Enter the wavelength of the laser (nm) and the numerical aperture into the Spatial Resolution Calculator. The calculator will evaluate the Spatial Resolution. 

Spatial Resolution Formula

The following two example problems outline the steps and information needed to calculate the Spatial Resolution.

SR = .61 * wl / NA


  • SR is the Spatial Resolution (nm)
  • wl is the wavelength of the laser (nm) 
  • NA is the numerical aperture 

To calculate the spatial resolution, multiply the wavelength by .61, then divide by the numerical aperture.

How to Calculate Spatial Resolution?

The following steps outline how to calculate the Spatial Resolution.

  1. First, determine the wavelength of the laser (nm). 
  2. Next, determine the numerical aperture. 
  3. Next, gather the formula from above = SR = .61 * wl / NA.
  4. Finally, calculate the Spatial Resolution.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

wavelength of the laser (nm) = 250

numerical aperture = .9

SR = .61 * wl / NA = ?