WGS 84 → British National Grid

Latitude and longitude to British National Grid converter

Convert WGS 84 latitude and longitude to British National Grid eastings and northings individually or in batches, with coverage and OSTN15 accuracy notes.

Batch coordinate converter

Enter one WGS 84 coordinate per line as latitude, longitude.

Input example: 51.5072, -0.1276

0 of 100 coordinates

Output example: 530028, 180380

Numeric coordinates are rounded for display: decimal latitude/longitude to up to 6 decimal places, metre-based coordinates to up to 3, DMS seconds to up to 2, and DDM minutes to up to 4.

About this conversion

Convert WGS 84 positions to British National Grid (EPSG:27700) eastings and northings using the high-accuracy OSTN15 transformation for Great Britain.

Frequently asked questions

What input is accepted?

By default, enter WGS 84 latitude first and longitude second in decimal degrees. Select Reverse coordinate order to enter longitude first. Latitude must be from −90 to 90 and longitude from −180 to 180.

What output will I receive?

The result contains EPSG:27700 easting and northing in metres. It does not add the two-letter square used by a formatted OS Grid Reference.

Which axes and units are used?

WGS 84 input defaults to latitude then longitude in degrees. British National Grid output uses easting then northing in metres.

How are precision and datum handled?

The conversion requires OSTN15 and does not fall back to a lower-accuracy transformation. Result quality is still limited by the accuracy of the source coordinate.

Where can I use this coordinate system?

British National Grid is for Great Britain. Locations outside its valid transformation area are rejected rather than extrapolated.

What should I check?

  • Check that the selected latitude/longitude order matches each input row.
  • Use coordinates within the British National Grid transformation area in Great Britain.
  • Expect numeric eastings and northings rather than a two-letter OS Grid Reference.

Is the output an OS Grid Reference?

No. This route returns full numeric eastings and northings in EPSG:27700.

Why is OSTN15 required?

It provides the high-accuracy transformation between WGS 84 and the national grid.