Piloting

Compass conversion

Convert a heading between true, magnetic, and compass, given variation and deviation.

Known heading

This heading is

Heading (°)

Look up variation — WMM2025

Latitude

Longitude

Date

No saved waypoints yet — save one from the distance & bearing or dead reckoning tools.

Computed variation—

World Magnetic Model 2025, valid 2025.0–2030.0. This gives variation only — deviation is specific to your vessel's compass and can't be modeled; keep entering it by hand below.

Variation & deviation

Variation

Deviation (for this heading)

East is positive, west is negative — the classic rule is "error east, compass least; error west, compass best."

Result

True—

Magnetic—

Compass—