Find the height of a location above sea level

OS Explorer Maps show contour lines at five-metre intervals. You can estimate the height of a location by:

1. locating the number set into a contour line near your location,
2. tracing the contour line around with your finger until it's close to your location and
3. counting uphill or down in multiples of five until you reach the band in which your location appears.

You can also do this online using Get-a-Map

Worked example

What is the height of The Old Rectory in East Carlton, Northamptonshire, above sea level?

Search for East Carlton by entering this place name in the search box.

Choose the one in Northamptonshire when given the choice by the pop-up window:

The page loads, showing a map at 1:50 000 scale.

Click on the symbol circled below:

The map at 1:25 000 scale loads.

Find a numbered contour (1).

Follow the line around to the vicinity (2) of your chosen point.

In this case, count up the lines until The Old Rectory (3) is above one line and below the next. It is approximately 92 metres above sea level.