Module 9 - Compass
Variation
Variation is the angular difference between True North and Magnetic North. It changes slowly over time and varies by location. On a chart, variation is printed on the compass rose — for example: 'Var 2°W (2020)' means that Magnetic North is 2° west of True North, and this was correct in 2020.
The annual rate of change is also given (e.g., 'decreasing 8' annually'), so you can calculate the value for the charted epoch. Variation around the UK is small but changes with location and time, and it may be east or west. Never assume a nationwide value or direction: update the compass-rose value for the date and use current official chart information.
- Variation = difference between True North and Magnetic North
- Found on the chart compass rose with date and annual change
- Do not assume a UK value or direction — update the charted variation for place and date
- Apply variation to convert between True and Magnetic bearings
Continue studying Compass
This public lesson is part of Revision Module 9. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.