Practical tools for measured work
Photon energy calculator
Convert vacuum wavelength, frequency and photon energy using exact SI constants.
Calculate the layout, check the diagram, then print the result for the shop or jobsite.
How it works
E = hf = hc/λ. Planck constant h = 6.62607015 × 10⁻³⁴ J·s, vacuum light speed c = 299792458 m/s and elementary charge e = 1.602176634 × 10⁻¹⁹ C are exact SI constants. A 500 nm photon carries about 2.47968 eV.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Known photon quantity
- Vacuum wavelength
- Vacuum wavelength
- 500 nm
Primary result: Energy per photon: 3.972891714e-19 J.
Before using the result
- Check the selected mode, units and input values before using the result.
- Read the assumptions and rounding rules; compare the worked example with your intended calculation.
- A numerical result does not supply missing context or change the stated limitations.
Limitations
Wavelength is the vacuum wavelength. This is energy of one photon, not total beam energy or power. Multiply by the photon count for total energy.
Frequently asked questions
What should I verify before using this result?
Check the input values, units, dates and assumptions. Compare the method and its stated limits with the source relevant to your task.
Why might the finished result differ?
Results depend on the entered data and the model’s assumptions. Rounding, changing conditions or omitted factors can affect the comparison. Read the limitations before using the result.
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