Work out slope angle from gradient instantly with clear inputs, formula shown and shareable results.
Gradient is rise divided by run, and the slope angle is its arctangent. A grade quoted as a percentage is simply the gradient times 100, so a 1-in-12 ramp is an 8.33% grade at about 4.76°.
Slope angle
θ = arctan(rise / run)
Grade
grade % = 100 × rise / run
Gradient 0.25, grade 25% and an angle of arctan 0.25 ≈ 14.0362°.
No, it is 45°. A vertical drop has an infinite gradient, which is why grades above about 30% are rare on roads.