*I AM NOT A FINANCIAL ADVISOR. DO YOUR OWN RESEARCH* This calculation works for both consumer and commercial loans. I get asked the "how much will my payment be" question all the time at work, especially for Home Equity Lines of Credit. Principal Balance: The amount outstanding on the loan. if you have a $200,000 HELOC but only used half of it you are only charged interest on the $100,000 Interest rate: Your annual interest rate. Daily Interest: Interest only loans usually accrue daily. First take your rate (4% = 0.04) and divide by 365 (360 for commercial loans). This gives you the percentage of interest being charged per day. Multiply by the principal balance to get your daily Interest accrual. Payment: multiply the interest accrual by the number of days in the pay period (usually the number of days in the previous month). Not if you took additional money or paid the line down in the middle of the month you will have to calculate the daily interest for each principal balance and multiply by the number of days at each Music from Benspace.com Not my own. Don't sue me Mr. Space.