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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

Diffraction Limit Calculator

Calculate the smallest resolvable spot or feature that an optical system can distinguish, based on wavelength and aperture. Use it when designing cameras, telescopes, or microscopes where resolution is critical.

Wavelength (nm)

Aperture Diameter (mm)

Focal Length (mm)

Diffraction Criterion

Fill in the required fields to see your result.

Key differences

	Lens Focal Length Calculator	Diffraction Limit Calculator
Category	Optics	Optics
Inputs required	4	4
Result	Focal Length (cm)	Angular Resolution (μrad)
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 smallest resolvable spot or feature that an optical system can distinguish, based on wavelength and aperture. Use it when designing cameras, telescopes, or microscopes where resolution is critical.