What per diem interest means
Per diem means per day. On a bridge loan, the per diem is the interest charged for each day the loan is outstanding: the balance times the annual rate, divided by the number of days in the year your note uses. Lenders quote it on payoff statements so you can work out the exact amount for the day you close.
Many US commercial and hard money notes use a 360-day year, which makes each day slightly more expensive than a 365-day basis. Your note states which basis applies, often as Actual/360 or Actual/365.
360 versus 365 days
On $250,000 at 11% a year, the per diem is $76.39 on a 360-day basis and $75.34 on a 365-day basis. Over 135 days, that difference adds up to $141.27 more interest on the 360-day basis, because a full calendar year of actual days is charged at a rate set for 360.
Some notes also require a minimum amount of interest, such as 90 days, even if you pay off sooner. Enter it under Minimum interest period, and the calculator charges the greater of the actual days and the minimum.
Worked example: a 135-day bridge
A $250,000 bridge loan funds on November 2, 2026 and is paid off on March 17, 2027, which is 135 days. At 11% a year on a 360-day basis, the per diem is $76.39 and interest totals $10,312.50. With 2 origination points ($5,000), the total cost of borrowing is $15,312.50 and the payoff amount is $260,312.50.
What this calculator does not include
This works out simple daily interest on a constant balance. It does not include late charges, default interest, extension fees, recording or wire fees on the payoff statement, or interest already paid in monthly installments. Always confirm against the lender's written payoff statement.
For the full cost of a bridge between two homes, use the US swing loan calculator .
To check how much you can borrow against your home, use the US bridge loan LTV calculator .
Use the right country page
This page stays in US dollars and uses US terms: an annual rate, per diem interest, a 360-day default basis and a payoff amount. The country choices above the inputs open separate local pages. Choosing United Kingdom opens the UK daily interest bridging loan calculator, which uses a monthly rate converted on a 365-day year. The inputs reset and amounts are not converted.
Inputs for the bridge loan per diem calculator
Loan balance
The principal outstanding that interest is charged on.
Quoted interest rate
The note rate, not the APR. US bridge loans are usually quoted per year.
Rate quoted per
Year for an annual rate; Month for a monthly rate, which is multiplied by 12.
Days in the year
The day-count basis in your note: 360 for Actual/360, 365 for Actual/365.
Funding date
The date the loan was funded.
Payoff date
The date you expect to pay the loan off in full.
Minimum interest period
The fewest days of interest the note requires, if any. Enter zero if none.
Origination fee (points)
One point is 1% of the loan, paid at closing.
Exit fee
A percentage some lenders charge at payoff. Enter zero if none.
Other costs
Appraisal, title, legal and broker costs paid separately.
CALCULATOR QUESTIONS
US bridge loan per diem calculator questions
How do I calculate per diem interest on a loan?
Multiply the loan balance by the annual rate and divide by the number of days in the year your note uses, 360 or 365. Multiply that per diem by the number of days to get the interest.
Why does my lender use 360 days?
Many commercial and hard money notes use an Actual/360 basis. It charges each actual day at a rate set for a 360-day year, so it costs slightly more than Actual/365.
What is a payoff amount?
The total needed to repay the loan on a specific date: the principal, interest to that date and any exit fee, plus any charges on the lender's payoff statement.
Is there a minimum interest charge?
Some bridge and hard money notes require a minimum number of days of interest even if you pay off early. Check your note and enter it in the calculator.
What happens when I change country?
The United Kingdom option opens the separate UK daily interest bridging loan page, in pounds, with a monthly rate and a 365-day default. Your inputs are reset rather than converted.