Zerdly

DMS to Decimal Degrees Converter

Converts one angle from degrees-minutes-seconds to decimal degrees (and DDM), with a single sign from a minus or a hemisphere letter.

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How to use this calculator

Inputs

Degrees, minutes and seconds to decimal degrees (and DDM), with one sign from a minus or a hemisphere letter.

Angle

A minus here makes the whole angle negative. Do not also choose a negative hemisphere.

More options
Output precision

0–12. 6 places ≈ 0.1 m of latitude.

Enter the values and press Convert.

Or load an example to see a worked result.

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

  1. Choose latitude, longitude or a general angle, then type degrees, minutes and seconds in the boxes or paste one formatted angle such as 40°26′46.302″N.
  2. Give the direction once: a minus on the degrees OR a hemisphere letter, never both.
  3. Press Convert to see decimal degrees, DMS, DDM and the sexagesimal breakdown; set the output decimal places under More options.

How it works

DD = sign × (degrees + minutes ÷ 60 + seconds ÷ 3600). The sign comes from either a minus or S/W, applied once to the whole value, so 0° 30′ 0″ S is −0.5°, not +0.5°.

Minutes and seconds must each be at least 0 and less than 60. Latitude is limited to 90° and longitude to 180°, checked on the unrounded value, so 90° 0′ 1″ is rejected.

The arithmetic is exact; DMS and DDM are rounded once from a single total, so a display can never read 60″. A minus with N or E is a conflict, and a minus with S or W is rejected as ambiguous rather than counted twice. No datum transformation is applied.

Worked example

40° 26′ 46.302″. 40 + 26 ÷ 60 + 46.302 ÷ 3600 = 40 + 0.433333… + 0.012861666… = 40.446195° exactly. With S instead of N, 0° 30′ 0″ S = −0.500000°.

Frequently asked questions

How does the sign combine with the hemisphere?

Use one or the other. N and E are positive, S and W negative. “−40 N” contradicts itself and is rejected, and “−12 S” is rejected as ambiguous, because some tools would count both negatives and put the point in the wrong hemisphere.

Can minutes or seconds be 60?

No. 60 minutes is the next degree and 60 seconds is the next minute, so 60 is not a valid reading. The output is rounded once from the total, so it never shows 60 either — 12° 59′ 59.9996″ at 3 decimals becomes 13° 00′ 00.000″.

Is this a coordinate transformation?

No. It only changes how one angle is written. Converting between datums or map projections (for example to GDA2020 or WGS 84) needs a separate transformation tool.

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Cite this tool

Zerdly. (2026). DMS to Decimal Degrees Converter. Retrieved from https://www.zerdly.com/tools/dms-to-decimal-degrees-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.