UTM Zone Calculator
Find the UTM grid zone number, hemisphere band and central meridian for any longitude and latitude.
How it works
zone = ⌊(longitude + 180) / 6⌋ + 1 · central meridian = zone·6 − 183
The Universal Transverse Mercator system slices the globe into 60 north–south zones, each 6° of longitude wide, numbered 1 to 60 starting at the 180° meridian. A letter band (C–X, skipping I and O) marks 8° latitude rows. Each zone has its own projection centred on its central meridian to keep distortion low.
Worked example
Longitude −74.006°: zone = ⌊(−74.006 + 180) / 6⌋ + 1 = ⌊17.66⌋ + 1 = 18. At 40.7°N the latitude band is T, so the grid zone is 18T with central meridian 18×6 − 183 = −75°.
Frequently asked questions
Why are there 60 zones?
The 360° of longitude divided into 6°-wide strips gives 60 zones. Narrow strips keep the transverse Mercator distortion under about 0.1% within each zone.
What do the letters mean?
They are latitude bands, each 8° tall, lettered C at 80°S up to X near the poles. Letters I and O are skipped to avoid confusion with 1 and 0.
Are Norway and Svalbard special?
Yes — zones 31–37 have irregular boundaries around southwest Norway and Svalbard. This calculator uses the standard rule, which covers everywhere else.
Related calculators
Educational estimate. Uses a spherical-Earth model; results differ slightly from ellipsoidal (WGS84) calculations.