Coordinate Converter
Auto-detecting coordinate format converter. Paste DD, DMS, DDM, UTM, MGRS, or a Plus Code and read the same point in all six notations with a map, nearest place, elevation, and cross-links to every other tool.
The six coordinate formats
The same physical point on Earth can be written in six common notations. They disagree only in how the numbers are arranged — not in geometry. The Empire State Building's lobby door, rendered in all six:
Below the explainer is the converter itself — paste a coordinate in any of the six and pick the output format you want.
Convert your coordinate
Paste a coordinate in any of the six formats. The input format is detected automatically; pick the output format with the chip row below the input.
Output format
See it on the map
Click anywhere on the map to set the input above to that point's decimal-degree coordinates — the conversion re-runs instantly.
How to use this tool
Paste your coordinate
Drop in DD, DMS, DDM, UTM, MGRS, or a Plus Code. The format is detected automatically — no need to identify it manually.
Read the conversion
The hero card shows the canonical DD form plus a pill telling you which format was detected. Below, the FormatPanel renders the same point in all six notations with per-row copy buttons.
Click the map to convert a different point
Clicking anywhere on the map sets the input to that point in decimal degrees. The conversion re-runs instantly. "Use my location" works the same way with your browser-reported coordinate.
The six formats by family and primary specification
The Rosetta-stone block at the top of this page shows the six formats side by side; the table below groups them by family and lists the primary specification each one traces back to.
| Format | Family | Primary spec | Canonical use |
|---|---|---|---|
| DD | Angular | ISO 6709:2022 | Software, databases, APIs |
| DMS | Angular | ISO 6709:2022 | Paper maps, surveying |
| DDM | Angular | ICAO Annex 5 / IHO S-4 | Marine, aviation |
| UTM | Grid | USGS Snyder PP 1395 | Topographic mapping, GIS |
| MGRS | Grid | NGA TR 8358.1 | NATO, search-and-rescue |
| Plus Code | Alphanumeric | Google OLC spec | Address-poor regions, Google Maps |
How auto-detection works
The tool runs five tests against the input string, in priority order. Whichever matches first wins.
- Plus Code if the input contains a literal
+character and validates against Google's OLC spec. - MGRS if the input (with whitespace stripped) matches
\d{1,2}[C-HJ-NP-X][A-HJ-NP-Z][A-HJ-NP-V]\d{0,10}— the zone-band-grid-numeric pattern. - UTM if the input starts with a zone number plus band letter, followed by separate easting and northing values.
- DMS or DDMif the input contains a degree symbol or prime / second marks (°, ', ").
- DD otherwise — two numbers separated by a comma or space.
Format precision at default settings
Each format has a canonical precision — what changing the least-significant digit moves the point by. The log-scale chart below compares the eight common “default” settings across the six formats.
Practical conclusions: DD at six decimals (≈ 11 cm at the equator) is roughly equivalent to DMS at 0.01-second precision (≈ 31 cm) and UTM/MGRS at whole-metre precision. Plus Codes at the 11-character length match consumer GPS accuracy (≈ 2.8 m); the 10-character default is coarser (≈ 14 m × 14 m cell).
Why each format exists at all
The six formats arose from different domains and different eras.
DD, DMS, DDMare three notations for the same angular coordinate. DMS predates the others by centuries — historical surveys are recorded in DMS. DDM emerged in marine and aviation use because the “decimal minute” compresses well on charts. DD became the modern default with computers, where a single float is easier than three numbers.
UTM and MGRS are grid systems based on projections of the ellipsoid onto a plane. UTM was developed in the 1940s for World War II military mapping; MGRS layered a grid-letter system on top so soldiers in the field could report 4-, 6-, 8-, or 10-digit references depending on how precise they needed to be. Both have natural metres as units, which simplifies area and distance calculations.
Plus Codeswere published by Google in 2014 to address one specific problem: most of the world's population lives at addresses that postal systems don't recognise. A Plus Code is a short alphanumeric string that encodes a 14 × 14-metre cell anywhere on Earth, derivable offline, easy to share verbally.
Ten ways format conversion gets used
Anywhere a workflow crosses systems that prefer different formats, this conversion happens. The ten cases below cover the bulk of real-world use.
1. Hiking and outdoor recreation
Paper topographic maps use DMS or UTM; smartphone apps report DD. Converting between them is the first step when planning a route from a map or recording a waypoint for export.
Worked example: Half Dome summit on a USGS topographic map: 37°44'46"N, 119°31'58"W. Convert to DD for AllTrails: 37.74611, -119.53278.
2. Aviation flight planning
ICAO Annex 5 specifies degrees-decimal-minutes for flight plans and ATC reporting; modern GPS receivers report DD. Pre-flight planning crosses both formats.
Worked example: JFK threshold of runway 22L: DDM 40°38.3'N, 73°47.1'W on the flight plan; DD 40.6383, -73.7850 on the avionics.
3. Land surveying and civil engineering
Site plans, plats, and cadastral records work in UTM (or a local State Plane equivalent in the US) so distances and areas come out in metres or feet directly. Cross-jurisdictional coordination uses DD for portability.
Worked example: A development parcel surveyed at 18T 585628 mE 4511322 mN. The civil engineer converts to DD 40.7484, -73.9857 for GIS overlay.
4. Military and search-and-rescue operations
MGRS is the NATO standard for land operations — the grid-letter system lets you call out a precise location with fewer digits. Joint-operations reporting often translates to DD for interoperability with civilian air assets.
Worked example: Field SAR call: 18T WL 85628 11322. Translated to DD for the coordinating air rescue: 40.7484, -73.9857.
5. Topographic GIS workflows
ESRI / QGIS pipelines often work in UTM for area / volume computations but ingest data as DD shapefiles or DD CSV. The coordinate converter is the bridge.
Worked example: A biodiversity dataset of 400 observation points in DD gets converted to UTM Zone 18N for habitat-area analysis.
6. Marine navigation
Paper charts mark coordinates in DDM. Chartplotters use DD internally; many older receivers display DDM. Conversion happens when laying out a passage in software then exporting to the boat.
Worked example: A waypoint at the entrance to Boston Harbor: DDM 42°20.7'N, 70°54.2'W on the chart; DD 42.345, -70.9033 exported to the chartplotter.
7. Geocaching
Cache listings traditionally use DDM (Geocaching.com's default). Apps and handheld GPS may want DD or UTM. Converting between them is a routine step for a cache hunt.
Worked example: A geocache at 40°44.904'N, 73°59.142'W (Empire State Building). The cacher pastes this into the converter and gets DD for their hiking app.
8. Academic research and field observations
Ecology papers tend to report DD; archaeology more often UTM (for site grid systems). Cross-discipline meta-analyses need to harmonise formats first.
Worked example: An ecology study at -0.7395, -90.3132 (Galápagos) gets reformatted to UTM 15S 575462 mE 9918202 mN for an archaeology cross-reference.
9. Emergency services in address-poor regions
In countries where formal addresses are sparse, Plus Codes have become the de-facto location-sharing standard. Emergency dispatchers translate to DD for their CAD systems.
Worked example: A caller in Nairobi reports Plus Code 6GCRPR6Q+99. Dispatch converts to DD-1.286389, 36.817223 for the ambulance routing system.
10. Last-mile delivery routing
Plus Codes are increasingly used by delivery companies in Indonesia, India, and Nigeria where street addresses are ambiguous. The fleet-routing engine wants DD or UTM; the Plus Code is what the customer typed at checkout.
Worked example: A Jakarta delivery address arrives as 6P59WP4F+VR. The dispatcher converts to DD -6.21462, 106.84513 for the routing optimiser.
Choosing the right input
| Input shape | Right tool on Coordinately | Returns |
|---|---|---|
| Coordinate in any of the six formats (this page) | This page | The same point in all six notations |
| Address or place name | /tools/address-to-coordinates | Forward geocoding with confidence bands |
| A Google / Apple / OSM Maps URL | /tools/google-maps-coordinates | Coordinate extracted from the URL by regex |
| A ZIP / postal code | /tools/zip-to-coordinates | Centroid coordinate for the postal area |
| A click on a map | / | Click any point and read its coordinates |
Why a coordinate might fail to parse
- Mixed format / typo.
40.7484N -73.9857Wis neither pure DD nor DMS; the trailing letters look like an MGRS band. Strip the N/W and use signed numbers, or use proper DMS punctuation. - Polar UTM/MGRS. UTM covers −80° to +84° latitude. Coordinates outside that range use the UPS (Universal Polar Stereographic) system, which this tool does not yet support. Use DD for polar points.
- Plus Code without area context.Short Plus Codes (the 6-character “local” form) need a reference area to resolve. Use the full 10- or 11-character code instead.
- Old datum. The converter assumes WGS 84. If your input is in NAD 27 (US legacy) or ETRS89, the result will be offset by tens of metres. See /learn/wgs84-vs-nad83.
Privacy and data-flow notes
Coordinate parsing and conversion run entirely client-side. No service is called for the format conversion itself.
The nearest-place and elevation lookups in the report below the map hit server-side proxies (/api/geocode/reverse, /api/elevation) with Cache-Control: no-store. Browser geolocation is button-triggered only and never automatic.
Related tools
- Find lat/lon of any point on the map— The homepage finder — click any point to set its coordinates
- Extract coordinates from a maps URL— Reverse direction — paste a URL, get the lat/lon
- Drop a pin— Generate Google / Apple / OSM share URLs from a coordinate
- Focused UTM converter— Bidirectional lat/lon ↔ UTM with the zone / band breakdown
- Focused MGRS converter— Bidirectional lat/lon ↔ MGRS with the 100 km grid square
- Focused Plus Code converter— Bidirectional lat/lon ↔ Plus Code with bounding box
Related articles
- Coordinate formats explained— The pillar article — full background on all six formats
- The UTM coordinate system— Zone math, scale factor, and the polar cap exceptions
- MGRS explained— Three-layer string, NGA TR 8358.1 lettering scheme
- Decimal degrees vs DMS— The three angular notations and the 60-second carry bug
- How to read coordinates— Visual fingerprints and decoding rules for every format
Frequently asked questions
Which formats does the tool recognise?
Six: Decimal Degrees (DD), Degrees-Minutes-Seconds (DMS), Degrees-Decimal-Minutes (DDM), Universal Transverse Mercator (UTM), Military Grid Reference System (MGRS), and Plus Code (Open Location Code). The format is detected from the shape of the input string in priority order — Plus Code, MGRS, UTM, DMS/DDM, DD.
Does the tool work offline?
The format conversion itself runs entirely in your browser with no network call — yes, it works offline. The optional nearest-place and elevation lookups in the report below the map do need network, but the coordinate output renders immediately and is fully usable without those.
What datum does the converter assume?
WGS 84 — the modern global default and the datum every GPS receiver broadcasts in. If your coordinate is in NAD 27 (US legacy) or ETRS89, the result will be offset by tens of metres. Convert datum first (NGS NCAT is the canonical tool); then run through this converter.
Why does Plus Code give a slightly different point than DD?
A 10-character Plus Code describes a 14 m × 14 m cell at the equator, not a point. The tool returns the centre of that cell. For sub-metre precision, use the 11-character form, which is a 2.8 m × 2.8 m cell.
Can I enter an address instead?
For address input, use /tools/address-to-coordinates — it has live Mapbox autocomplete. Once you have a coordinate, paste it back into this converter to see all six format outputs.
What about polar coordinates (above 84°N or below 80°S)?
UTM doesn't cover the polar caps — those use the UPS (Universal Polar Stereographic) projection, which this tool doesn't yet support. For polar coordinates use DD; the other format outputs will skip UTM / MGRS or show "N/A".
Why is the auto-detection priority Plus Code → MGRS → UTM → DMS → DD?
Because the formats have increasingly permissive matchers. A Plus Code contains a literal + character — easy unambiguous detection. MGRS has a strict zone-band-grid pattern. UTM requires a leading zone-band token. DMS/DDM need degree symbols. DD is just two numbers and is the last fallback. Running the tests in that priority order avoids false positives.
How accurate is the conversion?
The formulas are implemented from primary sources to numerical precision: USGS Snyder Professional Paper 1395 for UTM, NGA TR 8358.1 for MGRS, Google's Open Location Code spec for Plus Codes. Round-trip error (DD → UTM → DD) is below 1 mm.
Sources
- ISO 6709:2022 — ISO 6709:2022 — Standard representation of geographic point location by coordinates · https://www.iso.org/standard/75147.html · Accessed .
- USGS Snyder PP 1395 — J. P. Snyder, "Map Projections — A Working Manual", USGS Professional Paper 1395 (1987) — UTM derivation · https://pubs.usgs.gov/pp/1395/report.pdf · Accessed .
- NGA TR 8358.1 — NGA Technical Report 8358.1 — The Universal Grids and the Transverse Mercator and Polar Stereographic Map Projections · https://earth-info.nga.mil/php/download.php?file=coord-utm · Accessed .
- Open Location Code specification — Google Open Location Code (Plus Code) specification · https://github.com/google/open-location-code/blob/main/docs/specification.md · Accessed .
- ICAO Annex 5 — ICAO Annex 5 — Units of Measurement to be Used in Air and Ground Operations · https://www.icao.int/Pages/default.aspx · Accessed .
- IHO S-4 — International Hydrographic Organization S-4 — Regulations of the IHO for International (INT) Charts · https://iho.int/uploads/user/pubs/standards/s-4/S-4_eEd4.9.0_EN.pdf · Accessed .
- NGS NCAT — NGS Coordinate Conversion and Transformation Tool — official US government format conversion utility · https://geodesy.noaa.gov/NCAT/ · Accessed .
- NIMA TR 8350.2 (WGS 84) — NIMA Technical Report 8350.2 — Department of Defense World Geodetic System 1984 · https://earth-info.nga.mil/php/download.php?file=coord-wgs84 · Accessed .
- W3C Geolocation API — W3C Geolocation API Level 2 — defines DD as the format browsers return · https://www.w3.org/TR/geolocation/ · Accessed .
- Mapbox Geocoding API v6 — Mapbox Geocoding v6 — used by the nearest-place lookup in the report · https://docs.mapbox.com/api/search/geocoding-v6/ · Accessed .