Photon Energy from Wavelength Calculator
⚛ Atomic & Quantum. Use the Photon energy from wavelength formula to find energy, wavelength λ: pick the value you want, type the others, and the answer updates as you go.
Energy3.97 × 10⁻¹⁹ J
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Energy | J |
| Wavelength λ | nm |
Worked example
Find the energy when Wavelength λ = 500 nm.
Using E = hc/λ: Energy = 3.97 × 10⁻¹⁹ J.
Frequently asked questions
What is the formula for Photon energy from wavelength?
E = hc/λ.
What do the letters stand for, and what units are used?
Energy in J, Wavelength λ in nm.
How do you calculate energy?
Put the values into E = hc/λ. For example, with Wavelength λ = 500 nm, energy = 3.97 × 10⁻¹⁹ J.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (energy, wavelength λ) and fill in the others: it rearranges the formula for you.
