OS Map Scales Explained: 1:10,000 vs 1:25,000 vs 1:50,000 vs 1:250,000

An OS map scale tells you the relationship between a distance on the map and the real distance on the ground. At 1:50,000 - the most widely used walking map scale -one centimetre on the map represents 50,000 centimetres (500 metres) in reality. The smaller the second number, the more detail the map shows. A 1:25,000 map shows twice as much detail as a 1:50,000 map; a 1:10,000 map shows five times as much.

Here is a quick reference before we go deeper:

What Does a Map Scale Actually Mean?

A map scale is expressed as a ratio: 1:50,000 means that one unit on the map equals 50,000 of the same unit on the ground. It does not matter whether you measure in centimetres, inches, or any other unit, the ratio holds.

In practical terms:

• At 1:25,000, 4 centimetres on the map = 1 kilometre on the ground
• At 1:50,000, 2 centimetres on the map = 1 kilometre on the ground
• At 1:250,000, 0.4 centimetres on the map = 1 kilometre on the ground

The larger the scale ratio (the bigger the second number), the less detail a map shows - because more real-world distance is being squeezed into each centimetre of paper.

A common point of confusion: "large scale" means more detail, not a bigger area. A 1:25,000 map is a larger scale than a 1:50,000 map even though it covers a smaller area of ground on the same sheet of paper.

1:10,000: StreetView and Urban Detail

At 1:10,000, one centimetre on the map represents just 100 metres on the ground. This is a very large scale, and at this level of detail individual buildings, car parks, field boundaries, and road widths are clearly shown.

Ordnance Survey's 1:10,000 mapping, sometimes called OS StreetView ,is the most detailed publicly available OS dataset and is primarily used for:

• Business and commercial mapping - plotting customer or prospect data at a precise local level
• Urban planning and development - site assessments, planning applications, infrastructure projects
• Postcode and boundary mapping - accurate boundaries at district and sector level require this level of detail to be drawn correctly
• GIS applications - analysts working with geospatial data typically work at 1:10,000 or larger

For most walkers and leisure users, 1:10,000 is too detailed to be practical as a navigation map, a single sheet at this scale covers only a very small area. It is the working scale of professional mapping rather than printed walking maps.

1:25,000: The Walker's Detailed Map

The 1:25,000 scale is the standard for serious walking and hill navigation in the UK. At this scale, 4 centimetres on the map equals 1 kilometre on the ground. It is the scale used by the Ordnance Survey Explorer series, the orange-covered maps familiar to anyone who has walked in the hills.

At 1:25,000, the map is detailed enough to show:

• Individual field boundaries and walls
• Footpaths and bridleways clearly distinguished
• Contour lines at 5-metre intervals (compared to 10-metre intervals at 1:50,000)
• Small streams, rocky outcrops, and summit features
• Buildings and their footprints

The closer contour spacing is particularly valuable in steep or complex terrain, on a 1:25,000 map you can distinguish a gradual slope from a cliff far more clearly than on a 1:50,000 sheet.

When to use 1:25,000: for any walk involving steep or complex terrain, mountain summits, ridge walks, scrambling routes, or any situation where precise navigation matters. The standard walking maps for Ben Nevis, Snowdon, and Scafell Pike are available at 1:25,000 scale in the UK Maps range.

The trade-off is coverage: a single A3 sheet at 1:25,000 covers roughly a 10km × 15km area, which may not be enough for a long day out. Walkers on multi-day routes often carry a 1:50,000 map for route overview alongside a 1:25,000 for detailed navigation in the trickiest sections.

1:50,000: The All-Purpose Walking and Touring Scale

1:50,000 is the most commonly used scale for walking maps in the UK and the scale of the classic Ordnance Survey Landranger series, the red-covered maps. At this scale, 2 centimetres on the map equals 1 kilometre on the ground.

A single A1 sheet at 1:50,000 can cover a large mountain and surrounding valley in one view, Ben Nevis and the surrounding Glen Nevis, for example, or all of Snowdonia's northern peaks. This balance of coverage and detail makes 1:50,000 the default scale for:

• Hill walking and day walks - where the route covers significant distance
• Long-distance route planning - the West Highland Way, Hadrian's Wall Path, and most other National Trails are most practically mapped at 1:50,000
• General touring - covering a region rather than a specific summit
• Printed large-format maps - at A1 or A0, 1:50,000 gives a comprehensive and readable overview

At 1:50,000, individual field boundaries are not shown and contour intervals are 10 metres. Small footpaths may not be shown, and some fine terrain detail is lost compared to 1:25,000. For general navigation on well-maintained trails this is not a problem; for technical off-path navigation it can be.

Almost all of the route maps in the UK Maps range - the West Highland Way, Hadrian's Wall Path, Borders Abbey Way, and St Cuthbert's Way - are produced at 1:50,000 scale.

1:250,000: Road Mapping and Route Overview

At 1:250,000, one centimetre on the map represents 2.5 kilometres on the ground. At this scale individual paths and field boundaries disappear entirely; what remains is the road network, towns and cities, rivers, and the broad shape of the landscape.

This is the scale used for road maps and driving atlases, and for the overview-level touring route maps on the UK Maps site, including the Heart 200 and South West Coastal 300.

1:250,000 is best suited to:

• Car touring and road trips - planning or navigating a multi-day driving route
• Overview planning - getting a sense of a whole region before zooming into detail
• Wall maps and display maps - showing a large geographic area at a readable size

Choosing the Right Scale

The right scale depends on two things: the purpose of the map and the area you need to cover.

For walking in the mountains, 1:25,000 gives the most detail and is the safest choice for complex terrain. 1:50,000 is fine for most well-signed trails and long-distance routes where route-finding is straightforward.

For driving or touring routes of 100 miles or more, 1:150,000 to 1:250,000 gives the right level of overview to navigate efficiently without the map becoming unwieldy.

For business mapping - postcode territories, sales areas, franchise zones - the scale depends on the size of your territory. A single sales district might be mapped at 1:100,000; a national territory overview at 1:1,000,000 or smaller.

Scale and Print Size

Scale only tells you half the story. The other variable is print size. A 1:50,000 map printed at A4 covers about a quarter of the area of the same map printed at A1. When choosing a digital download map for printing, check both the scale and the recommended print size to make sure you get the coverage and detail you need.

All maps on the UK Maps site are supplied as 300 dpi PDF files - a resolution specifically chosen to ensure the map remains sharp and readable when printed at A3, A2, A1, or larger. A map supplied at 72 dpi (typical for screen use) will print poorly at large format.

Explore OS Maps by Scale

Browse the UK Maps range of Ordnance Survey licensed PDF maps:

• Walking Maps - 1:25,000 and 1:50,000 - mountain and trail maps for walkers
• Route Maps - 1:50,000 and Road Mapping - long-distance trail and touring maps
• OS Map Tiles - 1:50,000 Geo-Referenced - for GPS devices and GIS software

All maps are produced under Ordnance Survey license (number 100048957) using up-to-date OS data.

Need a specific scale for a custom area? Get in touch about a custom map request.