Computing a US historic magnetic declination

Calculating a US historic declination value To calculate a US historic magnetic declination, you simply fill out the "Calculate Historic Declination" form under the "US Historic Declination" tab of the Magnetic Field Calculators page, then click "Calculate" at the bottom. Below is an explanation of the each of the sections contained within the calculator form.

Location Date range Result
Using the programmatic interface
Interpreting the results