What is being measured?
Wavenumber here follows the source’s spatial-frequency convention. Reciprocal wavelength and angular wavenumber differ by a factor of two pi.
Spectroscopic wavenumber is 1/wavelength. Angular wavenumber is 2π/wavelength and must not be treated as identical.
Choose a unit definition
Symbols, prefixes and conventions matter. Each row links to a definition, a worked example and a comparison table. Units of different quantities are kept separate even when symbols or dimensions look similar.
Reciprocal meters (m⁻¹)
Definition, reference values and linked conversions.
Reciprocal centimeters (cm⁻¹)
Definition, reference values and linked conversions.
Reciprocal millimeters (mm⁻¹)
Definition, reference values and linked conversions.
Reciprocal micrometers (µm⁻¹)
Definition, reference values and linked conversions.
Choose the conversion direction
Start with the unit attached to the original measurement. Select the unit needed by the receiving report, specification or formula. Conversion tools preserve the measured quantity; calculating another property can require additional measured inputs and assumptions.
Precision and common mistakes
- Keep the source and target quantity consistent. A matching symbol is not enough to establish a compatible definition.
- Record the original measurement precision. Showing twelve significant digits in a table does not make a rounded input more precise.
- Check symbol capitalization, prefixes and any regional convention in the source. Use the displayed unit definition rather than a similarly named unit.
- Factors involving repeating fractions or π use finite numerical precision. Round the final answer to the precision justified by your input.
Use a working converter
- Spectroscopic wavenumber converter
- Reciprocal centimeters to Reciprocal meters converter
- Reciprocal meters to Reciprocal centimeters converter
- Reciprocal centimeters to Reciprocal millimeters converter
- Reciprocal millimeters to Reciprocal centimeters converter
- Reciprocal centimeters to Reciprocal micrometers converter
Source and verification scope
Examples and tables are computed from the versioned unit definitions used by the linked converters. The source access dates appear below. Computandum is independent of the cited organizations; a citation does not mean that a publisher endorses this page or an actual project.