Offset Calculator
Compute coordinates of a point offset perpendicularly from a centerline, given start point, bearing, distance along and offset distance.
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Result
About offset surveying
Offset calculations are fundamental in road, railway, and infrastructure staking. Given a point on a centerline and its bearing (direction), you can compute any point offset perpendicular to the centerline by a specified distance. The formula uses bearings (angles measured from true north clockwise) and basic trigonometry.
This tool computes the final coordinates of an offset point from a starting point, travel distance along the bearing, and perpendicular offset distance (left or right of the direction of travel). The "left" or "right" convention is defined relative to facing the direction of travel along the line.
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Common use cases
Staking right-of-way boundaries offset from a road centerline.
Computing coordinates of pipeline trench offsets from an existing alignment.
Setting out building corners offset from a reference baseline.
Locating GNSS control points at known offsets from monuments.
Frequently asked questions
How does "left" and "right" offset work?
Looking along the bearing direction, left is counterclockwise (bearing - 90°) and right is clockwise (bearing + 90°). This is standard civil engineering convention.
Can I use azimuth or do I need bearing?
This tool uses azimuth (0-360° clockwise from true north). If you have traditional bearing (N45°E format), convert first using our bearing/azimuth converter.
What about curved alignments?
For curves, the perpendicular direction is the radial direction at the current station. For preliminary computations on tangent sections, this tool is accurate. For curves use a full staking software.
How precise is the offset calculation?
Mathematical precision is exact at machine precision (~16 significant digits). Field accuracy depends on your starting point coordinate quality and bearing measurement precision.
Related tools
Pair with our staking calculator for bearing/distance output and coordinate converter for datum conversions.