Coordinate Converter

Convert latitude/longitude between Decimal Degrees (DD), Degrees-Minutes-Seconds (DMS), UTM, and MGRS formats. All calculations happen in your browser.

1.0.0
Version
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About Coordinate Converter

Coordinates leak across every tool stack with a different format — Google Maps gives you decimal degrees, a sectional aviation chart prints DMS, the survey memo your client emailed uses UTM zones, and the search-and-rescue grid that came in over the radio is MGRS. Most one-direction converters force you to pick a source, pick a target, re-paste, and lose precision through rounding errors at every step.

This coordinate converter wires all four formats — DD (decimal degrees), DMS (degrees-minutes- seconds), UTM (Universal Transverse Mercator) and MGRS (Military Grid Reference System) — into a single screen with real-time bidirectional updates: edit any field and the other three resync from the WGS84 ellipsoid math. The UTM solver uses Snyder's classical series, accurate to roughly ±10 cm inside a zone, and correctly handles the Norway/Svalbard zone exceptions (zone 32V, zones 31X–37X). MGRS is built from the proper 100 km grid-letter tables and round-trips cleanly through the latitude-band cycle. The active card highlights so you can see which format you last typed in.

Use it to translate a DMS aviation fix into a Google Maps URL, decode an MGRS distress call from a SAR net into a pin you can text someone, read a UTM grid reference off a topo map for a hiking plan, or check a survey CSV before importing it. Every conversion runs as JavaScript in the page — coordinates for a home address, a dive site, a climbing crag or a confidential survey never leave your browser. Direct links to Google Maps, OpenStreetMap and Google Earth open the location in the mapping app you actually use.

Coordinate Converter Use Cases

  • Pilots translating DMS fixes from sectional charts into Google Maps URLs
  • SAR and emergency services decoding MGRS callouts into pins to text out
  • Hikers reading UTM grid references off a paper topo map before a trip
  • Surveyors round-tripping client UTM coordinates against a WGS84 reference
  • GIS engineers sanity-checking a CSV before importing it into PostGIS or QGIS
  • Divers and climbers sharing a private site without uploading it to a server
  • Geocachers converting hint coordinates between DD, DMS and MGRS on the fly

Coordinate Converter Features

  • Four formats wired together — DD, DMS, UTM and MGRS — each updates the other three in real time as you type
  • WGS84 ellipsoid math using Snyder UTM series — round-trip accuracy of roughly ±10 cm inside a zone
  • UTM zone exceptions correctly applied for Norway (zone 32V) and Svalbard (zones 31X, 33X, 35X, 37X)
  • MGRS encoding/decoding with proper 100 km grid-letter tables and latitude-band cycle resolution
  • Five example pills (Times Square, Eiffel Tower, Sydney Opera, Beijing, Tokyo Tower) to seed inputs
  • Direct map links open the coordinate in Google Maps, OpenStreetMap and Google Earth in one click
  • All math runs as JavaScript in your browser — no coordinates uploaded, no signup, no telemetry

How to Use Coordinate Converter

Type or paste any format

Enter a decimal-degree pair in the DD card, fill the four DMS fields with degrees/minutes/seconds plus N/S and E/W, punch a UTM zone-band-easting-northing into the UTM card, or paste an MGRS string into the MGRS field.

Watch the other three formats fill in

As you type, the other three cards re-derive in real time. The card you're editing highlights blue so you can see which is the source of truth. WGS84 math means the round-trip from DD to UTM and back is lossless to ~10 cm.

Copy the format you need

Each card has a Copy button that emits a clean string — '40.758, -73.985' for DD, '40° 45' 28.8" N, 73° 59' 7.8" W' for DMS, '18 T 585628 4511322' for UTM, or '18TWL8562811322' for MGRS — ready to paste into the next app.

Open in a map

When a valid DD pair is present, three map links appear at the bottom: Google Maps, OpenStreetMap and Google Earth. Click any to see the location on a real map in a new tab — useful for sanity-checking before texting a coordinate.

Or start from an example

Five preset pills near the top (Times Square, Eiffel Tower, Sydney Opera, Beijing, Tokyo Tower) populate DD instantly so you can see what a known location looks like in every format. Useful for learning UTM zones or for demos.

Coordinate Converter FAQ

No. Every conversion — DD to DMS, UTM, MGRS and back — runs as JavaScript in the page. There is no XHR, no fetch, no background analytics call. Open DevTools, switch to the Network tab, type a coordinate and watch nothing happen. Useful when a coordinate is sensitive: a home address, a dive site, a confidential survey, a climbing crag you don't want indexed.

The UTM transform uses Snyder's classical series on the WGS84 ellipsoid. Round-trip accuracy from DD to UTM and back is roughly ±10 cm inside a single zone — well within the precision of any GPS-derived coordinate. MGRS rounds to the configured precision (default 5 digits each of easting and northing, i.e. 1 m resolution). For survey-grade geodetic transforms, the NGS NCAT tool is the gold standard.

Yes. UTM zone 32V is widened (covers Norway between 56°N and 64°N at 3°E to 12°E) and zones 31X, 33X, 35X, 37X are expanded over Svalbard (72°N to 84°N). The widely-deployed naive 'floor((lon+180)/6)+1' formula gets these wrong; this calculator applies the standard exceptions so coordinates land in the right zone.

UTM divides the world into 60 zones (6° wide) each with an easting and northing in metres, plus a latitude band letter (C–X) for hemisphere context. MGRS extends UTM with a 100 km grid square identified by two letters, then truncates easting and northing to a chosen number of digits. MGRS is more compact for radio voice — '18TWL8562811322' fits where '18 T 585628 4511322' doesn't.

UTM is mathematically undefined above 84°N and below 80°S. Those polar caps use UPS (Universal Polar Stereographic), a different projection. This converter returns blank UTM/MGRS fields when the latitude falls outside the UTM envelope so you don't get silently wrong coordinates — feed DD into a polar UPS tool instead.

In DD, use a leading minus — latitude –33.8568 is the Sydney Opera House. In DMS, set the hemisphere dropdown to S or W. In UTM, the band letter (C–M for southern, N–X for northern) carries the hemisphere; if the band is missing, the easting/northing is assumed northern, so always fill the band field for southern latitudes.

Yes. Once a valid DD pair is in the input, three deep links appear at the bottom: Google Maps (?q=lat,lon), OpenStreetMap (?mlat=...&mlon=...) and Google Earth web (@lat,lon,1000a). They open in a new tab and don't require an account. Useful for cross-checking that a translated UTM or MGRS landed on the right block.

Zero uploads. All conversions happen in your browser — no coordinates touch any server.
Try an example:

Decimal Degrees (DD) ± degrees, e.g. 40.7580, -73.9855

Degrees Minutes Seconds (DMS) 40° 45' 28.8" N, 73° 59' 7.8" W

UTM Universal Transverse Mercator — 18 T 585628 4511322

MGRS Military Grid Reference System — 18TWL8562811322

Coordinate Converter Tutorial

The Four Coordinate Formats

  • DD (Decimal Degrees) — what you see in Google Maps URLs. Simple floats. 40.7580, -73.9855
  • DMS (Degrees/Minutes/Seconds) — how old maps, aviation charts, and GPS receivers traditionally display it. 40° 45' 28.8" N
  • UTM (Universal Transverse Mercator) — used by topo maps, military, surveying. Divides the earth into 60 zones; each coord is a zone + easting + northing in meters.
  • MGRS (Military Grid Reference System) — extends UTM with a grid zone designator and 100km squares. Used by NATO militaries and SAR teams.

Common Use Cases

  • Copy a coordinate from one app into another that uses a different format
  • Convert aviation DMS charts into Google Maps DD for trip planning
  • Read military/topo UTM grid references from old paper maps
  • Share an MGRS location with rescue teams or hikers

Notes on Accuracy

UTM and MGRS use the WGS84 ellipsoid. Conversions round-trip losslessly to ~10 cm. Near the poles (above 84° N / below 80° S) UTM is undefined — use UPS (Universal Polar Stereographic) instead, which this tool does not handle.

DMS Input Tips

  • Use N/S and E/W for hemispheres
  • Negative DD lat = South; negative DD lon = West
  • DMS seconds can have decimals (e.g. 28.8")

Why In-Browser?

A coordinate can be sensitive (home address, dive site, trail crag). This tool runs entirely as JavaScript — your inputs never leave the page. Open DevTools → Network and hit submit; you won't see any requests go out.