`E = \frac{h c}{\lambda}`

Enter a value for all fields

The Photon Energy from Wavelength calculator compute the energy of a photon based on Planck's constant (h), the speed of light (c) and the wavelength of the photon ( λ).

INSTRUCTIONS: Choose units and enter the following:

• ( λ) This is the wavelength of the photon

Energy of Photon (E): The calculator returns the energy in Joules.  However, this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

The energy of a photon depends only on its wavelength.  The formula for the energy of a photon is:

          E= h•c / λ

where:

• E = energy of the photon
• h = Planck's constant 
• c = speed of light ( 2.998 × 10⁸ m/s)
• λ= wavelength of the light

Note the following relations are also true:

`f = c/λ`

`f = E/h`

`E = (h⋅c) /λ` 

`λ = (h⋅c)/E`

`E = h * f`

where:

• E = energy of light
• f = frequency
• h = Planck's Constant
• c = Speed of Light in a vacuum 

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Energy Calculators

• Kinetic Energy (change of velocity) : K = ½⋅m⋅(V₁-V₂)²
• Kinetic Energy: KE= ½⋅m⋅v²
• Relativistic Kinetic Energy
• Quantum Energy
• Potential Energy
• Potential Energy of Gravity (two bodies)
• Nuclear Binding Energy: E = m⋅c²
• Energy of a Particle in a Box
• Planck's Equation: E = h⋅f
• Molecular Kinetic Energy
• Electrostatic Potential Energy
• Photon Energy from Wavelength

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Astronomy Calculators

The Astronomy Calculator Suite includes functions that are useful for studying astronomy and include the following:

• Kepler's 3^rd Law formula                             T² = (4π • R³)/(G • M)
  • (M) - mass of the system. 
  • (T) - period of the orbit.
  • (R) - separation distance between the two objects.
  • (G) - universal gravity constant
• Small Angle Formula        Small Angle Formula    α = S / D
  • (α) - angle
  • (D) - distance to astronomical object
  • (S) - size or diameter of astronomical object
• Flux and Magnitude formulas
  • Change in Magnitude from Flux Ratio
  • Flux Ratio from Magnitudes
• Telescope formulas
  • Resolving Power of a Telescope
  • Magnification of a Telescope
• Mass formulas
  • Mass from Luminosity
  • Mass from Acceleration and Radius
  • Mass from Speed and Separation
  • Mass of extra-solar planet from mass of star, radius of star orbit and radius of exoplanet orbit
  • Mass of extra-solar planet from mass and velocity of star and velocity of planet
  • Black Hole Mass Calculator
  • Black Hole Event Horizon Calculator
• Relative Size Formulas
  • Relative Size from Relative Temperature and Luminosity
  • Relative Temperature from Relative Size and Luminosity
  • Relative Luminosity from Relative Temperature and Size
• Wavelength Formulas
  • Velocity from shift in Wavelength and Unshifted Wavelength
  • Wavelength Shift from Wavelength and Speed
  • Blackbody Wavelength from Temperature
  • Blackbody Temperature from Peak Wavelength
  • Photon Energy from Wavelength
  • Photon Wavelength from Energy
• Other Formulas
  • Distance from absolute and apparent magnitude
  • Radius from Speed and Period
  • Speed of Circular Motion
  • Hubble Time
  • Galaxy Recession Velocity
  • Luminosity from Mass
  • Hubble's Law
  • Exoplanet Calculator 
  • Orbital Radial Acceleration
  • Distance to Barycenter
  • Sakuma-Hattori Equation
  • Astronomical Distance Calculator provides the distance from the Earth to numerous astronomical bodies (e.g. Sun, Moon, planets, stars, Milky Way's Center and Edge, Andromeda Galaxy)
  • Astronomical Distance Travel Time Calculator computes the time to travel to distant parts of space at different velocities.
  • 3D Vector Calculator
  • Drake Equation Calculator
  • Seager Equation Calculator
  • Friedman Equation Calculator
  • Lagrange Points L1 and L2
  • Schwarzschild Radius
  • Hill Sphere Radius
  • Escape Velocity