# mborgerding/kissfft

a Fast Fourier Transform (FFT) library that tries to Keep it Simple, Stupid

Repository: https://github.com/mborgerding/kissfft
Canonical: https://ross.abutalabs.com/products/kissfft
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-08-12T14:54:37+00:00

## Health v2 (maintenance only)
Score: 71/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 21, longevity 100
- inputs: {"age_days": 3234, "days_push": 21, "days_rel": 315, "gap_med": null, "n_releases_24m": 1}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1972, forks 362 (observed 2026-08-28T04:06:00.945615+00:00)

## What it is
KISS FFT is a mixed-radix Fast Fourier Transform library written in C that supports fixed-point and floating-point data types. It is designed for simplicity, easy integration into C programs, and permissive licensing rather than maximum performance.

## Use cases
- compute FFT of audio samples in C
- add a small FFT library to an embedded project
- perform real-optimized FFT for spectrum analysis
- do fast convolution FIR filtering
- generate spectrum images from signals
- use fixed-point Q15/Q31 FFT on DSP hardware

## When to choose
- you need a simple, easily embeddable FFT in C
- you need fixed-point FFT support for embedded targets
- trivial licensing matters more than peak performance
- you want multi-dimensional or real FFTs with minimal setup

## When to avoid
- you need maximum FFT performance (use FFTW or MKL)
- you need GPU-accelerated transforms
- you need highly optimized SIMD paths beyond basic SSE

## Facets
- artifact type: library
- maturity: stable
- function: math, audio-processing, image-processing
- domain: embedded-systems
- platform: cross-platform, c, cpp, embedded
- tags: fft, dsp, signal-processing, fixed-point, mixed-radix, spectrum-analysis, algorithms, audio

## Member repositories
- mborgerding/kissfft (main) score 71

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:00.945615+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:05:02.696910+00:00, confidence not recorded.
  - readme: https://github.com/mborgerding/kissfft (fetched 2026-08-28T04:06:00.945615+00:00, sha 08717cce9826)
- Data as of 2026-08-30T08:39:29.467469+00:00.