EVERYDAY CLARITY
Triangle Perimeter Calculator
What is the perimeter of a triangle with these three sides? Enter the values below to calculate the result.
Your result
perimeter
length
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Side a (length) | Enter side a in length; use the same basis as the other measurements. |
| Side b (length) | Enter side b in length; use the same basis as the other measurements. |
| Side c (length) | Enter side c in length; use the same basis as the other measurements. |
Understanding your result
Read perimeter (length) in the units and model stated on this page. The formula perimeter=a+b+c defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Mixing input units or changing the physical meaning of a variable without changing the model.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
What is the perimeter of a triangle with these three sides?
What is the perimeter of a triangle with these three sides? Enter the values below to calculate the result.
Common uses
- What is the perimeter of a triangle with these three sides
How it works
perimeter=a+b+c
Worked example
Enter Side a: 3 length; Side b: 4 length; Side c: 5 length. Results: perimeter: 12 length.