Use this free online area calculator to find the area of squares, rectangles, circles, triangles, and trapezoids. Simply pick your shape, enter its dimensions, and get an accurate area calculation instantly.
How to Use the Area Calculator
Select your "Shape" - square, rectangle, circle, triangle, or trapezoid.
Enter the required dimensions for that shape (e.g. Side for a square, Length and Width for a rectangle, Radius for a circle, Base and Height for a triangle, or Base 1, Base 2, and Height for a trapezoid).
Click "Calculate" to compute the area.
Review the "Area" result shown below the button.
Frequently Asked Questions
Square uses side², rectangle uses length × width, circle uses π × radius², triangle uses 0.5 × base × height, and trapezoid uses 0.5 × (base1 + base2) × height.
All dimensions must be positive numbers greater than zero. Leaving a required field blank or entering zero or negative values produces an error message specific to that shape instead of a result.
For base1 = 6, base2 = 4, and height = 3, the area is 0.5 × (6 + 4) × 3 = 15 square units.
Yes, it's completely free with no sign-up required, and results are rounded to three decimal places.