We've got both free and paid options. If you use the free version, your search data is shared to keep the library current with new materials and substances.
With a paid account, your data stays private. It's never added to the library or used for training.
We encourage free users to recommend the paid service to organizations. It keeps the site running for everyone. You can also earn a personal referral commission.
Reference library
Search FTIR & IR spectra in a daily-updated library
A 320,000+ record database built from in-house data, open datasets, user contributions, literature, patents and other authoritative sources — updated continuously to improve match success.
Free searches contribute to the public library; paid searches remain private. About the FTIR.fun Library
Image → CSV Extractor
Digitize spectrum figures from papers, reports, or screenshots into downloadable CSV curves.
Extract curve from imageNative Format Converter
Convert raw vendor files (.spa, .spc, .0, .dpt, .jdx) into CSV, JCAMP-DX, or JSON.
Convert instrument filesPeak & Group Lookup
Search characteristic wavenumbers (e.g. 1712 cm⁻¹) or functional groups with literature citations.
Look up peaks & groupsFind Reference Spectrum
Look up standard spectra directly by compound name, CAS number, formula, or spectrum ID.
Search by name or CASAI Analysis Reports
Three dedicated AI reports for specific sample questions
Submit your spectra and sample background. The analysis runs privately, never enters the public library or training data, and emails a structured PDF report with literature evidence directly to you.
Spectrum Comparison
Compare two spectra band by band (for example incoming versus qualified reference, failed versus known-good, or before versus after treatment), identify meaningful peak differences, and cite supporting literature.
Peak Assignment
Assign the absorption peaks of a sample with known composition to functional groups and bond vibrations, with traceable published DOI references for manuscripts and reports.
In-Depth Interpretation
For difficult unknowns, mixtures or degraded samples, combine library retrieval, sample context and literature evidence to propose likely components with supporting peak evidence.
FTIR.fun Local · Fully offline
A traditional IR workstation, installed in your laboratory
The fully offline edition: installed on the instrument computer and runs without any internet connection. Raw spectra, reference libraries and analysis stay on that workstation. One-time license, no subscription, no real-time updates.
Spectrum Discussion Forum
Discuss difficult spectra with administrators and the community
- IR Absorption Table
- FTIR discussion: bk-03-1-l3neu_dr._oetker_classic_muffins_1
- FTIR library search results for sample pa_66_gf_vo_a_bis_2026-11-03t09-50-36
- FTIR library search results for sample pa_66_gf_vo_a_bis_2026-11-03t09-50-36
- FTIR library search candidates for sample pa_66_gf_vo_a_bis_2026-11-03t09-50-36