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1. Print "Hello, World!"2. Add Two Numbers3. Swap Two Variables4. Find ASCII Value of a Character5. Check Even or Odd6. Find Largest of Two Numbers7. Find Largest of Three Numbers8. Check Positive, Negative, or Zero9. Convert Kilometers to Miles10. Convert Celsius to Fahrenheit11. Calculate Area of a Triangle12. Calculate Simple Interest13. Calculate Compound Interest14. Calculate Square Root15. Convert Seconds to Hours, Minutes, and Seconds16. Calculate Body Mass Index (BMI)17. Check Leap Year18. Find Absolute Value19. Calculate Age from Birth Year20. Sum of First N Natural Numbers21. Calculate Power Without Using pow()22. Print Multiplication Table23. Convert Decimal to Binary24. Convert Binary to Decimal25. Calculate Electricity Bill

Calculate Simple Interest in Python

SI = P*R*T / 100. Rate is percent, so 5 means 5%, not 0.05.

BeginnerBasic Python ProgramsExample 12 of 25
calculate-simple-interest.py
1# Program to calculate simple interest
2

3principal = float(input("Enter principal amount: "))
4rate = float(input("Enter annual interest rate (in %): "))
5time = float(input("Enter time in years: "))
6

7simple_interest = (principal * rate * time) / 100
8

9print("Simple Interest is:", simple_interest)

Output

Enter principal amount: 1000
Enter annual interest rate (in %): 5
Enter time in years: 2
Simple Interest is: 100.0

In this one

  • rate 5 means 5%, not 0.05
  • 1000, 5%, 2 years → 100

What's going on

SI = P × R × T / 100. R is already a percent. Enter 5 for 5%, not 0.05, or you undercharge by 100×.

People mix this up with compound interest and start raising to powers. Not here. Three multiplies and a divide.

1000 at 5% for 2 years is 100. If you don't get 100, you treated 5 as 0.05.

After this program

If the idea is still fuzzy, read Day 1: Introduction to Python in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 basic python programs, or see every topic on Python exercises.

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