Help: Loans / Solutions
A complete financial loan calculator — it can calculate the installment, the principal, the number of installments, or the interest rate (whichever of the four you don't know), with a full repayment schedule and optional "special terms" on specific installments.
Before you start, it helps to know that there are different ways ("amortization methods") a loan can be repaid:
- Annuity: a fixed installment throughout the term, interest decreases and the principal portion increases over time — the most common way for mortgage/consumer loans. The application supports this as the default.
- Constant principal: a fixed principal portion every installment, a decreasing total installment (the 1st is the largest) — the application supports this as a second option in the "Amortization method" field (Step 1).
- Bullet / balloon: you pay only interest throughout the term and the principal as a lump sum at the end — you can simulate this with Special Terms ("Interest only" on all installments except the last) or with the "Remaining amount" field.
- Floating / variable rate: this isn't a separate amortization method but a change in the interest rate itself during the term — covered by "Rate Change" (Step 4), and works with both amortization methods above.
The method is selected in the "Amortization method" field in Step 1 below.
Fill in the loan details
- Principal (€)
- The loan amount.
- Amortization method
- Annuity (fixed installment): the installment is the same throughout the term; interest decreases and the principal portion increases over time. The usual choice. Constant principal (fixed principal): the principal portion is the same every installment, so the total installment decreases gradually (the 1st is the largest). The "Installment" field then represents the 1st installment.
- Annual Interest Rate (%)
- The annual nominal interest rate.
- Frequency
- How often you pay an installment: monthly, quarterly, semi-annually or annually.
- Total installments
- The total number of installments. With the "Installments"/"Years" buttons next to the field, you can toggle whether you enter the number in installments or in years (the application converts between them automatically).
- Loan type
- Ordinary (arrears): the installment is paid at the end of each period (the usual case). Advance (in advance): the installment is paid at the beginning of each period.
- 1st installment date
- The date the first installment is paid.
- Remaining amount (€)
- If there will be an outstanding balance at the end of the period (e.g. a balloon payment), enter it here. Usually 0.
- Installment (€)
- If you already know the installment amount, enter it. Leave it as 0 to have the application calculate it.
- Calculate:
- Which of the four basic quantities (Installment, Principal, Number of installments, or Interest rate) you want the application to calculate — you must already know and have entered the other three.
View the summary and repayment schedule
| Installment (base) | 316,38 € |
| Principal | 50.000,00 € |
| Total | 75.931,20 € |
| Interest | 25.931,20 € |
Below the summary, the detailed repayment schedule appears — one row per installment, with initial balance, interest rate, installment, interest, principal repaid, and new balance. By clicking the green Excel button (top right of the table) you download the entire table as an Excel file to keep or edit it — with the same color coding as on screen.
The "Interest Rate" column shows the annual interest rate that applied to that specific installment and always has blue text, so it's easy to distinguish from the other columns. If you have defined one or more Rate Changes (see Step 4 below), the exact installment from which each new rate starts is specially marked, with a bold blue background, white text and an icon — this way you can spot at a glance exactly where the rate changes during the life of the loan, without having to search row by row.
Προαιρετικό: Ειδικοί Όροι Δόσεων
The "Installment Special Terms" allow you to specify that one or more specific installments will differ from the rest — that is, the interest rate or the calculation method for the whole loan doesn't change, only the amount of specific installments that you choose. It's used to simulate real agreements or situations such as:
- A grace period at the start of the loan (e.g. for the first 6 months you pay only interest, no principal).
- A temporary payment suspension (e.g. due to financial hardship, an arrangement with the bank).
- An extra ("13th") installment in a specific month each year, or a reduced installment during the summer months.
- Any other special arrangement that concerns individual installments and not the loan's interest rate.
The bottom of the page contains the "Installment Special Terms" section where you define them:
| ☑ | 3 | 04/11/26 |
| ☑ | 4 | 04/12/26 |
| ☐ | 5 | 04/01/27 |
| # | Date | |
|---|---|---|
| 12 | 04/07/27 | ✕ |
- Select installments: manually check the installments you want from the list (or click "All"/"None").
- or Month frequency: alternatively, select one or more months (01-12) — ALL installments that fall in that month, in every year, will be selected automatically (e.g. selecting "12" applies the same special term to every December).
-
Special installment type:
- Interest only: you pay only the interest for that installment, without repaying any principal (grace period).
- Zero installment: you pay nothing for that installment (payment suspension).
- or Amount: you set a fixed amount in euros for that installment.
- or Percentage: the installment becomes a percentage % of the regular installment.
- or Increment: an extra amount is added on top of the regular installment (e.g. an extra installment in December).
After selecting installments/months and type, click "Apply" — they are added to the list on the right, without any calculation happening yet. You can repeat this step for as many special terms as you want to add.
When you're done, click the green "Update installments" button — only then is the repayment schedule recalculated with all the special terms together, and the special installments are shown with a yellow background and a star. You can remove a term individually (✕ next to it) or all of them together with "Delete special installments" — again, click "Update installments" for the change to show in the table.
- "Zero installment" / "Fixed amount": the principal that is "lost" (or added) at that installment is automatically redistributed among the remaining regular installments, so the loan continues to be repaid over the same total number of installments. If the installment doesn't cover the interest (e.g. a zero installment), the unpaid interest is capitalized into the balance.
- "% of PMT": the percentage is applied to the principal portion of the "regular" installment at that point — not to a fixed reference value, since the principal portion may have already changed due to other special terms.
- "Increment": added on top of the regular principal portion of that installment.
Προαιρετικό: Αλλαγή Επιτοκίου
"Rate Change" is different from Special Terms: here it's not the amount of individual installments that changes, but the loan's annual interest rate itself from a certain point onward — and all subsequent installments (until the next change or the end of the loan) are recalculated with the new rate. Use it to simulate real scenarios such as:
- The end of a fixed-rate period and transition to a floating rate (e.g. a mortgage with the first 5 years fixed, then floating).
- An expected adjustment of a reference rate (e.g. Euribor) that will affect your floating rate.
- Renegotiation/refinancing of the loan with a new interest rate from a specific date.
- Comparing "what if" scenarios — e.g. how much your installment will increase if the rate rises by 1% in two years.
Further down, after the "Installment Special Terms", there is the separate "Rate Change" section where you define them:
| Installment | Date | New Interest Rate (%) | |
|---|---|---|---|
| #13 | 01/01/27 | 6,5000% | ✕ |
From the list, select the installment from which the new rate will apply, enter the new annual interest rate and click "Add" — it is added to the list on the right, without any calculation happening yet. You can add more than one rate change at different installments (they will apply sequentially, each until the next one).
When you're done, click the green "Update installments" (it's also here, in the "Rate Change" section, so you can update the table even if you haven't defined any Special Term) — only then is the repayment schedule recalculated: from each rate-change installment onward, the installment is automatically recalculated with the new rate so that the loan continues to be repaid over the same total number of installments, until the next rate change (if any) or until the end of the loan. You can remove a change individually (✕ next to it) or all of them together with "Delete all".
Optional: Export / Import Scenario
At the top right of the repayment table, besides the Excel button (full repayment table, read-only), there are two more buttons to save and reload the parameters of a loan scenario:
- Export Scenario: downloads a small, separate Excel file with just the loan's data (principal, interest rate, installments, special terms, rate changes, etc.) — not the detailed table. Fields with specific choices (loan type, special term type, what the app should calculate) appear with a yellow background and a dropdown list inside Excel, so you can't type an invalid value. The Special Terms and Rate Changes tables always have at least 10 and 5 ready rows respectively, formatted and ready to fill in.
- Import Scenario: opens a window where you select such an Excel file (either as you downloaded it or after editing it) — the page reloads with all the data and the repayment table recalculated from scratch with the new values.
Useful for keeping several different loan scenarios in separate files, sharing them, editing them offline, and bringing them back into the app later. When filling in new rows in the Special Terms/Rate Changes tables, write them sequentially, without leaving blank rows in between.