What is the Microscope Magnification Calculator?
Calculate compound microscope total magnification, specimen field of view, and real specimen size from image measurements. Enter eyepiece and objective powers, optional camera relay factor, and eyepiece field number (FN). Free, private, and instant in your browser.
How to use the Microscope Magnification Calculator
- Choose what to calculate: magnification, field of view, specimen size, or lens power.
- Enter eyepiece and objective magnification (or total to solve for one lens).
- Add FN for field-of-view estimates or an image measurement for actual size.
- Read total magnification and optional digital magnification with camera factor.
- Copy the summary for lab notes or microscopy coursework.
Common use cases
- Converting a measured cell image to real micrometers at 40×
- Estimating field of view when switching from 10× to 40× objectives
- Checking total magnification with a 0.63× C-mount camera adapter
Frequently asked questions
- How is total magnification calculated?
- For a standard compound microscope, total magnification = eyepiece magnification × objective magnification. A camera adapter multiplies this further for digital images.
- What is field number (FN)?
- Field number is marked on the eyepiece (e.g. FN 20). Specimen field of view diameter ≈ FN ÷ objective magnification in millimeters.
- How do I find actual specimen size?
- Measure a feature in the image (ruler or software), then divide by total magnification to get true size at the specimen.
- Does oil immersion change magnification?
- Oil immersion affects resolution and working distance, not the labeled magnification of the objective. Use the objective marking (e.g. 100×) in calculations.
- Is my data uploaded?
- No. All calculations run locally in your browser.
