Map Tile Resolution Calculator
Web maps use the Web Mercator projection with 256-pixel tiles, where each zoom level doubles the resolution. The ground resolution, the real distance one pixel covers, depends on both the zoom level and the latitude because Mercator stretches scale toward the poles. This calculator takes the zoom level and your latitude and returns the resolution in meters per pixel, plus the approximate map scale denominator at 96 dots per inch. At zoom 0 the whole world fits in one tile, about 156,543 meters per pixel at the equator.
Tile resolution formula
Equator circumference C = 40,075,016.686 m
Equator resolution = C / (tile size * 2^zoom)
Resolution = equator resolution * cos(latitude)
Scale (1 : N) = resolution / 0.0254 * 96
The cosine of the latitude corrects the equatorial resolution for the Web Mercator scale distortion. Each zoom level doubles the number of tiles per side and halves the ground resolution.
Map tile context
- The standard slippy-map tile is 256 by 256 pixels in Web Mercator.
- Zoom 0 is one tile for the whole world; each level doubles the side count.
- Resolution shrinks toward the poles by the cosine of the latitude.
- Web Mercator uses the WGS84 equatorial radius for its sphere circumference.
- Scale denominators assume a 96 dpi screen, a common rendering convention.
Map tile resolution: frequently asked questions
What is map tile ground resolution?
Ground resolution is the real-world distance on the Earth covered by one screen pixel in a web map tile. It depends on the zoom level and the latitude, because the Web Mercator projection stretches distances toward the poles. It is usually given in meters per pixel.
How is the resolution calculated?
For the standard Web Mercator scheme with 256-pixel tiles, resolution equals the Earth circumference times the cosine of the latitude, divided by (256 times 2 to the power of the zoom level). The cosine term accounts for the projection stretch away from the equator.
Why does latitude affect resolution?
Web Mercator preserves shape but distorts scale with latitude. A pixel at the equator covers more ground than the same pixel at 60 degrees latitude. Multiplying by the cosine of the latitude corrects the equatorial resolution to your actual location.
What tile size and circumference are used?
The standard slippy-map tile is 256 by 256 pixels, and the Web Mercator equatorial circumference is 40,075,016.686 meters (based on the WGS84 semi-major axis). At zoom 0 the whole world fits in one 256-pixel tile, giving about 156,543 meters per pixel at the equator.
What is map scale at a given resolution?
Map scale relates ground distance to screen distance. The calculator also reports the approximate scale denominator assuming a 96 dots-per-inch display: scale equals resolution in meters per pixel divided by 0.0254 then times 96, which is the common screen scale convention.
Official sources
- U.S. Geological Survey: U.S. Geological Survey.
- NIST: Fundamental physical constants and units.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.