Field Of View (Microscope) Calculator

Work out field of view (microscope) instantly with clear inputs, formula shown and shareable results.

About Field Of View (Microscope) Calculator

Divides the eyepiece field number by the objective magnification to give the diameter of the visible field.

Formula

Field of view

Field diameter (mm) = eyepiece field number / objective magnification

Worked example

With the default values below, Field Of View (Microscope) Calculator returns Field of view diameter of 0.5000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Eyepiece field numberaccepts 5–30 mm: 20 mm
Objective magnificationaccepts 1–200: 40

Results

Field of view diameter: 0.5000 mm
Field of view diameter: 500.00 microns
Field of view area: 0.19635 mm2
10 micron cells spanning the field: 50.0

Step by step

1Values used
2Field of view
3Field of view diameter= 0.5000 mm
4Field of view diameter= 500.00 microns
5Field of view area= 0.19635 mm2
610 micron cells spanning the field= 50.0

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Where is the field number printed?

On the eyepiece barrel, often as a figure such as FN 20 or 18/20.

Does the eyepiece magnification affect the field?

No. Only the field number and the objective magnification determine the field diameter.