Last updated: July 31, 2026
Equilateral Triangle Calculator
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Formula
perimeter=3s; height=(√3/2)s; area=(√3/4)s^2; inradius=s/(2√3); circumradius=s/√3
Where:
- s=s
Worked Examples
Side length 6
Simple integer side.
- 1P=3s=18
- 2h=(√3/2)6
- 3A=(√3/4)36
Side length 10
Larger triangle.
- 1Apply all five formulas
Decimal side length
s=2.5.
- 1Use same formulas with decimal s
Introduction
Compute all major geometric properties of an equilateral triangle from one side length.
Formula and Method
Equilateral Triangle Calculator uses: perimeter=3s; height=(√3/2)s; area=(√3/4)s^2; inradius=s/(2√3); circumradius=s/√3
Enter all required inputs
Apply the underlying math formula(s)
Compute supporting terms where needed
Round numeric outputs for stable display
Input Fields
Provide values for: s.
- 1
s: s
Output Fields
The calculator returns: perimeter, height, area, inradius, circumradius.
- 1
perimeter: Triangle perimeter
- 2
height: Triangle height (altitude)
- 3
area: Triangle area
- 4
inradius: Radius of inscribed circle
- 5
circumradius: Radius of circumscribed circle
Validation Rules
Input validation is applied before calculation to prevent invalid math states.
s must be a finite number.
s must be positive.
All formulas assume an exact equilateral triangle.
Outputs are rounded to 6 decimals.
How to Use This Calculator
Fill in the inputs, run the calculator, and review primary output first.
Enter the required values
Click calculate
Check the primary output
Use example scenarios for verification
Practical Uses
This calculator supports learning, quick checks, and day-to-day technical problem solving.
Homework and exam preparation
Engineering and science sanity checks
Classroom demonstrations
Fast recalculation with different inputs
FAQs
What does the Equilateral Triangle Calculator compute?
Compute all major geometric properties of an equilateral triangle from one side length.
Which inputs are required?
Required inputs: s.
How should I format numbers?
Use finite numeric values; decimals and negative numbers are allowed unless restricted by validation rules.
How are results rounded?
Numeric outputs are rounded to about 6 decimal places for readability.
Why might I see an error?
s must be a finite number.
Can I use this for learning and verification?
Yes. Use the examples and formula section to verify manual calculations quickly.