest 2,797,674 CZK) |
Over thirty years you pay almost another 2.8 million CZK in interest on a 3-million loan. In the first year the overwhelming part of each payment is interest and the debt drops by only 44,261 CZK — which is why early extra repayments pay off the most.
What affects the result
- Interest rate — even a small difference in percentage points means hundreds of thousands of crowns of extra interest on a long mortgage.
- Term — a longer term lowers the monthly payment but sharply raises the total interest paid.
- Loan amount (principal) — enters the payment linearly; twice the loan means twice the payment at the same rate.
- Extra repayments — reducing principal (not included here) speeds up amortization and saves interest, most of all at the start.
- Rate type — the calculator assumes a fixed rate; after a fixation period ends the payment may change.
When the schedule helps and what to watch for
Use the breakdown to compare offers, plan a budget, or consider refinancing or an early repayment. The calculation is indicative and assumes the same rate throughout. It excludes loan administration fees, payment-protection insurance, property valuation, taxes and any change of payment after the fixation ends. The binding amortization schedule and APR always appear in the contract from your specific bank — follow that when signing.
⚠️ Indicative calculation, rates current for 2026. Not a substitute for an accountant or tax advisor — verify important decisions with the Czech Financial Administration.
FAQ
What is the monthly payment on a 3,000,000 CZK loan at 5% over 30 years?
About 16,105 CZK per month (exactly 16,104.66 CZK). Over the full 30 years (360 payments) you pay roughly 5,797,674 CZK, of which about 2,797,674 CZK is interest.
What is an annuity payment?
A payment that stays the same throughout the term. Only its composition changes — interest dominates at the start, principal repayment at the end.
Why do I pay almost only interest at the beginning?
Interest is charged on the outstanding balance, which is highest at the start. So in the first years interest eats most of the payment and the principal falls slowly.
How can I shorten the term and save on interest?
The most effective way is an extra repayment as early as possible or a higher regular payment. Cutting the principal early saves the most interest. This calculator does not model extra repayments.
Does the calculation include fees and insurance?
No. It computes only interest and principal repayment. Account fees, insurance, valuation and other costs are reflected separately in the APR in the bank's contract.
What happens after the fixation period ends?
The calculator assumes one fixed rate for the whole term. In reality the bank offers a new rate after fixation and the monthly payment and remaining schedule are recalculated.
How does a mortgage schedule differ from a consumer-loan one?
The annuity principle is identical. Mortgages usually have a lower rate and longer term, consumer loans a higher rate and shorter term, so the interest-to-principal ratio differs.
Is the calculated schedule binding?
No, it is indicative. The binding schedule and APR come from the bank in the loan contract; small differences arise from rounding and the interest-charging method.
Sources & legislation
📅 Last updated: 11 July 2026