Square Foot Calculator Irregular Shape
Calculate the square footage of any irregular shape. Enter coordinate points to calculate the area using the Shoelace formula.
Irregular Shape Calculator
Enter at least 3 coordinate points (X, Y) that define the corners of your shape. Points should be in order (clockwise or counter-clockwise).
Enter X,Y coordinates for each point.
Points must go in order around the shape.
How to Calculate Square Footage of an Irregular Shape
When a shape doesn't fit any standard formula, use coordinate geometry. By plotting corner points on an X-Y grid, the Shoelace formula calculates the exact area of any polygon.
Shoelace Formula
List the X and Y coordinates of each corner in order (clockwise or counter-clockwise). The formula sums cross-products of consecutive points to find the enclosed area.
How to Set Up Coordinates
- Pick a reference corner as your origin (0, 0).
- Measure distances from the origin to each corner — X is left-right, Y is up-down.
- Enter all points in order around the shape.
- Click calculate — the formula automatically closes the polygon.
Example
Points: (0,0), (10,0), (12,8), (5,12), (0,6)
Shoelace result = 106 square feet
Tips
- Points must go in order around the perimeter — don't criss-cross.
- Works for any number of sides (3+).
- For curved boundaries, add more points along the curve for accuracy.
Frequently Asked Questions
How does the Shoelace formula work? +
The Shoelace formula calculates the area of any polygon given its corner coordinates. It sums the cross-products of consecutive point pairs and divides by 2.
How do I set up coordinates for my irregular shape? +
Pick one corner as the origin (0,0). Measure X (left-right) and Y (up-down) distances from the origin to each corner, going in order around the shape.
Do the points need to be in a specific order? +
Yes, points must go in order around the perimeter (clockwise or counter-clockwise). Do not criss-cross. The formula automatically closes the polygon.
How many points do I need? +
Minimum 3 points (triangle). For more complex shapes, add more points along curved boundaries for better accuracy.