RADIANS function: convert degree angles before SIN, COS, and TAN

Why trigonometric functions need RADIANS

Field specs, CAD drawings, and roof pitches are almost always recorded in degrees (such as 30° or 45°), whereas SIN, COS, and TAN expect angles in radians where a half-circle (180°) equals pi (about 3.141593).

Passing 30 directly into SIN(30) evaluates 30 radians—nearly five full rotations—and returns -0.988032 instead of 0.5. Wrapping the degree cell in RADIANS(angle) multiplies by PI()/180 cleanly.

Calculate vertical rise on an inclined conveyor

For a 14-meter conveyor inclined at 30 degrees, vertical lift equals belt_length * SIN(RADIANS(angle_deg)) = 14 * 0.5 = 7 meters.

=ROUND(B2 * SIN(RADIANS(A3)), 4)

Zero and negative angles

RADIANS preserves sign and zero: 0° maps to 0 radians, and a -15° downward slope maps to -0.261799 radians.

=ROUND(RADIANS(A5), 6)

Further reading

• Microsoft Support — RADIANS function