Use Hesapstan's repo calculator to enter your principal, an assumed annual repo rate and the number of days, then see the gross return, the 15% withholding tax (stopaj), the net return and the amount at maturity in one place. Each return is also shown as a share of principal over the whole term. You choose the rate; the tool does not provide a live repo rate or an institution-specific quote.
How is repo return calculated?
Repo return is calculated by applying the assumed annual rate to the principal for the number of days divided by 365: Gross return = Principal × (Annual rate / 100) × (Days / 365). This tool uses simple interest, does not compound, and does not cap the term at one year; a 400-day input uses the same formula.
The calculation runs in this order (this is the derivation sequence, not the row order of the result table, where the amount at maturity is shown first):
- Gross return: the formula above, before tax.
- Withholding (stopaj): 15% of the gross return.
- Net return: gross return minus withholding.
- Amount at maturity: principal plus net return.
- Gross and net percentages: each return divided by principal. They describe the whole term you entered, not a yearly rate.
The annual rate in the calculation is the value you type. The rate your bank or broker actually offers that day may be different, so confirm the exact figure with the institution you deal with.
What is a repo, and how does it differ from a reverse repo?
A repo (repurchase agreement) is the sale of a security with a commitment to buy it back later on agreed terms. Borsa İstanbul, the Turkish exchange, describes repo and reverse repo transactions as investment instruments used by institutions that need funds and institutions that have funds to supply.
A reverse repo is the other side of the same transaction: the security is bought with a commitment to sell it back. Whether a trade is called a repo or a reverse repo depends on which party you look from. Banks in Turkey usually market this kind of short-term product to retail investors simply as “repo”, and collateral and contract details vary by institution. This tool has no separate reverse-repo mode.
Repo operations of the Central Bank of Turkey are monetary-policy operations that provide short-term liquidity to the market; they are not a product open to individual investors. A time deposit is also a different thing: it is money placed with a bank, not a securities transaction, and its legal structure and taxation differ from repo.
How should I read the result table?
The table shows the figure most people look for, the amount at maturity, at the top and then lists how the return is built up.
- Amount at maturity: the total you would expect when the term ends, which is principal plus net return.
- Gross return (before tax): the return before withholding, with its share of principal over the term in brackets.
- Withholding (15%): the tax deducted from the gross return.
- Net return: what remains after withholding, with its share of principal over the term in brackets.
- Principal, applied annual rate and term used: a check of what you entered.
- Note: a reminder that the result is an estimate and what it leaves out.
The percentage in brackets is not an annual rate. With a 36.5% annual rate over 10 days, the gross return is 1.00% of principal and the net return is 0.85%. To get the net return on an annual basis in this tool’s simple-interest logic, multiply the annual rate by 0.85 (36.5 × 0.85 ≈ 31.0).
What is the withholding tax on repo income in Turkey?
Withholding tax on repo income in Turkey is 15%. Section 18 of the 2026 Temporary Article 67 guide published by the Turkish Revenue Administration (GİB) states that income from repo transactions is subject to 15% withholding under paragraph (4) of Temporary Article 67 of the Income Tax Law, and that no annual tax return is filed for this income. The guide adds that it does not matter whether the income owner is a natural or legal person, or a full or limited taxpayer.
Deposit interest and investment fund income are separate income items. Their withholding rates may differ and can change over time, so do not apply this 15% to a deposit or a fund. If the law changes, the rate may change too; check GİB sources or a tax adviser for your own situation.
Example 1: ₺100,000 at 36.5% a year for 10 days
Suppose the principal is ₺100,000, the annual repo rate you assume is 36.5% and the term is 10 days. The tool returns:
- Gross return: 100,000 × 0.365 × (10 / 365) = ₺1,000.00 (1.00%).
- Withholding (15%): ₺150.00.
- Net return: ₺850.00 (0.85%).
- Amount at maturity: 100,000 + 850 = ₺100,850.00.
If you try the same inputs for 1 day, the gross return is ₺100.00, withholding ₺15.00 and net return ₺85.00. The net return is exactly 0.085% of principal, which the tool shows as 0.09% to two decimals.
Example 2: ₺42,500.75 at 12.75% a year for 30 days
Use a decimal point in the English version: type 42500.75 and 12.75. With these inputs the results are:
- Gross return: ₺445.38 (1.05%).
- Withholding (15%): ₺66.81.
- Net return: ₺378.58 (0.89%).
- Amount at maturity: ₺42,879.33.
The tool calculates with unrounded amounts (gross about 445.3845, withholding about 66.8077, net about 378.5768) and rounds to two decimals only for display. Subtracting the two rounded figures on screen can differ by 0.01; that is a rounding-order effect, not an error.
Common mistakes
- Confusing the annual rate with the period return: a 1.00% return over 10 days is not a 1% annual rate.
- Entering the wrong number of days: the tool divides the days you enter by 365; an institution may count days differently, and there is no value-date or business-day calendar here.
- Mixing up gross and net: when an institution quotes a single rate, ask whether it is before or after tax.
- Applying deposit or fund withholding to repo: these income items have separate rates.
- Rounding too early: rounding the gross return before computing the tax can create a one-cent difference.
- Forgetting commissions and institution fees: the result does not include them.
- Reading the result as an institution’s quote: it is an estimate based on your assumption.
What does this tool not calculate?
The tool produces a return estimate from three values you enter, using simple interest and a 15% withholding. It does not account for:
- A current or live repo rate: you enter the rate yourself.
- Commissions, account fees and institution-specific contract terms.
- The maturity date, value date or holiday calendar: you enter the number of days.
- Compound interest or reinvestment.
- Contractual differences between reverse repo, overnight repo or specific bank products.
- Tax rules for other income types or other countries.
You can also enter a 0% annual rate. That is a mathematical scenario in which return and tax are zero; it does not mean a repo offer exists at 0%.
The results rest on the assumptions you enter. They are not investment advice, an institution’s quote or a guaranteed return. Before dealing, get the rate, the tax treatment and the fees from the institution in writing.
Repo compared with deposits and other short-term instruments
When you compare repo with a deposit, start from the same principal and the same number of days, then work out each instrument’s net return under its own applicable withholding rate, fees and terms; the 15% used for repo does not carry over to a deposit. For deposits see the time deposit interest calculator, for short-term Turkish government or corporate bills the bono calculator, and for plain simple interest the interest calculator. These products do not share the same tax rules, so read each tool’s own explanation.
To see how much of the net return remains after inflation, use the real return calculator.
Frequently Asked Questions
How is repo return calculated?
Gross return = principal × (annual rate / 100) × (days / 365). Withholding is 15% of that amount, net return is the gross return minus withholding, and the amount at maturity is principal plus net return.
What is the withholding tax on repo in Turkey?
It is 15%. Section 18 of the Turkish Revenue Administration’s 2026 Temporary Article 67 guide says repo income is subject to 15% withholding under paragraph (4) of Temporary Article 67 of the Income Tax Law, and that no annual tax return is filed for it.
Is the percentage in the result an annual rate or a return over the term?
The percentage in brackets next to gross and net return is the return over the whole term as a share of principal. It is not an annual rate. For example, at a 36.5% annual rate the gross return over 10 days is 1.00% and the net return is 0.85%.
Is repo the same as a time deposit?
No. Repo is based on a security that is sold with a commitment to buy it back, while a time deposit is money placed with a bank. Their legal structure and taxation differ, so a withholding rate should not be carried from one to the other.
What is a reverse repo, and does this tool calculate it?
A reverse repo is the other side of a repo: a security is bought with a commitment to sell it back. This tool has no separate reverse-repo mode; it estimates a simple-interest return from the rate you enter.
Why is the term divided by 365, and is interest compounded?
The tool converts the annual rate to a daily amount on a 365-day year and uses simple interest; it does not compound. That is a product convention, not a legal requirement, so an institution that counts days differently may show a slightly different result.
Why can the net return differ by 0.01 from gross minus withholding on screen?
The tool calculates with unrounded amounts and rounds to two decimals only for display. Subtracting the rounded figures shown can differ by 0.01; this is not an error.
Does the tool show a current repo rate, and is the result a bank quote?
No. Repo rates change from day to day and between institutions. The tool uses only the hypothetical rate you enter and shows no live rate. The result is an estimate, not a quote or a guarantee.
Can I enter a 0% annual rate?
Yes. A 0% rate is a mathematical scenario: return, withholding and net return are zero and the amount at maturity equals the principal. It does not mean a current repo offer.
Are commissions and fees included?
No. The result includes only simple interest and the 15% withholding. Commissions, account fees and institution-specific terms are not included and can change the real net amount.