Three inputs to gross interest
A simple term-deposit calculation uses principal, annual gross rate and days. On a 365-day basis, gross income equals principal times annual rate times days divided by 365. For TRY100,000 at 45% for 32 days, the result is TRY3,945.21. A contract using a 360-day basis, compound renewal or a non-interest-bearing portion will produce a different result. Do not treat the advertised annual rate as the percentage paid at the end of a short term.
How to calculate net income
Net income equals gross interest less the applicable tax deduction and any separately charged fees. The 15% in the table is an illustrative deduction from income, not a current tax rate. In the 45% example, 15% of TRY3,945.21 is TRY591.78, leaving TRY3,353.42 and an ending balance of TRY103,353.42. The deduction is applied to income, not principal. Currency, term, opening date and customer status can change the actual conditions.
| Annual gross rate | Gross income (365-day basis) | After illustrative 15% gain deduction |
|---|---|---|
| 40% | TRY3,506.85 | TRY2,980.82 |
| 45% | TRY3,945.21 | TRY3,353.42 |
| 50% | TRY4,383.56 | TRY3,726.03 |
The advertised rate is not necessarily your quote
A promotional rate may require a new-customer status, balance range, mobile application, salary transfer or another product. Some accounts keep part of the balance interest-free, so the headline rate does not apply to the full principal. Read minimums, caps and early-withdrawal terms. A bank may quote different rates for different balances and terms. Base the comparison on the maturity payment calculated for your balance, not the campaign headline.
What happens on early withdrawal?
Early withdrawal may pay no interest, a lower rate or allow partial access depending on the product. Consider when cash may be needed, not only the highest rate. An automatic renewal need not use the initial rate. If maturity falls on a weekend or holiday, value and payment dates follow the bank’s terms. A shorter term can be more useful for a depositor with near-term liquidity needs even if its headline rate is lower.
Real outcome and comparison discipline
A larger balance does not guarantee greater purchasing power. Compare the net term return with price changes over the same period using real return equals (1 + net return) divided by (1 + inflation) minus one. Do not compare a one-month deposit return directly with annual inflation. Across banks, align principal, days, day-count basis, income deduction, non-interest-bearing balance and net maturity proceeds. TCMB average deposit rates provide market context, not a personal bank quote.
Related market pages and tools
Sources and further reading
Numerical examples are illustrative scenarios, not company data, bank offers or current tax rates.
This content is general information and financial education. It is not personalized investment advice or a recommendation to buy or sell.