Finance

Instant, private, and free

Interest per Day Calculator.

Calculate daily simple interest using an explicit day-count basis.

On-device calculationNo signup

Set your values

Results update as you type.

02 / ANSWER

Principal

Annual interest rate

Days in basis year

Interest per day

$0.00

FAQs

How does the interest per day calculator work?

Enter the requested values to see a deterministic result. Assumptions are explicit and no live market or tax data is fetched.

Use Cases

Estimate daily earnings on savings

Use this calculator to see how much interest your savings account earns each day based on the annual percentage yield (APY) and your balance.

Example: If you have $5,000 in a savings account with a 2% APY, you earn about $0.27 per day.

Calculate daily interest on loans

Determine the daily interest accruing on a loan or credit card balance to understand the cost of carrying debt.

Example: A $2,000 credit card balance at 18% APR accrues about $0.99 per day.

Frequently Asked Questions

How do I calculate interest per day?: To calculate interest per day, you need the principal amount, the annual interest rate, and the number of days. The formula is: (Principal × Annual Rate × Days) / 365. This gives you the total interest for that period, which you can then divide by the number of days to get the daily interest.
What is the formula for daily interest?: The formula for daily interest is: Daily Interest = (Principal × Annual Interest Rate) / 365. This assumes a 365-day year. For example, if you have $10,000 at a 5% annual rate, your daily interest would be ($10,000 × 0.05) / 365 = $1.37 per day.
Does this calculator account for compound interest?: This calculator is designed for simple interest calculations. It does not compound interest daily. For compound interest, you would need a different calculator that applies interest to the accumulated balance each day.

Tips & Common Mistakes

Tips

Use the annual interest rate (APR or APY) as a decimal or percentage, depending on the calculator's input format.
For accurate daily interest, use a 365-day year. Some calculators may use 360 days for certain financial products.
Remember that this calculator provides simple interest; for compound interest, the daily amount will change as interest is added to the principal.
Check if the calculator expects the rate as a percentage (e.g., 5) or a decimal (e.g., 0.05) to avoid errors.

Common Mistakes to Avoid

Entering the interest rate as a whole number instead of a decimal (e.g., 5 instead of 0.05) when the calculator expects a decimal.
Using the wrong number of days in a year (360 vs. 365) without adjusting for the calculator's assumption.
Forgetting to convert the annual rate to a daily rate if the calculator asks for a daily rate directly.

Last updated: August 13, 2026

Use Cases

Estimate daily earnings on savings

Use this calculator to see how much interest your savings account earns each day based on the annual percentage yield (APY) and your balance.

Example: If you have $5,000 in a savings account with a 2% APY, you earn about $0.27 per day.

Calculate daily interest on loans

Determine the daily interest accruing on a loan or credit card balance to understand the cost of carrying debt.

Example: A $2,000 credit card balance at 18% APR accrues about $0.99 per day.

Frequently Asked Questions

How do I calculate interest per day?

To calculate interest per day, you need the principal amount, the annual interest rate, and the number of days. The formula is: (Principal × Annual Rate × Days) / 365. This gives you the total interest for that period, which you can then divide by the number of days to get the daily interest.

What is the formula for daily interest?

The formula for daily interest is: Daily Interest = (Principal × Annual Interest Rate) / 365. This assumes a 365-day year. For example, if you have $10,000 at a 5% annual rate, your daily interest would be ($10,000 × 0.05) / 365 = $1.37 per day.

Does this calculator account for compound interest?

This calculator is designed for simple interest calculations. It does not compound interest daily. For compound interest, you would need a different calculator that applies interest to the accumulated balance each day.

Tips & Common Mistakes

Tips

Use the annual interest rate (APR or APY) as a decimal or percentage, depending on the calculator's input format.
For accurate daily interest, use a 365-day year. Some calculators may use 360 days for certain financial products.
Remember that this calculator provides simple interest; for compound interest, the daily amount will change as interest is added to the principal.
Check if the calculator expects the rate as a percentage (e.g., 5) or a decimal (e.g., 0.05) to avoid errors.

Common Mistakes to Avoid

Entering the interest rate as a whole number instead of a decimal (e.g., 5 instead of 0.05) when the calculator expects a decimal.
Using the wrong number of days in a year (360 vs. 365) without adjusting for the calculator's assumption.
Forgetting to convert the annual rate to a daily rate if the calculator asks for a daily rate directly.

Finance

Instant, private, and free

Interest per Day Calculator.

Calculate daily simple interest using an explicit day-count basis.

On-device calculationNo signup

Set your values

Results update as you type.

02 / ANSWER

Principal

Annual interest rate

Days in basis year

Interest per day

$0.00

FAQs

How does the interest per day calculator work?

Enter the requested values to see a deterministic result. Assumptions are explicit and no live market or tax data is fetched.

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Use Cases

Estimate daily earnings on savings

Use this calculator to see how much interest your savings account earns each day based on the annual percentage yield (APY) and your balance.

Example: If you have $5,000 in a savings account with a 2% APY, you earn about $0.27 per day.

Calculate daily interest on loans

Determine the daily interest accruing on a loan or credit card balance to understand the cost of carrying debt.

Example: A $2,000 credit card balance at 18% APR accrues about $0.99 per day.

Frequently Asked Questions

How do I calculate interest per day?: To calculate interest per day, you need the principal amount, the annual interest rate, and the number of days. The formula is: (Principal × Annual Rate × Days) / 365. This gives you the total interest for that period, which you can then divide by the number of days to get the daily interest.
What is the formula for daily interest?: The formula for daily interest is: Daily Interest = (Principal × Annual Interest Rate) / 365. This assumes a 365-day year. For example, if you have $10,000 at a 5% annual rate, your daily interest would be ($10,000 × 0.05) / 365 = $1.37 per day.
Does this calculator account for compound interest?: This calculator is designed for simple interest calculations. It does not compound interest daily. For compound interest, you would need a different calculator that applies interest to the accumulated balance each day.

Tips & Common Mistakes

Tips

Use the annual interest rate (APR or APY) as a decimal or percentage, depending on the calculator's input format.
For accurate daily interest, use a 365-day year. Some calculators may use 360 days for certain financial products.
Remember that this calculator provides simple interest; for compound interest, the daily amount will change as interest is added to the principal.
Check if the calculator expects the rate as a percentage (e.g., 5) or a decimal (e.g., 0.05) to avoid errors.

Common Mistakes to Avoid

Entering the interest rate as a whole number instead of a decimal (e.g., 5 instead of 0.05) when the calculator expects a decimal.
Using the wrong number of days in a year (360 vs. 365) without adjusting for the calculator's assumption.
Forgetting to convert the annual rate to a daily rate if the calculator asks for a daily rate directly.

Last updated: August 13, 2026