Half-Angle Calculator
Half-Angle with stated conventions, validation and a worked example.
Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Angles are in degrees unless the unit selector says otherwise. Outputs are numerical approximations. A denominator with magnitude below 10⁻¹² is treated as singular.
Example Calculation
- Full angle: 120 °
θ=120° gives θ/2=60° and sine √3/2. The full angle is halved before normalization.
Method references
Frequently asked questions
How do I use this calculator?
Enter full angle. The result updates automatically. Use Reset to restore the example values.
What method does it use?
sin(θ/2), cos(θ/2), tan(θ/2); the signs follow the quadrant of the actual half-angle.. Angles are in degrees unless the unit selector says otherwise. Outputs are numerical approximations. A denominator with magnitude below 10⁻¹² is treated as singular.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.