How to use the microscope and telescope magnification calculator
Compute total magnification for telescopes and microscopes. Enter objective focal length, eyepiece focal length in the fields above; the telescope magnification is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- fo — Objective focal length (mm)
- fe — Eyepiece focal length (mm)
Worked example
With objective focal length = 1000 mm, eyepiece focal length = 25 mm, the calculator gives telescope magnification ≈ 40 ×.
Frequently asked questions
What is the formula for the microscope and telescope magnification calculation?
Telescope magnification (×) = fo / fe. Here fo is objective focal length (mm), fe is eyepiece focal length (mm).
What inputs do I need for the microscope and telescope magnification calculator?
You need objective focal length in mm, eyepiece focal length in mm. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.