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Wave Interference Calculator

Find where bright fringes appear in a double-slit pattern, or the wavelength behind a measured fringe position on screen in the pattern.

y = m × λ × L ÷ d

In a double-slit pattern the bright fringes spread out with longer wavelengths, longer screens and narrower slit spacing.

Fringe order ()

Wavelength (m)

Slit to screen distance (m)

Slit separation (m)

Fringe position (m)

Fringe position

— m

The calculation runs entirely in your browser — no data leaves your device. Change any number and the answer updates instantly.