Simple Interest Calculator (Interest Only)

Simple Interest Calculator Calculate: Interest (I) Principal (P) Rate (r) Time Period (t) Where: I = Prt Principal (P): $     Rate (r):   % per day per month per quarter per year Time Period (t):     days months quarters years Answer: I = ? Equation: I = Prt Calculation: ?

Simple Interest Equation (Interest Only)

Where:

• I = Interest Amount
• P = Principal Amount
• r = Rate of Interest (decimal) per time period
• t = Time Periods involved

Notes: Base formula, written as I = Prt or I = P × r × t where rate r and time t should be in the same time units such as months or years. If you enter them differently this calculator will adjust the answer accordingly.  r is entered in % but converted and calculated in decimal form.

Time conversions are based on day count of 365 days/year, 30.4167 days/month and 91.2501 days/quarter.

Simple Interest Formulas and Calculations:

This calculator finds I, the simple interest where P is the Principal amount of money to be invested at an Interest Rate r% per period for t Number of Time Periods. Where r is in decimal form; r and t are in the same units of time.

• Calculate Interest
  • I = Prt
• Calculate Principal Amount, solve for P
  • P = I / rt
• Calculate rate of interest in decimal, solve for r
  • r = I / Pt
• Calculate rate of interest in percent
  • R = r * 100
• Calculate time, solve for t
  • t = I / Pr

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