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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

Thin Lens Focal Length Calculator

Compute the focal length of a thin lens from object and image distances, or find where an image forms for a known lens. Essential for optics lab work, camera design, and eyeglass prescription analysis.

Object Distance (cm)

Image Distance (cm)

Fill in the required fields to see your result.

Key differences

	Lens Focal Length Calculator	Thin Lens Focal Length Calculator
Category	Optics	Optics
Inputs required	4	2
Result	Focal Length (cm)	Focal Length (cm)
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.	Compute the focal length of a thin lens from object and image distances, or find where an image forms for a known lens. Essential for optics lab work, camera design, and eyeglass prescription analysis.