Python Program to Convert Celsius to Fahrenheit

You can convert Celsius to Fahrenheit in Python using the formula fahrenheit = (celsius * 9/5) + 32. For example, fahrenheit = (celsius * 9/5) + 32 converts Celsius temperature to Fahrenheit.

Examples

Input0

Output32.0

Input25

Output77.0

Input-40

Output-40.0

How to Think About It

To convert Celsius to Fahrenheit, multiply the Celsius temperature by 9, then divide by 5, and finally add 32. This formula adjusts the scale and offset between the two temperature units.

Algorithm

1

Get the temperature value in Celsius from the user or input.

2

Multiply the Celsius value by 9.

3

Divide the result by 5.

4

Add 32 to the result to get Fahrenheit.

5

Return or print the Fahrenheit temperature.

Code

python

celsius = float(input('Enter temperature in Celsius: '))
fahrenheit = (celsius * 9 / 5) + 32
print(f'{celsius}°C is {fahrenheit}°F')

Output

Enter temperature in Celsius: 25
25.0°C is 77.0°F

Dry Run

Let's trace converting 25°C to Fahrenheit through the code

1

Input Celsius

User inputs 25, so celsius = 25.0

2

Multiply by 9

25.0 * 9 = 225.0

3

Divide by 5

225.0 / 5 = 45.0

4

Add 32

45.0 + 32 = 77.0

5

Print result

Output: '25.0°C is 77.0°F'

Step	Operation	Value
1	Input Celsius	25.0
2	Multiply by 9	225.0
3	Divide by 5	45.0
4	Add 32	77.0
5	Print result	25.0°C is 77.0°F

Why This Works

Step 1: Multiply Celsius by 9

Multiplying by 9 scales the Celsius temperature to the Fahrenheit scale proportionally.

Step 2: Divide by 5

Dividing by 5 adjusts the ratio between Celsius and Fahrenheit degrees.

Step 3: Add 32

Adding 32 shifts the zero point from Celsius to Fahrenheit, aligning freezing points.

Alternative Approaches

Using a function

python

def celsius_to_fahrenheit(celsius):
    return (celsius * 9 / 5) + 32

print(celsius_to_fahrenheit(25))

This approach makes the conversion reusable and cleaner for multiple values.

Using lambda expression

python

c_to_f = lambda c: (c * 9 / 5) + 32
print(c_to_f(25))

A concise way to define the conversion in one line, useful for quick calculations.

Complexity: O(1) time, O(1) space

Time Complexity

The calculation uses a fixed number of arithmetic operations, so it runs in constant time.

Space Complexity

Only a few variables are used, so the space needed is constant.

Which Approach is Fastest?

All approaches run in constant time; using a function or lambda improves code reuse but does not affect speed.

Approach	Time	Space	Best For
Direct calculation	O(1)	O(1)	Simple one-time conversion
Function	O(1)	O(1)	Reusable conversions
Lambda expression	O(1)	O(1)	Concise inline use