Longitude Degrees to Miles Calculator

This calculator converts longitude degrees to miles, showing the distance between two points on Earth's surface along a line of constant latitude. It's useful for navigation, geography, and distance calculations.

How to Use This Calculator

To calculate the distance between two longitude points in miles:

Enter the first longitude in degrees in the "First Longitude" field
Enter the second longitude in degrees in the "Second Longitude" field
Select the latitude at which you want to calculate the distance
Click "Calculate" to see the result in miles

The calculator will display the distance between the two longitude points along the specified latitude.

Formula Explained

The distance between two longitude points (λ₁ and λ₂) at a given latitude (φ) is calculated using the following formula:

Distance (miles) = |λ₂ - λ₁| × cos(φ) × (Earth's radius in miles)

Where:

λ₁ and λ₂ are the two longitude values in degrees
φ is the latitude in degrees
Earth's radius ≈ 3,959 miles

This formula accounts for the fact that the distance between longitude lines decreases as you move away from the equator.

Worked Examples

Example 1: Equator Calculation

Calculate the distance between 30°W and 40°E at the equator (0° latitude):

Distance = |40 - (-30)| × cos(0) × 3,959 = 70 × 1 × 3,959 = 277,130 miles

Example 2: Mid-Latitude Calculation

Calculate the distance between 120°W and 60°W at 45°N latitude:

Distance = |60 - (-120)| × cos(45) × 3,959 = 180 × 0.7071 × 3,959 ≈ 48,900 miles

Frequently Asked Questions

What is the difference between longitude and latitude?: Longitude measures east-west position (0° to ±180°), while latitude measures north-south position (0° to ±90°).
Why does the distance between longitude lines change with latitude?: Longitude lines converge at the poles, so they're closest at the equator and farthest apart at the poles.
Can I use this calculator for air travel distances?: This calculator shows the straight-line distance along a constant latitude. For actual flight paths, you'd need to account for the curvature of the Earth.
What's the maximum possible longitude distance?: The maximum distance between two longitude points is 20,039 miles (half the Earth's circumference at the equator).