🧭 Magnetic & Compass Heading
True to magnetic to compass with TVMDC
About this calculator
Compass work follows the memory aid True Virgins Make Dull Companions: start with true course, apply variation to get magnetic heading, then apply deviation to get compass heading. The rule is east is least and west is best, meaning you subtract east variation and add west variation.
Tip: find your local variation on the sectional chart compass rose. It changes slowly over the years, so check the chart date.