How to Convert Spectral Files

Every spectrometer manufacturer uses its own proprietary file format. Bruker saves data as OPUS files, Thermo Fisher uses SPC (and SPA), JCAMP-DX is the closest thing to a universal standard, and CSV is the simplest format for data exchange. If you need to open spectra from a different instrument, share data with a collaborator, or import spectra into analysis software, you need to convert between these formats.

SpectralBench handles this conversion with no software installation and no account required — just open it in any browser. This guide walks through converting each major format.

Supported Formats

Showing 13 of 30+ supported formats. View all supported formats →

Step-by-Step: Convert Any Format to CSV

1. Open the File Converter. You will see a drag-and-drop zone.
2. Drop your file(s). SpectralBench automatically detects the format from the file header — the file extension is used as a hint but is not required.
3. Preview the spectrum. The parsed spectrum appears as an interactive plot. Verify the wavenumber/wavelength range and y-axis units look correct.
4. Download as CSV. Click the export button to save as a two-column CSV (wavenumber/wavelength, intensity). The CSV uses standard delimiters that work in Excel, Python, R, MATLAB, and any other tool.

Opening Bruker OPUS Files Without Bruker Software

OPUS files use a proprietary binary format with numbered extensions (.0, .1, .2, etc.). Traditionally, opening them required Bruker's OPUS software (Windows only, licensed). SpectralBench's Bruker OPUS reader parses the binary block structure directly in JavaScript, extracting the spectral data, instrument parameters, and sample metadata — all in your browser on any operating system.

Opening Thermo SPC Files

SPC (originally GRAMS) is a binary format used by Thermo Fisher and many other vendors. SpectralBench handles both old-format (0x4B magic byte) and new-format (0x4D) SPC files, including multi-trace files where several spectra are stored in a single container. The Spectral Viewer and Converter both accept SPC files directly.

Tips for Clean Conversions

• Check the x-axis unit. Some files store data in wavenumber (cm⁻¹), others in wavelength (nm or μm), and Raman files may use Raman shift. SpectralBench preserves the original axis — use the Unit Converter if you need to change it.
• Check the y-axis unit. FTIR files may store absorbance, transmittance, or single-beam intensity. If you need a specific representation, convert after export.
• Batch conversion. Drop multiple files at once to convert a full dataset. Each file is processed independently and can be downloaded separately.
• No install required. SpectralBench works in any modern browser — no software downloads, plugins, or accounts needed. Suitable for quick conversions on any device.

Related Resources

• File Converter — convert spectral files instantly online
• Spectral File Formats Explained — deep dive into each format's binary structure
• Spectral File Viewer — view any supported format without conversion
• Free Spectroscopy Software — other tools for working with spectral data