Magnetic Declination Calculator
Find the magnetic declination for any place, then set your compass the right way — adjustable bezel or non-adjustable — so map bearings and compass courses agree.
Search is the fastest way to jump worldwide. You can also click the map to set a point.
Magnetic declination
14.9° East (+14.9°)
47.60620, -122.33210
WMM2025, valid through 2029 · calculated for 2026-08-01 (UTC)
What to set on your compass
Adjustable declination compass
Set the bezel once to 14.9° East (+14.9°). After that, use map (true) bearings directly — no arithmetic on each leg. For a 120° map bearing, walk 120° on the compass after the offset is set.
Non-adjustable compass
You must convert every bearing. Declination here is 14.9° East.
- Map → compass (magnetic): subtract east declination . Example: a 120° map bearing becomes 105° on the compass (120° − 14.9°).
- Compass → map (true): add east declination . Example: a 105° compass bearing becomes 120° on the map.
Rule of thumb when east and west both matter: map→compass subtracts east / adds west; compass→map reverses that. Using the adjustable recipe on a non-adjustable compass (or the reverse) roughly doubles the error.
Why it matters
Being about 15° off compounds fast: over a few miles you can miss a trail junction or ridge by a large margin. Set the offset correctly once for your compass type.
Match your compass
Adjustable bezels get set once; non-adjustable compasses need the arithmetic on every bearing. The tool shows both paths so you never apply the wrong recipe.
Works worldwide
Search any city or place, or click the map. Values come from the World Magnetic Model (WMM2025) at sea level for the calculation date shown.
Local magnetic anomalies in some terrain can exceed the small differences between nearby points, and the model is revised on a multi-year cycle — use this as a regional setting, not a claim of per-trailhead precision.
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Frequently Asked Questions
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