CPA / TCPA Calculator

Calculate Closest Point of Approach and Time to CPA for collision avoidance.

Own Ship Speed (knots)

Own Ship Course (°)

Target Speed (knots)

Target Course (°)

Target Range (NM)

Target Bearing (°)

CPA (NM) —

TCPA (minutes) —

What is CPA / TCPA?

CPA = Closest Point of Approach (minimum distance between two ships).

TCPA = Time to Closest Point of Approach.

Useful for bridge officers using radar for collision avoidance and ARPA training.

This is a simplified vector calculation. Always cross-check with ARPA and visual observations.