Math and Algebra
Perimeter Calculator
Perimeter Calculator calculate the boundary length of a rectangle, square, triangle, regular polygon, or circle using shape-specific inputs.
Math and Algebra
Perimeter Calculator
Calculate the boundary length of a rectangle, square, triangle, regular polygon, or circle using shape-specific inputs.
Formula
Rectangle: 2(L+W); square: 4s; triangle: a+b+c; regular polygon: n*s; circle: 2*pi*r.
About the Perimeter Calculator
Calculate the boundary length of a rectangle, square, triangle, regular polygon, or circle using shape-specific inputs.
How the Perimeter Calculator Works
The selected shape activates its own formula and validates only the measurements required by that shape.
Formula
Rectangle: 2(L+W); square: 4s; triangle: a+b+c; regular polygon: n*s; circle: 2*pi*r.
The calculation runs in your browser. Values are validated for required ranges, compatible units, and method-specific restrictions before results are displayed.
Required Inputs
- Shape (required).
- Rectangle length (optional).
- Rectangle width (optional).
- Square side (optional).
- Triangle side a (optional).
- Triangle side b (optional).
- Triangle side c (optional).
- Polygon sides (optional).
- Polygon side length (optional).
- Circle radius (optional).
Results Reported
The result panel reports the final answer and the intermediate quantities needed to check the calculation:
- Shape
- Perimeter
- Measurements used
Perimeter Calculator Example
Select Example Data in the calculator to load this reproducible input set:
| Input | Example value |
|---|---|
| Shape | rectangle |
| Rectangle length | 10 |
| Rectangle width | 6 |
| Square side | 5 |
| Triangle side a | 3 |
| Triangle side b | 4 |
| Triangle side c | 5 |
| Polygon sides | 6 |
| Polygon side length | 4 |
| Circle radius | 5 |
How to Use the Calculator
- Confirm that the calculator title and formula match the quantity you need.
- Enter every required value using the unit shown with its field.
- Select Example Data to inspect a valid input set, or enter your own values and select Calculate.
- Review all reported values and the displayed formula before using the answer.
- Use Copy Result or Download CSV when you need a reusable record.
Accuracy and Limitations
Lengths must use one consistent unit. A triangle must satisfy the triangle inequality, and a regular polygon needs at least three sides.
Keep units consistent, use measurements that represent the actual situation, retain full precision during the calculation, and round only the final answer. Professional decisions may require current official rules, field measurements, laboratory methods, or specialist review.
Frequently Asked Questions
What does the Perimeter Calculator calculate?
Calculate the boundary length of a rectangle, square, triangle, regular polygon, or circle using shape-specific inputs.
Which formula does the Perimeter Calculator use?
Rectangle: 2(L+W); square: 4s; triangle: a+b+c; regular polygon: n*s; circle: 2*pi*r.
What should I verify before using this result?
Lengths must use one consistent unit. A triangle must satisfy the triangle inequality, and a regular polygon needs at least three sides.