Lensmaker Equation Calculator

The Lensmaker's Equation is a fundamental formula in the field of optics, a branch of physics. This equation allows us to determine the focal length of a lens based on its physical properties and those of the surrounding medium. It is crucial to many fields, from eyeglasses manufacturing to advanced scientific research instruments.

Lensmaker Equation Calculator
Lensmaker Equation Calculator Results
Focal Length = N

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Example Formula

The Lensmaker's Equation is given as:

1/f = (nlens/nmedium - 1) × (1/R1 - 1/R2)


  1. f is the focal length of the lens.
  2. nlens is the refractive index of the lens material.
  3. nmedium is the refractive index of the surrounding medium, usually air.
  4. R1 is the radius of curvature of the first lens surface.
  5. R2 is the radius of curvature of the second lens surface.

Who wrote/refined the formula

The Lensmaker's Equation is a fundamental result in geometrical optics, derived from the principles of refraction, which were formalized by Willebrord Snellius in 1621, but the equation itself does not bear the name of a particular individual.

Real Life Application

This equation is extensively used in the design and manufacture of lenses for various applications, such as eyeglasses, camera lenses, microscopes, and telescopes. The exact parameters of the lens, such as the curvature and type of glass used, can be chosen based on the desired focal length using this equation.

Key individuals in the discipline

While the Lensmaker's Equation doesn't bear a specific name, Willebrord Snellius, also known as Snell, is a crucial figure in optics. His work on the law of refraction, or Snell's Law, was a fundamental development in understanding light behavior, which has influenced the field of optics and applications of lenses significantly.

Interesting Facts

  1. The Lensmaker's Equation plays a critical role in industries like photography and cinematography, astronomy, and scientific research, significantly impacting human understanding and artistic expression.
  2. The successful implementation of this formula in creating precise lenses has been pivotal in breakthroughs like discovering microscopic organisms or viewing distant galaxies.
  3. The Lensmaker's Equation holds true for thin lenses where the lens thickness is small compared to the radii of curvature of the surfaces. For thicker lenses, additional factors need to be considered.


Understanding the Lensmaker's Equation and the calculation of lens focal length is vital in the field of optics, a critical area in physics. This knowledge enables the design and manufacture of various types of lenses used in numerous applications, from aiding human vision to advancing scientific knowledge, and continues to be a foundational aspect of ongoing innovations in the field.

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