GPS Coordinate Precision: How Many Decimal Places Do You Need?

One of the most common questions about GPS coordinates is how many decimal places to use. The short answer: it depends on what you're doing. Here's a practical breakdown.

Decimal Degrees Precision Reference

• 1 decimal place — ±11 km. Useful only for identifying a country or large region.
• 2 decimal places — ±1.1 km. City-level precision.
• 3 decimal places — ±111 m. Neighbourhood-level; sufficient for general navigation.
• 4 decimal places — ±11 m. Street-level precision; good enough for most geocaching and hiking.
• 5 decimal places — ±1.1 m. Suitable for precision navigation and most GIS work.
• 6 decimal places — ±0.11 m. Engineering and cadastral survey grade.
• 7 decimal places — ±1 cm. The limit of most consumer GPS hardware; used in high-precision surveying.

What Consumer GPS Actually Delivers

A standard smartphone GPS is accurate to roughly 3–5 metres under open sky — about 4–5 decimal places of meaningful precision. Storing 8 decimal places from a phone GPS is false precision; the last 3 digits are essentially noise. GNSS receivers with WAAS/SBAS correction can achieve sub-metre accuracy (5–6 meaningful decimal places). RTK (Real-Time Kinematic) systems used in professional surveying achieve centimetre accuracy — all 7 decimal places are meaningful.

By Use Case

• Web maps and apps: store 6–7 decimal places in the database; display 4–5
• Navigation (hiking, driving): 4–5 decimal places is more than sufficient
• Aviation waypoints: 5 decimal places in DD or 3 decimal places of minutes in DDM
• Cadastral surveying: 6–7 decimal places
• Database geohashing: a 7-character Geohash gives ±76 m; 9-character gives ±2.4 m

Use our coordinate converter to see your coordinates expressed in all formats. Each format has its own precision conventions — our Decimal Degrees guide covers this in detail.