About · Guide

How to plot an OS grid reference on a map

Surveyors and field teams often get locations as an Ordnance Survey grid reference or as easting and northing (British National Grid). This guide shows how to turn those values into a pin on a UK map using Grid Marks — free, in the browser, no login.

Updated August 2026 · UK (Great Britain grid)

Quick steps

1. Open gridmarks.co.uk — works on phone or desktop. No account.
2. Open Add & import in the sidebar (or use the coordinate / grid ref fields).
3. Paste your location as:
   • OS grid reference, e.g. TQ 308 805 or TQ308805
   • Easting and northing, e.g. 530800 / 180500
   • Or a full job list from Excel / CSV with a grid ref column
4. Add the mark — the pin appears on the map. Optionally set a due date, category, and notes.
5. On site: Street View, directions, share link, or download offline maps for the council area before signal drops.

What is an OS grid reference?

Great Britain uses the British National Grid (Ordnance Survey). A grid reference names a square on that grid, then fine-tunes the position with numbers. More digits mean a smaller square (more precision) — common field use is 6, 8 or 10 figures after the letters.

Examples of forms people paste into tools and spreadsheets:

• TQ 308 805 — spaced letters + easting/northing within the square
• TQ308805 — same idea without spaces
• 530800 180500 — full easting and northing in metres

Grid Marks is built for UK survey workflow: it accepts flexible grid and coordinate strings so you are not stuck reformatting every cell before mapping.

Grid reference vs easting and northing

Both describe a location on the same grid. If your spreadsheet has separate easting and northing columns, map those columns in the import wizard. If you have a single “grid ref” column, map that instead.

Plot many locations from Excel

Site lists rarely arrive one pin at a time. In Grid Marks:

1. Choose Import and upload .xlsx or .csv.
2. Match columns: name, due date, details, and location (grid ref, E/N, lat/lng or postcode).
3. Import — every valid row becomes a mark on the map.

That is usually faster than converting grid references to lat/lng in another tool first.

Offline mapping after you plot

Plotting works without a network if you already have coordinates. For a street basemap with no signal, open Offline maps, download the local authority you need, then switch to OpenStreetMap (offline) when you are on site.

Frequently asked questions

Related

• Open Grid Marks — plot a grid reference now
• Import survey jobs from Excel — whole job lists to the map
• About Grid Marks — offline maps, day plans, features
• Use cases — field visits, Excel job lists, offline mapping
• Terms of use