Last Updated: October 20, 2025
Calculate photon energy from wavelength or frequency instantly using Planck's equation with our advanced physics and quantum mechanics calculator supporting multiple units and energy conversions for spectroscopy, quantum physics, and electromagnetic radiation analysis applications.
Enter either wavelength or frequency below to calculate photon energy instantly.
Use the input fields to specify wavelength, frequency, or other parameters for accurate calculations.
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The Photon Energy Calculator is a specialized quantum mechanics tool that calculates the energy of photons using Planck's equation. Photons are fundamental particles of light and electromagnetic radiation that carry discrete amounts of energy. This calculator helps physicists, chemists, and engineers understand the quantum nature of light and electromagnetic interactions.
For more information about photon energy and quantum mechanics, visit Wikipedia: Photon and Wikipedia: Quantum Mechanics.
In quantum mechanics and modern physics, photon energy is fundamental to understanding atomic transitions, spectroscopy, photoelectric effects, and electromagnetic radiation behavior. This calculator is essential for analyzing light-matter interactions, designing optical systems, understanding laser physics, and studying the photoelectric effect that led to the development of quantum theory.
Photon energy is quantized - each photon carries a specific amount of energy determined by its frequency or wavelength.
Whether you're studying quantum mechanics, analyzing spectroscopic data, designing optical systems, or understanding the photoelectric effect, this calculator provides accurate, instant results with comprehensive unit conversions for all your quantum physics calculations. For related calculations, explore our velocity calculator, projectile motion calculator, terminal velocity calculator, trajectory calculator, and maximum height calculator.
E = hν = hc/λ
Where E = photon energy, h = Planck's constant (6.626 × 10⁻³⁴ J⋅s), ν = frequency, c = speed of light (3 × 10⁸ m/s), λ = wavelength
Planck's constant (h) is a fundamental physical constant that relates the energy of a photon to its frequency. Its value is 6.626 × 10⁻³⁴ joule-seconds. This constant is central to quantum mechanics and appears in many quantum equations, representing the quantization of energy in quantum systems.
The speed of light (c) in vacuum is approximately 3 × 10⁸ meters per second. This constant connects wavelength and frequency through the relationship c = λν, allowing us to calculate photon energy from either wavelength or frequency measurements.
Planck's constant (h): 6.626 × 10⁻³⁴ J⋅s = 4.136 × 10⁻¹⁵ eV⋅s
Speed of light (c): 2.998 × 10⁸ m/s
Electron charge (e): 1.602 × 10⁻¹⁹ C
Avogadro's number (Nₐ): 6.022 × 10²³ mol⁻¹
Photon energy is typically expressed in electron volts (eV) for atomic and molecular processes, joules (J) for macroscopic energy calculations, or kilojoules per mole (kJ/mol) for chemical applications. The choice of units depends on the specific application and scale of the problem.
Given:
Step 1: Convert wavelength to meters
λ = 500 nm = 500 × 10⁻⁹ m = 5.00 × 10⁻⁷ m
Step 2: Apply Planck's equation
E = hc/λ
E = (6.626 × 10⁻³⁴ J⋅s × 3.00 × 10⁸ m/s) / (5.00 × 10⁻⁷ m)
E = 1.988 × 10⁻²⁵ J⋅m / 5.00 × 10⁻⁷ m
E = 3.976 × 10⁻¹⁹ J
Step 3: Convert to electron volts
E = 3.976 × 10⁻¹⁹ J / 1.602 × 10⁻¹⁹ J/eV = 2.48 eV
Final Answer
2.48 eV
Energy of a green light photon
Given:
Step 1: Apply Planck's equation
E = hν
E = 6.626 × 10⁻³⁴ J⋅s × 3 × 10¹⁸ Hz
E = 1.988 × 10⁻¹⁵ J
Step 2: Convert to electron volts
E = 1.988 × 10⁻¹⁵ J / 1.602 × 10⁻¹⁹ J/eV = 12,400 eV = 12.4 keV
Step 3: Calculate wavelength
λ = c/ν = 3 × 10⁸ m/s / 3 × 10¹⁸ Hz = 1 × 10⁻¹⁰ m = 0.1 nm
Final Answer
12.4 keV
Energy of an X-ray photon
💡 Did you know? The photoelectric effect, which demonstrated that light behaves as particles (photons), was explained by Einstein using Planck's equation and earned him the Nobel Prize in Physics in 1921!
| Field/Application | Typical Energy Range | Importance |
|---|---|---|
| Solar Energy | 1.5-3.5 eV | Critical for photovoltaic cell efficiency |
| Medical Imaging | 50-150 keV | Essential for X-ray diagnostics and treatment |
| Lasers and Optics | 1-10 eV | Important for laser design and applications |
| Spectroscopy | 0.1-10 eV | Critical for chemical analysis and identification |
| Photovoltaic Cells | 1.1-3.5 eV | Essential for solar panel optimization |
| Quantum Computing | 0.01-1 eV | Important for quantum state manipulation |
| LED Technology | 1.5-4.5 eV | Critical for lighting efficiency and color |
| Research and Development | 0.001-1000 eV | Essential for scientific experiments and testing |
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