Simple flat rate interest calculator: calculate the due interest on an amount of money lent, deposited or borrowed by the interest rate, principal (starting amount), duration and additional transactional fees (withdrawal, payment in advance)

Calculate simple flat rate interest on a principal borrowed, lent

Simple flat rate interest = (Principal × Annual simple flat interest rate × Duration in days) ÷ Number of days in a year

Latest calculated simple flat rate interest values

Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 0 units (Dollar, Euro, Pound, etc.), from date: May 24, 0958, to date: Jan 24, 2017, namely for a period of 386,672 days (12,704 Months), with an annual simple flat interest rate of - 3% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 0.11 units (Dollar, Euro, Pound, etc.), from date: May 14, 0142, to date: Jun 30, 0810, namely for a period of 244,029 days (8,017 Months and 16 Days), with an annual simple flat interest rate of 6% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 0 units (Dollar, Euro, Pound, etc.), from date: May 24, 0958, to date: Jan 24, 2017, namely for a period of 386,672 days (12,704 Months), with an annual simple flat interest rate of - 3% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 100 units (Dollar, Euro, Pound, etc.), from date: Feb 10, 2019, to date: Mar 10, 2019, namely for a period of 28 days, with an annual simple flat interest rate of 10% if the commission fee (withdrawal) is 448%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 24,500,000 units (Dollar, Euro, Pound, etc.), from date: Feb 27, 1985, to date: Feb 27, 2019, namely for a period of 12,418 days (408 Months), with an annual simple flat interest rate of 804% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 15,000 units (Dollar, Euro, Pound, etc.), from date: Jul 30, 2019, to date: Jul 30, 2020, namely for a period of 366 days (12 Months), with an annual simple flat interest rate of 7% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 1,862,400 units (Dollar, Euro, Pound, etc.), from date: Mar 13, 0780, to date: Feb 13, 2018, namely for a period of 452,142 days (14,855 Months), with an annual simple flat interest rate of 39% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 1,862,400 units (Dollar, Euro, Pound, etc.), from date: Mar 13, 0780, to date: Feb 13, 2018, namely for a period of 452,142 days (14,855 Months), with an annual simple flat interest rate of 39% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 1 units (Dollar, Euro, Pound, etc.), from date: Oct 25, 0318, to date: Nov 01, 2018, namely for a period of 620,920 days (20,401 Months without 24 Days), with an annual simple flat interest rate of 506% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 1 units (Dollar, Euro, Pound, etc.), from date: Oct 25, 0318, to date: Nov 01, 2018, namely for a period of 620,920 days (20,401 Months without 24 Days), with an annual simple flat interest rate of 506% if the commission fee (withdrawal) is 0%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of - 1,650 units (Dollar, Euro, Pound, etc.), from date: Jan 21, 1998, to date: Apr 21, 2020, namely for a period of 8,126 days (267 Months), with an annual simple flat interest rate of 0.01% if the commission fee (withdrawal) is 576%. May 18 01:30 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 0 units (Dollar, Euro, Pound, etc.), from date: Jul 19, 0582, to date: Feb 19, 2017, namely for a period of 523,973 days (17,215 Months), with an annual simple flat interest rate of 3% if the commission fee (withdrawal) is 0%. May 18 01:29 UTC (GMT)
Calculate due interest earned by a principal (initial amount of money lent, deposited or borrowed) of 19,999 units (Dollar, Euro, Pound, etc.), from date: Jan 06, 0116, to date: Jan 06, 2022, namely for a period of 696,153 days (22,872 Months), with an annual simple flat interest rate of 6.25% if the commission fee (withdrawal) is 0%. May 18 01:29 UTC (GMT)
All users calculated simple flat rate interest values


Simple flat rate interest.

Interest

  • When someone lends money to someone else, the borrower usually pays a fee to the lender. So the due interest is a sum paid or charged for the use of money or for borrowing money. The interest depends on: 1) the period of the loan 2) the amount of money lent or borrowed (called principal) and 3) the interest rate (the percentage of the principal charged as interest).
  • For example, for some bank deposits is not uncommon to pay an interest rate of 3.5% on the principal, annualy. Banks are also using these temporarily owned amounts of money by introducing them back into the cash flow circuit or are granting loans (for investments, for example) on which they are again charging interest.

Annual simple flat interest rate

  • The simple annual interest rate, or the percentage of the principal charged as interest for a period of one year, shows us that for an amount of 100 units (ex: Dollar, Euro, Yen, Pound, Franc), in a year, the interest is calculated as a percentage p% of the principal: I = p% × 100 units.
  • A deposit of S units generates a one year simple interest of: I = S × p% units, and in n years, the same deposit of S units generates an interest of: I = S × p% × n units.

Annual simple flat rate interest formula:

  • I = S × p% × n

  • I = n years simple flat rate interest charged
  • S = initial amount (principal)
  • p% = annual simple flat interest rate (percentage of the principal charged as interest)
  • n = number of years of the lending or borrowing the money

Examples of how the simple flat rate interest formula works:

  • 1) What interest, I, generates in n = 5 years a principal of S = 20,000 units if the annual simple flat interest rate is p% = 3.5%?
    Answer:
    I = S × p% × n = 20,000 × 3.5% × 5 = 20,000 × 3.5 ÷ 100 × 5 = 1,000 × 3.5 = 3,500 units
  • 2) What is the simple flat interest rate, p%, if a principal of S = 12,000 units is charged a n = 6 years interest of I = 2,880 units?
    Answer:
    I = S × p% × n =>
    p% = I ÷ (S × n) = 2,880 ÷ (12,000 × 6) = 0.04 = 4%.

Annual simple flat rate interest formula calculated for a period of n years:

  • Interest, I = S × p% × n
  • Principal, S = I ÷ (p% × n)
  • Interest rate, p% = I ÷ (S × n)
  • Number of years (period): n = I ÷ (S × p%)

Annual simple flat rate interest formula calculated for a period of m months:

  • Interest, I = (S × p% × m) ÷ 12
  • Principal, S = (12 × I) ÷ (p% × m)
  • Interest rate, p% = (12 × I) ÷ (S × m)
  • Number of months of the period, m = (12 × I) ÷ (S × p%)

Annual simple flat rate interest formula calculated for a period of d days:

  • Interest, I = (S × p% × d) ÷ 365
  • Principal, S = (365 × I) ÷ (p% × d)
  • Simple flat interest rate, p% = (365 × I) ÷ (S × d)
  • Number of days of the period, d = (365 × I) ÷ (S × p%)

More examples of how the simple flat rate interest formula works:

  • 1) Calculate the due interest on a principal of S = 400 units in m = 5 months, with a simple flat interest rate of p% = 4%.
    Answer:
    I = (S × p% × m) ÷ 12 = (400 × 4% × 5) ÷ 12 = (400 × 4 ÷ 100 × 5) ÷ 12 = 16 × 5 ÷ 12 = 20 ÷ 3 = 6.67 units
  • 2) Calculate the due interest generated by a principal of S = 400 units in m = 5 months if the simple flat interest rate of p% = 4.5%.
    Answer:
    I = (S × p% × m) ÷ 12 = (400 × 4.5% × 5) ÷ 12 = (400 × 4.5 ÷ 100 × 5) ÷ 12 = 18 × 5 ÷ 12 = 15 ÷ 2 = 7.5 units.