Decimal Degrees to DDM Converter
Signed decimal degrees to degrees and decimal minutes — hemisphere, signed or compact GPS style — with exact carry and a reverse check.
Inputs
Signed decimal degrees to degrees and decimal minutes — hemisphere, signed or compact GPS style — with exact carry and a reverse check.
Enter the values and press Calculate.
Or load an example to see a worked result.
Batch from CSV
One row per calculation, with a header row. Values use the units currently selected in the form above. Up to 10,000 rows; nothing is uploaded.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Choose one latitude/longitude, a pair, a generic angle or a CSV list.
- Enter decimal degrees as a signed number or a magnitude with N/S/E/W.
- Choose the output style — hemisphere, signed or compact marine/GPS — and 0–8 minute decimals.
- Read the DDM, the full entered value and the reverse check.
How it works
a = |DD|, D = floor(a), M = (a − D) × 60, rounded half away from zero; if M rounds to 60 the degree is increased and M becomes 0. The sign or hemisphere applies to the whole angle.
−0.5 latitude is 0° 30′ S (or −0° 30′ in signed style) — the direction survives a zero degree field. A latitude of 91 or longitude of 181 is rejected, never wrapped.
The reverse check reads the formatted result back with the DDM → DD parser; the difference is at most 0.5 × 10^−k ÷ 60 degrees.
Worked example
40.446195 and −32.5 at 4 minute decimals. 40.446195 → 40° 26.7717′ N. −32.5 → 32° 30.0000′ S. 12.999999999 carries to 13° 0.0000′. Compact: latitude −3.25 → 0315.0000S and longitude 151.2 → 15112.0000E.
Frequently asked questions
Why does 12.999999999 become 13° 0′?
At 4 decimals the minutes round to 60.0000, which carries into the degree instead of printing 60.
What is the compact format?
Marine/GPS style: two (latitude) or three (longitude) degree digits, two whole-minute digits, decimals and a hemisphere letter.
Related tools
- DDM to Decimal Degrees Converter
- DMS to Decimal Degrees Converter
- Latitude and Longitude Converter
- Latitude/Longitude Validator (Range & Format)
- Signed vs Cardinal Coordinate Notation Converter
- DDM to DMS Converter
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Cite this tool
Zerdly. (2026). Decimal Degrees to DDM Converter. Retrieved from https://www.zerdly.com/tools/dd-to-ddm-converter/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.