ONE FORMULA, ONE ANSWER
Thin Lens Image Distance Calculator
Check signed image distance in a paraxial thin-lens model. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Thin lens image distance d_i
Enter values and select Calculate.
d_i = 1 / (1/f − 1/d_o)
Assumptions
Use f≠0 and d_o>0. Assume a thin lens, paraxial rays and a real object. A converging lens has f>0, a diverging lens f<0 and a virtual image d_i<0. At d_o=f, no finite image distance exists.
Displayed values are floating-point approximations. Measurement uncertainty and design safety factors are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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