> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-apis/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-apis/accessing-os-apis/os-ngd-api-tiles/zoom-levels.md).

# Zoom levels

### What is a tile matrix set?

A tile matrix set is a standardised way to divide the coverage of the service into a regularly spaced grid system made up of tiles (512x512 pixels).

By defining the tile matrix set for each coordinate reference system, we can ensure interoperability across different software, achieve accurate positioning with consistent behaviour, and improve performance.

### EPSG:3857 tile matrix set

The table below shows the resolution (meters per pixel) and scale of the zoom levels within the EPSG:3857 tile matrix set.

The zoom levels start at 6 to fit in with the industry-standard initial zoom layer. This improves the interoperability of this tile matrix set with third party tools and applications.

| Zoom Level | Resolution         | Scale                 | Open or Premium |
| ---------- | ------------------ | --------------------- | --------------- |
| **6**      | 1222.9924525628201 | 4367830.1877243574709 | OpenData        |
| **7**      | 611.49622628141    | 2183915.0938621787354 | OpenData        |
| **8**      | 305.748113140705   | 1091957.5469310893677 | OpenData        |
| **9**      | 152.8740565703525  | 545978.7734655446839  | OpenData        |
| **10**     | 76.4370282851763   | 272989.3867327723419  | OpenData        |
| **11**     | 38.2185141425881   | 136494.693366386171   | OpenData        |
| **12**     | 19.1092570712941   | 68247.3466831930855   | OpenData        |
| **13**     | 9.554628535647     | 34123.6733415965427   | OpenData        |
| **14**     | 4.7773142678235    | 17061.8366707982714   | OpenData        |
| **15**     | 2.3886571339118    | 8530.9183353991357    | OpenData        |
| **16**     | 1.1943285669559    | 4265.4591676995678    | Premium data    |
| **17**     | 0.5971642834779    | 2132.7295838497839    | Premium data    |
| **18**     | 0.298582141739     | 1066.364791924892     | Premium data    |
| **19**     | 0.1492910708695    | 533.182395962446      | Premium data    |

### EPSG:27700 tile matrix set

The table below shows the resolution (meters per pixel) and scale of the zoom levels within the EPSG:27700 tile matrix set.

The zoom levels start at 0 rather than at 6 used for the EPSG:3857 tile matrix set, but the range of resolutions and scales is comparable. EPSG:27700 zoom level 0 is similar to EPSG:3857 zoom level 6.

| Zoom Level | Resolution | Scale              | Open or Premium |
| ---------- | ---------- | ------------------ | --------------- |
| **0**      | 3584       | 12799999.998       | OpenData        |
| **1**      | 1792       | 6399999.99899      | OpenData        |
| **2**      | 896        | 3199999.999496063  | OpenData        |
| **3**      | 448        | 1599999.9997480316 | OpenData        |
| **4**      | 224        | 799999.9998740158  | OpenData        |
| **5**      | 112        | 399999.9999370079  | OpenData        |
| **6**      | 56         | 199999.99996850395 | OpenData        |
| **7**      | 28         | 99999.99998425198  | OpenData        |
| **8**      | 14         | 49999.99999212599  | OpenData        |
| **9**      | 7          | 24999.999996062994 | OpenData        |
| **10**     | 3.5        | 12499.999998031497 | OpenData        |
| **11**     | 1.75       | 6249.9999990157485 | OpenData        |
| **12**     | 0.875      | 3124.9999995078742 | Premium data    |
| **13**     | 0.4375     | 1562.4999997539371 | Premium data    |
| **14**     | 0.21875    | 781.2499998769686  | Premium data    |
| **15**     | 0.109375   | 390.6249999384843  | Premium data    |


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