Birdwatching Calculators
Free birdwatching calculators.
Binocular specs, field of view, and optimal observation times.
Binocular Field of View Calculator
Convert between angular field of view and linear field of view at any distance. Essential for choosing birdwatching binoculars.
Binocular Magnification Calculator
Calculate exit pupil and twilight factor for any binoculars. Understand which specs matter most for birdwatching.
Dawn Chorus Time Calculator
Find the optimal birdwatching window around sunrise. The dawn chorus peaks 30 to 60 minutes before official sunrise.