Wave Speed, Frequency and Wavelength Calculator
The wave equation v = fλ and the period relation T = 1/f, from any two values.
What is Wave Calculator?
Two relationships describe a wave: v = fλ, which links speed, frequency and wavelength, and T = 1/f, which links the period to the frequency. Between them, two known quantities normally determine the other two — which is what makes a wavelength measurable from a frequency you already know.
How it works
Both equations are applied together, and which arrangement is used depends on which pair you supplied — all six valid pairs are handled explicitly. One pair is genuinely not enough: frequency and period are the same information written twice, so giving only those two leaves the speed and wavelength undetermined, and the tool says so instead of inventing a wavelength.
- Enter what you know. Every field recalculates as you type — there is no submit button. Leave the quantity you want blank and the page solves for it.
- Read the answer and the working. The result appears above the fold; underneath it is the formula with your numbers substituted, so the arithmetic can be checked rather than trusted.
- Check the units and the size. Units are shown on every value and selectable per field, so a result in kJ, kPa or km/h is converted rather than assumed. Sanity-check the magnitude against a known landmark such as 1 g/cm³ for water.
Examples
A textbook problem with a known answer
Every tool here is checked against standard example problems — the molar mass of C6H12O6 is 180.16 g/mol, and free fall from 20 m takes about 2.02 s at g = 9.8 m/s².
A result you want to reason backwards from
Leave the quantity you already know blank instead: given the final answer, most tools recover the starting value — the mass needed for a target concentration, or the height a fall must have had.
Common mistakes
Forgetting that a formula is only as good as its subscripts
H2O and H2O2 are different compounds. The formula field shows its parse — element by element — so a mis-typed subscript is visible before it reaches the arithmetic.
Mixing units in the middle of a calculation
The most common source of a wrong answer is a value in grams next to a formula expecting kilograms, or Celsius next to a gas constant expecting kelvin. This category converts on the way in and labels what it used.
Frequently asked questions
What is the wavelength of a 440 Hz note in air?
About 0.78 m at 343 m/s. λ = v ÷ f = 343 ÷ 440 — the example on this page loads those two values.
Why does frequency stay the same when light enters glass?
Because the wave arrives at a fixed rate and cannot pile up at the boundary. The speed drops in the denser medium and the wavelength shortens to compensate, keeping f constant and v = fλ true.
Why can I not enter just the frequency and the period?
Because they are reciprocals of each other, so the pair contains one piece of information rather than two. Speed and wavelength would remain undetermined — give one of them as well.