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How to get MGRS and UTM coordinates on your iPhone

A surveyor may ask for a grid reference instead of coordinates, and the iPhone's own apps simply don't offer one — they stick to latitude and longitude. In GeoProof, set Coordinate format to MGRS or UTM and the camera shows your grid position live; the Survey template prints MGRS, UTM and decimal side by side.

3 min read · Updated 2026-09-16

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When you need a grid reference instead of lat/long

Grid systems measure position in metres on a flat grid, which makes distances easy to read off a paper map. UTM shows up constantly in surveying, forestry, utilities and search and rescue. MGRS, built on UTM, is the one military teams and many emergency services expect. If your reader already works in one of these, decimal degrees just makes them do the conversion themselves.

How to see your current UTM or MGRS coordinates

  1. Allow location while using GeoProof, then open the Camera tab.
  2. Tap the globe pill above the shutter and choose MGRS or UTM. You can also set it in Settings under Capture > Coordinate format.
  3. Read the live value in the overlay panel. Wait until the GPS badge shows a small ± value first.
  4. For all formats at once, pick the Survey template (MGRS, UTM, decimal, altitude, accuracy and heading) or the Military template (MGRS and DMS in the green Tactical style).
  5. Take a photo, then open it: its Location data card lists Decimal, DMS, MGRS and UTM for that exact spot.

MGRS and UTM coordinates explained, with examples

These three places were run through the same formulas the app uses, so you can check you are reading the fields the right way round before you trust your own photo.

Decimal, UTM and MGRS for three locations
PlaceDecimalUTMMGRS
San Francisco Bay37.798300°, -122.377800°10N 554777 418361910SEG 5477 8361
Sydney-33.856784°, 151.215297°56S 334900 625229156HLH 3490 5229
London51.500729°, -0.124625°30N 699566 570943130UXC 9956 0943

Reading UTM

  • The number is the zone (1 to 60, each 6° of longitude wide). San Francisco is in zone 10.
  • The letter after the zone is the hemisphere: N for north, S for south. Sydney shows 56S because it is south of the equator.
  • Next comes the easting, 6 digits in metres, measured from a false origin 500,000 m west of the zone's centre line.
  • Last is the northing, 7 digits in metres from the equator (south of it, from a false origin 10,000,000 m below).

Reading MGRS

  • Zone number plus latitude band letter: 10S, 56H, 30U.
  • Two letters for the 100 km square inside that zone: EG, LH, XC.
  • Easting then northing inside the square. GeoProof shows 4 + 4 digits, which is a 10 m square.
  • The digits are cut off, not rounded, so 10SEG 5477 8361 means the 10 m square that starts 54,770 m east and 83,610 m north of the corner of the 100 km square EG.

Right, then up: easting first, northing second — the old surveyor's rhyme still works. Fewer digits means a bigger square; drop to 3 + 3 and you get 100 m instead.

Limits you should know

  • No converter: you can't type or paste coordinates to convert them. The formats are for your position and your photos.
  • UTM ignores the special zones in south-west Norway and Svalbard, and there is no UPS for polar areas. MGRS shows a dash beyond 80° S or 84° N.
  • The Apple Watch app shows decimal coordinates only, not MGRS.
  • The grid value is only as good as the phone's GPS fix. Check the ± figure before you read it out.

Questions and answers

What does the S in 56S mean in GeoProof's UTM?
Southern hemisphere. In GeoProof's UTM line the letter after the zone is N or S for the hemisphere; the MGRS line uses the latitude band letter instead.
What size of square does the MGRS reference cover?
GeoProof shows an 8-digit reference, which identifies a 10 m square. The GPS accuracy itself is shown separately as ± metres.
Can I stamp MGRS on photos?
Yes. Choose MGRS as the coordinate format or use the Survey or Military template, and the grid reference is stamped on exported photos and printed in PDF reports.
Does it need internet to show UTM?
No. All four formats are computed on the device from the GPS position.

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