JavaScript/Basic Programs/Program

Convert Fahrenheit to Celsius

Program to convert temperature from Fahrenheit to Celsius

JavaScriptBeginner

JavaScript

// Formula: Celsius = (Fahrenheit - 32) * 5/9
let fahrenheit = 98.6;
let celsius = (fahrenheit - 32) * 5 / 9;

console.log(`${fahrenheit}°F = ${celsius.toFixed(2)}°C`);

// Function version
function fahrenheitToCelsius(f) {
    return (f - 32) * 5 / 9;
}

let temp1 = fahrenheitToCelsius(32);   // Freezing point
let temp2 = fahrenheitToCelsius(212);  // Boiling point
let temp3 = fahrenheitToCelsius(98.6); // Body temperature

console.log(`32°F = ${temp1}°C`);
console.log(`212°F = ${temp2}°C`);
console.log(`98.6°F = ${temp3.toFixed(2)}°C`);

Output

98.6°F = 37.00°C
32°F = 0°C
212°F = 100°C
98.6°F = 37.00°C

This program demonstrates temperature conversion and working with decimal numbers.

Temperature Conversion Formula

Celsius = (Fahrenheit - 32) × 5/9

Key Points:

Subtract 32 from Fahrenheit
Multiply by 5/9 (or 0.5556)
Result is in Celsius

Common Temperatures:

Freezing: 32°F = 0°C
Boiling: 212°F = 100°C
Body temp: 98.6°F = 37°C
Room temp: 68°F = 20°C

Working with Decimals

JavaScript handles floating-point arithmetic:

javascript
let result = (98.6 - 32) * 5 / 9;
// Result: 37.00000000000001 (floating point precision)

Rounding Methods

toFixed(n): Rounds to n decimal places, returns string

javascript
(37.00001).toFixed(2); // "37.00"

Math.round(): Rounds to nearest integer

javascript
Math.round(37.6); // 38

Math.floor(): Rounds down

javascript
Math.floor(37.9); // 37

Math.ceil(): Rounds up

javascript
Math.ceil(37.1); // 38

Function Approach

Creating a reusable function:

javascript
function fahrenheitToCelsius(f) {
    return (f - 32) * 5 / 9;
}

Benefits:

Reusable code
Clear purpose
Easy to test
Can be called multiple times

Reverse Conversion

Celsius to Fahrenheit:

javascript
function celsiusToFahrenheit(c) {
    return (c * 9 / 5) + 32;
}

Arithmetic Operations

Calculate Simple Interest