Coordinate Precision Calculator
The coordinate precision calculator shows how much ground distance each decimal place of precision in a latitude/longitude coordinate represents. Enter a reference latitude and a number of decimal places, and the calculator returns the north-south (latitude) precision and east-west (longitude) precision in both meters and feet. This helps you understand whether a coordinate has enough precision for your application, or how many decimal places you need to record for a given accuracy requirement.
Coordinate precision formula
One degree of latitude = pi * R / 180 meters (R = 6,371,000 m)
Lat precision (m) = (pi * R / 180) * 10^(-decimal places)
One degree of longitude = (pi * R / 180) * cos(latitude)
Lon precision (m) = (pi * R / 180) * cos(lat) * 10^(-decimal places)
Uses IUGG mean Earth radius of 6,371,000 m. Latitude precision is nearly constant; longitude precision decreases with increasing latitude due to meridian convergence.
Decimal places and accuracy reference
- 1 decimal place: ~11 km - country or region level, not useful for mapping.
- 2 decimal places: ~1.1 km - useful for neighborhood level.
- 3 decimal places: ~111 m - neighborhood or block level.
- 4 decimal places: ~11 m - typical GPS accuracy for consumer devices.
- 5 decimal places: ~1.1 m - survey-grade limit for many applications.
- 6 decimal places: ~0.11 m - precision engineering and RTK GPS.
Coordinate precision calculator: frequently asked questions
How precise is a decimal degree coordinate?
At the equator, one degree of latitude or longitude is about 111 km (69 miles). One decimal place (0.1 degree) is about 11 km. Four decimal places (0.0001 degree) is about 11 meters, which is typical GPS accuracy. Six decimal places is about 11 cm.
Why does longitude precision vary with latitude?
Lines of longitude converge at the poles. At the equator, one degree of longitude is about 111 km. At 45 degrees latitude it is about 78 km. At 60 degrees it is about 56 km. Latitude precision in the north-south direction is nearly constant at about 111 km per degree everywhere.
How many decimal places do I need for survey accuracy?
Cadastral (property boundary) surveys typically need sub-meter accuracy, requiring at least 5 decimal places in decimal degrees. GPS survey equipment (RTK) achieves centimeter accuracy, corresponding to 7-8 decimal places. Standard handheld GPS accuracy of 3-5 meters needs about 4-5 decimal places.
What is the precision of a 6-digit decimal degree coordinate?
Six decimal places in decimal degrees corresponds to approximately 0.111 meters (about 11 cm) in latitude and 0.111 * cos(latitude) meters in longitude. This is sufficient for most precision engineering and GIS applications.
How does this relate to GPS accuracy?
Commercial smartphones with GPS typically achieve 3-5 meter accuracy, equivalent to 4-5 decimal places. Survey-grade GPS (GNSS with RTK corrections) achieves 1-2 cm accuracy, equivalent to 7-8 decimal places. The coordinate display precision should match the instrument accuracy.
Official sources
- NOAA National Geodetic Survey: NGS coordinate systems and geodesy.
- USGS: USGS distance per degree reference.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.