Typical Use Cases

Short-term loans, credit card overdrafts, and current account wealth management—you've likely encountered these three scenarios.

Daily Interest on Short-Term Loans: Borrowed money from a friend or online lender with daily accrual interest? Want to know how much interest you pay daily and how much in total by maturity? Simply calculate the daily interest rate from the annual rate and multiply by the number of days.
Credit Card Overdraft Interest: Credit card not fully paid off? The bank charges compound interest daily. First calculate the daily interest rate, then accumulate day by day (this tool calculates the simple interest portion; compound interest is more complex and can be used as a reference).
Current Account Wealth Management Returns Estimation: Money market funds and similar products (like Alipay's Yu'ebao) typically announce annualized 7-day returns; converting to daily interest rate helps you estimate daily deposits.

Principles and Formulas

There are two core formulas for daily interest rate:

Daily Interest Rate (%) = Annual Interest Rate (%) ÷ 360
Daily Interest (¥) = Principal (¥) × Daily Interest Rate (%) × Number of Days

Why divide by 360? This is the standard practice of domestic banks and most financial institutions (a year is 360 days, a month is 30 days). If you calculate using 365 days, the result will be slightly different, but 360 is more common in practice. Our calculator defaults to 360 days, but you can also switch to 365 days.

Note: This tool calculates simple interest only and does not handle compound interest. If you need daily compound interest calculations (such as credit card overdrafts or certain online loans), the results will be slightly different, but can serve as an approximate reference.

Complete Examples

Main Example: You borrowed ¥100,000 at an annual interest rate of 12% and paid it back in 30 days.

Step 1: Calculate Daily Interest Rate Enter "12" in the annual interest rate field and click "Calculate"; the daily interest rate will show as 0.03333% (i.e., 12 ÷ 360).
Step 2: Calculate Daily Interest Enter "100000" for the principal; the daily interest rate is auto-populated; enter "30" for days and click Calculate.
Result: Daily interest is ¥33.33; total interest for 30 days is ¥1,000 (33.33 × 30 ≈ 999.9, rounded to 1,000).
Explanation: You pay ¥33.33 in interest daily; at maturity, you owe ¥101,000 principal and interest combined. For a 12% annualized loan used for 30 days, the total cost is ¥1,000.

Comparison Example (Different Rates): Same ¥100,000 borrowed, 30 days, but with an annual interest rate of 5%.

Daily Interest Rate: 5 ÷ 360 = 0.01389%
Daily Interest: 100,000 × 0.01389% = ¥13.89
Total Interest: 13.89 × 30 = ¥416.70
Conclusion: The lower the interest rate, the lower the daily interest. You can quickly compare different rates by switching the annual interest rate in our calculator.

Another Example (Different Duration): Annual interest rate 12%, principal ¥100,000, loan term 10 days.

Daily interest rate remains 0.03333%; total interest = 33.33 × 10 = ¥333.30. The shorter the duration, the lower the interest.

Common Misuses and Pitfalls

Using 365 Days Instead of 360: Most banks and small loan companies use 360 days; if you calculate using 365 days, your daily interest rate will be slightly lower (e.g., 12% ÷ 365 ≈ 0.03288% vs 0.03333%). Although the difference is small per transaction, it can accumulate to errors.
Confusing Annual Rate with Monthly Rate: Some people mistakenly divide a 1% monthly rate by 360 as if it were a 12% annual rate. Actually, a 1% monthly rate corresponds to a 12% annual rate (monthly rate × 12). Some products have a 1% monthly rate with 12% annualization—don't mix them up.
Ignoring Compound Interest Effects: This calculator provides simple interest results. If the product uses daily compound interest (such as credit cards or certain online loans), actual interest will be slightly higher than simple interest; the longer the duration, the greater the difference.
Misusing Late Payment Penalties: Late payment penalties typically add 50%–100% on top of the original rate and cannot be calculated using the base rate directly; always check your contract.

Frequently Asked Questions (FAQ)

What is a daily rate of 0.05% equivalent to in annual terms?: 0.05% × 360 = 18%. So a daily rate of 0.05% is equivalent to 18% annualized, which is considered a high interest rate.
Can this calculator handle compound interest?: No, it only calculates simple interest. If you want to calculate daily compound interest, you'll need a separate compound interest calculator. However, you can use our daily interest rate as a simple interest reference; for short durations, compound interest effects are minimal.
Why do banks use 360 days instead of 365?: Historical convention for ease of calculation (months are 30 days). The People's Bank of China's "Regulations on RMB Interest Rate Management" also follows this rule. In rare cases (such as government bonds), 365 days may be used.
How do I convert between daily and monthly interest rates?: Monthly Rate = Daily Rate × 30 (regular months); Daily Rate = Monthly Rate ÷ 30; Annual Rate = Daily Rate × 360. In our calculator, you can directly enter either an annual or monthly rate, and the system automatically converts.
Are daily interest loans worthwhile?: It depends on the actual rate. Short-term loans (a few days) offer more flexibility than monthly accrual, but high rates mean substantial costs. Use our calculator to compute total interest and compare it with other options.
Is the interest rate fixed or floating?: The calculator assumes a fixed rate. Actual contracts may vary with floating rates, such as adjustments tied to LPR. Please refer to your contract.

Important Notes

Simple Interest Model: This tool applies only to simple interest scenarios (such as one-time repayment with interest or daily accrual until maturity). It is not precise for complex interest calculations such as compound interest or installment payments.
Interest Rate Unit: All interest rate inputs use percentages (e.g., 12 means 12%); do not include the percent sign. Results will also be displayed as percentages.
Business Convention: Different institutions may use different calculation rules (e.g., 365 days, 30 days/month). Please confirm what your loan agreement specifies. We offer a 360/365 day switch option.
Legal Limit: Annual rates exceeding 4 times the LPR (currently around 14%) are considered usury and are not legally enforceable. Calculation results are for estimation only.
Precision: Calculations are rounded to two decimal places (cents). In actual transactions, rounding to cents may cause minor differences.

Now you can try your own numbers in the calculator above.

Daily Interest Rate Calculator (2026)