Grab a Grid Reference...
Mono version HERE

Checking tile count...
Lock zoom level of OS map  

Drag the red marker on the left map to where you want a National Grid reference*. (The blue marker on the right map cannot be dragged). The grid refs will appear on the right, and the corresponding boxes are drawn on both maps.
Please do not record wildlife using 2km, 5km or 10km grid refs as they are too vague. These are for information only.

On the left map press "Satellite" for aerial photos only, or "Map" for Google Maps only.
The right map shows Ordnance Survey (OS) maps of different scales according to the zoom amount. (OS limits the number of map tiles accessed to 100,000 per day, so the right map will stop working if this is reached).

The right map tracks the left map whenever it is zoomed, panned or the marker moves, but the right map can be can be zoomed and panned on its own. The zoom level of the right map can be locked to its current level so that it doesn't change when the left map is zoomed. Just tick the box under the OS map. (The OS zoom can still be changed manually of course).
If you've found the place you wanted using the right map, you can move the left map to it using the "Match Left Map to Right Map" button.
The "Get The Marker" button moves the marker to the centre of the left map, so match the maps first.

The "Go to ..." box can be used to go to a Grid reference (e.g. TL123456), or a postcode e.g. (MK41 9DJ), or a place name. (Currently it goes to the first matched place name, but a choice may eventually be offered - bear with me).

The "mono" map version of this tool (Google maps only) can be accessed HERE if you prefer it.

* as defined on Page 35 of A Guide to Coordinate Systems in Great Britain
(Although the National Grid covers a portion of Ireland Irish grid references are usually given using a different system. Irish grid refs can be obtained here)

This tool was created by Keith Balmer on behalf of the Bedfordshire Natural History Society.

The javascript in this application is released under the GNU General Public License Version 2.
Many thanks to Jonathan Stott for making his coordinate conversion code available!

Please email Keith Balmer if you also adopt it...