We use cookies.This website uses essential cookies to operate core features. With your consent, we also use analytics cookies to understand traffic and improve the service. For more details, see our .
We use cookies.This website uses essential cookies to operate core features. With your consent, we also use analytics cookies to understand traffic and improve the service. For more details, see our .
Was this tool helpful to use?
Your feedback helps us make it better
Convert simple interest rates between annual, monthly and daily periods using the tool’s day-count basis.
Enter the interest rate value and select its period (annual/monthly/daily) on the right.
When converting annual to daily rates, specify the number of days in a year: 365 days for actual calendar days, 360 days for banking convention.
Please enter an interest rate to see conversion results.
Overview
Understand what the tool solves, how it works, and the boundaries of its data.
This converter expresses one nonnegative interest rate as annual, monthly, and daily percentages using a simple proportional relationship. Enter a rate as a percent number (for example, enter 6 for 6%), choose whether it is annual, monthly, or daily, then select a 360- or 365-day year. The results show all three periods, with the selected input identified.
Annual rate = monthly rate × 12
Annual rate = daily rate × selected days per year
Monthly rate = annual rate ÷ 12
Daily rate = annual rate ÷ selected days per year
These equations preserve a simple linear rate relationship. They do not model interest being added to principal between periods, nor do they calculate earnings in dollars.
The day basis is the denominator used to connect annual and daily rates. For an annual rate of 6%, the 365-day result is 6% ÷ 365 ≈ 0.016438% per day; the 360-day result is 6% ÷ 360 ≈ 0.016667% per day. Both leave the monthly result at 6% ÷ 12 = 0.5%. The 360/365 choice is a calculation assumption; it does not identify which convention a lender, account, security, or contract uses.
For context, TreasuryDirect describes its investment rate/yield as simple interest on a 365-day basis (366 in a leap year). US deposit-account APY rules instead account for interest and compounding under a separate formula. These are product-specific definitions and do not make either selection universally correct.
The output is a set of equivalent proportional rates under the chosen basis, not three independent quotes. If you enter a monthly rate of 0.5%, the annual simple equivalent is 0.5% × 12 = 6%. With the 365-day selection, the daily equivalent is 6% ÷ 365 ≈ 0.016438%. Switching to 360 changes that daily figure, while the annual and monthly values remain anchored to the entered monthly rate.
Displayed rates are rounded to at most six decimal places, with trailing zeroes removed. Small displayed differences can therefore arise from rounding; the underlying conversion uses the entered value and selected period.
Copy the quoted rate’s numeric percentage. If a document says 6%, enter 6 rather than 0.06.
Choose the period the quote actually represents: annual, monthly, or daily.
Set 360 or 365 to match the basis specified by the relevant terms or the comparison you intend to make.
Read the annual, monthly, and daily outputs, keeping the selected basis with any result you record.
When two quotes use different periods, convert them to a common simple-rate period for an initial comparison. Then check fees, payment timing, balance rules, and compounding in the original documents.
For a simple estimate that needs only an annual percentage and a day basis, convert the rate per day. A dollar interest estimate also needs principal and the number of days, which this tool does not take as inputs.
Use the matching period and day-basis assumptions to show how a quoted annual, monthly, or daily rate scales. Keep the assumptions beside the converted figures so they are not mistaken for a product’s official terms.
Guide
Follow the workflow and verify inputs and outputs with practical examples.
Use the number before the percent sign as the input. For example, 4.35% is entered as 4.35. Select the quote’s original period before reading the result; choosing a different period changes which value is treated as the starting point.
Choose the day basis deliberately. The converter starts at 365 days per year unless changed. Use the basis stated in the contract or product disclosure when you are reproducing its convention. If the source does not specify one, the result is only a comparison under your selected assumption.
Q&A
Find concise answers to common questions and confusing cases.
No. It scales rates proportionally. APY incorporates the frequency of compounding and follows a different calculation; use the product’s disclosed APY or a suitable compounding calculation for that purpose.
The annual rate is divided by the selected number of days. A smaller denominator (360) gives a slightly larger daily rate than 365. The correct basis depends on the specific agreement or product convention.
No. The converter does not ask for a principal, term, payment schedule, or fees. Loan payments and total borrowing cost require those details and may depend on compounding and cash-flow timing.
Enter a numeric rate of zero or greater and choose its period. Blank, nonnumeric, or negative input does not produce a result.
Notes
Review scope, result limitations, and important precautions before use.
This conversion is an arithmetic aid, not a statement of a financial product’s actual cost, return, legal compliance, or payment amount. Contracts can define accrual days, compounding, fees, balances, and payment timing differently. Confirm those terms in the applicable disclosure and do not treat a simple equivalent rate as APY or APR inclusive of fees.
Related
Discover related tools, collections, and available API capabilities.