Lens Mirror Equation

Lens Mirror Equation - Perform scientific calculations with precision and accuracy.

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Updated January 2025
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Lens/Mirror Equation Calculator

1/f = 1/dₒ + 1/dᵢ

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Given Values (Enter any 2)

cm
cm

Thin Lens/Mirror Equation

This calculator uses the formula 1/f = 1/dₒ + 1/dᵢ. Sign conventions are important: converging lenses/mirrors have a positive focal length (f), while diverging ones have a negative f. Real images have a positive image distance (dᵢ), while virtual images have a negative dᵢ.