Surveying & Mapping
Bearing and Distance Calculator
Calculates straight-line distance and whole-circle survey bearing between two coordinates
Updated 28 May 2026 · Live
What this tool does
Computes the straight-line (Cartesian) distance and the whole-circle survey bearing — in decimal degrees and degrees-minutes-seconds — between two points given as eastings and northings on a consistent metric grid.
Formula Used
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How the bearing and distance calculator works
The calculator treats both points as positions on a flat metric grid. Distance is the Pythagorean straight-line between them; bearing is the whole-circle angle measured clockwise from grid north. The bearing is reported in decimal degrees and in degrees-minutes-seconds (DMS), the standard survey notation. The deltas (ΔE, ΔN) are shown so the geometry can be checked at a glance.
Bearing convention used
Whole-circle bearing (WCB) from 0° to 360°, clockwise from grid north — the convention used in UK land surveying and on Ordnance Survey mapping. North is 0°, east 90°, south 180°, west 270°. The maths uses atan2(ΔE, ΔN) — note the easting (x) argument comes first because the angle is measured from the north axis, not the east axis.
Which coordinate systems work
Any consistent metric Cartesian system: OSGB36 National Grid eastings/northings, a local site grid, or a project coordinate system. The tool does not consume latitude/longitude — those need to be projected first (for example to OSGB36 or a local Transverse Mercator zone). Over short distances on a projected grid the planar shortcut is accurate to within the grid's own scale-factor distortion; over very long distances (tens of kilometres) the projection's scale factor becomes significant and a proper geodesic distance should be used instead.
When to commission a measured survey
Boundary disputes are expensive. For plot-critical measurements — extensions across a boundary, Party Wall Act 1996 notices, easements, or any deed-plan reconciliation — an RICS-accredited land survey rather than a calculated distance from drawing scales is the appropriate basis. This calculator is a planning aid, not a measured survey.
What this tool does not do
It does not convert between latitude/longitude and grid coordinates, apply OSTN15 or scale-factor corrections, account for curvature over long distances, or output a geodetic (true) bearing. For long-range or geodetic work, use a surveying package or the OS coordinate-conversion tools rather than this planar shortcut.
Using this calculator alongside other BuildMetricLab tools
Pair the bearing and distance with our area-from-coordinates (Shoelace), GPS coordinate converter, and contour-interval tools for a small setting-out workflow. All BuildMetricLab tools run entirely in your browser — no sign-up, no data sent anywhere, and every formula is shown on-page so you can audit the maths.
Sources & methodology
ΔE = x₂ − x₁; ΔN = y₂ − y₁. Distance D = √(ΔE² + ΔN²) (Pythagoras on a metric grid). Whole-circle bearing θ = atan2(ΔE, ΔN), normalised to the 0°–360° range; reported as both decimal degrees and degrees-minutes-seconds. The deltas ΔE and ΔN are shown so the geometry can be checked. The tool assumes a consistent planar metric coordinate system (OSGB36, local site grid, or project grid); it applies no scale-factor, OSTN15, or curvature correction.
Frequently asked questions
Which bearing convention does this use?
Whole-circle bearing (WCB) from 0° to 360°, measured clockwise from grid north — the UK land-surveying convention used on Ordnance Survey mapping. The bearing is given in both decimal degrees and degrees-minutes-seconds (DMS).
Why is the distance calculated on a flat grid rather than as a great-circle?
Eastings and northings on a projected grid (OSGB36 National Grid, a local site grid, or a project grid) are already planar coordinates, so straight-line Pythagoras is the correct distance on that grid. Over very long distances the projection's own scale-factor distortion becomes significant, and a geodesic (ellipsoidal) calculation in latitude/longitude is more appropriate. For short site distances on a metric grid, the planar shortcut is accurate to within the grid's scale factor.
What coordinate system should I use?
Any consistent metric Cartesian system: OSGB36 eastings/northings, a project grid set out from a site benchmark, or a local origin. The two points must share the same coordinate system. The tool does not accept latitude/longitude — those need projecting (for example with OS coordinate-conversion utilities) before use here.
Does this replace a measured survey?
No. For boundary work, Party Wall Act 1996 notices, easements, or deed-plan reconciliation, an RICS-accredited measured survey is the appropriate basis. This calculator is a planning aid; it does not apply scale-factor corrections, OSTN15 transformations, or earth-curvature adjustments.
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