How accrued interest is worked out
Daily interest is the balance × the yearly rate ÷ the days in the year. Multiply by the number of days between the dates, counting the start day but not the end day, to get the interest accrued.
Worked example
£10,000 at 7% a year builds £1.92 of interest a day. From 1 November to 1 December 2026, 30 days, that's £57.53. On a 360-day year it would be £58.33.
Which rate to enter
Use the yearly interest rate the lender charges, not the APR, which also includes fees and compounding. Most UK loans and mortgages, including business loans in pounds, divide by 365. A 360-day year is mainly used for loans in US dollars or euros, though some lenders write it into their contracts, so check your agreement.
What this calculator assumes
Simple interest on a balance that doesn't change, and the same 365-day year in leap years. Lenders may round the daily figure to pennies.
Borrowing in the US?
The country choices above the inputs open separate local pages. US loans call daily interest the per diem and often use a 360-day year. Choosing United States opens that page and resets the inputs; amounts are not converted.
For the US version, use the US loan interest accrual calculator in US dollars.
Inputs for the UK loan accrued interest calculator
Loan balance
The amount owed, in pounds.
Yearly interest rate
The rate the lender charges, not the APR.
Days in the year
Usually 365 for UK loans.
From
When interest starts building.
To
The date you want the interest up to.
CALCULATOR QUESTIONS
UK loan accrued interest calculator questions
How do you calculate accrued interest on a loan?
Balance × rate ÷ 365 × days. £10,000 at 7% for 30 days is £57.53.
Is the start or end date counted?
One of them, not both: the calculator counts the days from the start date up to, but not including, the end date.
Why use 360 days?
Some lenders, mostly for dollar and euro loans, use a 360-day year, which makes each day's interest slightly higher.
Is accrued interest the same as my settlement figure?
No. Your settlement figure is the balance plus interest to the settlement date, which may also include a charge.