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Both calculators run independently — change the inputs on either side to compare results.

Lens Focal Length Calculator

Compute the focal length of any thick or thin lens from its refractive index, surface curvatures, and center thickness using the lensmaker's equation. Essential for optical designers, physics students, and DIY telescope builders.

Refractive Index of Lens Material

Radius of First Surface (cm)

Radius of Second Surface (cm)

Lens Thickness (cm)

Fill in the required fields to see your result.

Optics

Numerical Aperture Calculator

Calculate the numerical aperture (NA) of an optical fiber from the refractive indices of its core and cladding. NA determines light-gathering ability and the maximum acceptance angle of the fiber.

Core Refractive Index

Cladding Refractive Index

Fill in the required fields to see your result.

Key differences

	Lens Focal Length Calculator	Numerical Aperture Calculator
Category	Optics	Optics
Inputs required	4	2
Result	Focal Length (cm)	Numerical Aperture
What it does	Compute the focal length of any thick or thin lens from its refractive index, surface curvatures, and center thickness using the lensmaker's equation. Essential for optical designers, physics students, and DIY telescope builders.	Calculate the numerical aperture (NA) of an optical fiber from the refractive indices of its core and cladding. NA determines light-gathering ability and the maximum acceptance angle of the fiber.