SHAPES, DATA, AND SCHOOL MATH
Calculate the area and perimeter of a square, rectangle, triangle, or circle with shape-specific inputs and visible formulas.
Your result
Enter your values and select Calculate. Your result stays on this device.
Rectangle area = length × width; square area = side²; triangle area = base × height ÷ 2; circle area = π × radius².
Dimensions use the same linear unit. A triangle perimeter requires all three side lengths, so this tool reports triangle area only.
This free area calculator answers a broad U.S. search need without hiding which geometry formula is active. Choose a shape first, then enter only the measurements that apply to it.
Use case
Choose a square, rectangle, triangle, or circle, enter consistent dimensions, and calculate area with the active formula kept visible.
Calculate area for a common shape and review its perimeter or circumference when the entered dimensions support it.
Build a reliable scenario
Area and Perimeter Calculator helps you check a specific geometry & statistics question with figures that apply to you. Calculate the area and perimeter of a square, rectangle, triangle, or circle with shape-specific inputs and visible formulas. Choose a square, rectangle, triangle, or circle, enter consistent dimensions, and calculate area with the active formula kept visible. Calculate area for a common shape and review its perimeter or circumference when the entered dimensions support it. The page keeps the method and limits visible so the result can be understood, compared, and checked instead of treated as an unexplained answer.
Prepare Shape, Length, Width, Side length, Base and Perpendicular height. Choose square, rectangle, triangle, or circle. Enter dimensions in one consistent unit. Calculate and compare the area with the available perimeter or circumference result. For floors, lots, or material orders, verify measurements and use the project-specific square footage tool. Keep units, dates, currency, and time periods consistent.
The stated method is: Rectangle area = length × width; square area = side²; triangle area = base × height ÷ 2; circle area = π × radius². Change one assumption at a time to see which input drives the result, then compare scenarios on the same basis.
Dimensions use the same linear unit. A triangle perimeter requires all three side lengths, so this tool reports triangle area only. Check the input and rounding, then calculate again.
Source and update
Last reviewed: 2026-08-22
NIST Guide for the Use of the International System of UnitsMultiply length by width when both measurements use the same unit.
Yes for squares, rectangles, and circles. A triangle perimeter needs three sides, while this form asks for base and perpendicular height.
The interface labels feet for U.S. use. The same formulas work with any single consistent unit, and the area is expressed in that unit squared.
Keep exploring
Clear calculation guide
This free Area and Perimeter Calculator keeps the values and the calculation method visible instead of returning an unexplained number. Calculate the area and perimeter of a square, rectangle, triangle, or circle with shape-specific inputs and visible formulas. Use it to check a scenario with the figures that apply to you.
Start by checking units, dates, decimal places, and the option you selected. This free area calculator answers a broad U.S. search need without hiding which geometry formula is active. Choose a shape first, then enter only the measurements that apply to it. The stated mathematical method is: Rectangle area = length × width; square area = side²; triangle area = base × height ÷ 2; circle area = π × radius².
Change one assumption at a time to understand what moves the result, then keep any final record or institution-specific rule separate from the arithmetic. Dimensions use the same linear unit. A triangle perimeter requires all three side lengths, so this tool reports triangle area only. Hesaplayın is a clear, browser-based calculator for checking the maths behind your decision.