Wavelength to Energy Calculator

Light travels as waves, and each wave carries energy. Our Wavelength to Energy Calculator makes it super easy to find how much energy a photon has based on its wavelength. You don’t need to be a physics expert this tool does the math for you using Planck’s equation.

We built this calculator so anyone can quickly calculate photon energy in joules (J), electronvolts (eV), or their multiples. Whether you’re a student, teacher, or science enthusiast, you’ll love how simple it is to use.

What is Wavelength to Energy in Physics?

In physics, wavelength and energy are linked by a simple idea shorter wavelengths mean higher energy. Each photon (a tiny particle of light) carries energy that depends on how “tight” the wave is.

When light’s wavelength gets smaller, its energy goes up. That’s why UV light and X-rays are more energetic than visible light.

The relationship is described by Planck’s equation, one of the most important formulas in modern physics.

The Wavelength to Energy Formula

The formula to calculate energy from wavelength is:

E = h × c / λ

Where:

• E = photon energy
• h = Planck’s constant (6.62607015 × 10⁻³⁴ J·s)
• c = speed of light (299,792,458 m/s)
• λ = wavelength in meters

This equation shows that energy is inversely proportional to wavelength. So, if you cut the wavelength in half, the energy doubles.

How to Use the Wavelength to Energy Calculator

1. Enter your wavelength value.
2. Choose the wavelength unit (like m, cm, mm, μm, nm, pm, or Å).
3. Pick your energy output unit Joules (J), electronvolts (eV), millielectronvolts (meV), kiloelectronvolts (keV), or megaelectronvolts (MeV).
4. Click Calculate.

The tool will instantly show:

• The converted wavelength in meters
• Energy in both Joules and electronvolts
• The corresponding photon frequency

That’s it! No need for a calculator or complex math.

Example Calculation

Let’s say your wavelength is 100 nm (nanometers).

Using the formula:

E = h × c / λ

E = (6.62607015 × 10⁻³⁴ × 299792458) / (100 × 10⁻⁹)

E = 1.986 × 10⁻¹⁸ J

Now, convert it to electronvolts:

1 eV = 1.602 × 10⁻¹⁹ J

E = 1.986 × 10⁻¹⁸ / 1.602 × 10⁻¹⁹ = 12.39 eV

So, a 100 nm photon carries 12.39 eV of energy.

Why This Calculator Helps

Our Wavelength to Energy Calculator is not just for scientists. It’s useful for anyone studying optics, lasers, or quantum physics. You’ll see how light energy changes with wavelength from red light to gamma rays in seconds.

It also helps students verify physics problems, engineers plan optical systems, or teachers explain light energy in class.

Final Verdict

This calculator makes the Planck equation simple and fast. It turns tricky math into instant results that anyone can understand. With clear steps, easy inputs, and accurate formulas, you’ll always get the right energy for any wavelength.

Whether you’re analyzing laser beams or studying light waves, our Wavelength to Energy Calculator is your quick science companion.

FAQs

What is the wavelength to energy formula?

It’s E = h × c / λ, where energy (E) equals Planck’s constant times the speed of light divided by the wavelength.

How do I convert wavelength to energy in eV?

Use the same formula, then divide the energy in joules by 1.602 × 10⁻¹⁹ to get the value in electronvolts.

What’s the energy of a photon with wavelength 3.5 μm?

Using the formula, E = (6.626 × 10⁻³⁴ × 299792458) / 3.5 × 10⁻⁶ = 5.67 × 10⁻²⁰ J = 0.354 eV.

What is the energy of a 100 nm photon?

A photon with 100 nm wavelength has around 12.39 eV or 1.99 × 10⁻¹⁸ J of energy.