DTMF Tone Generator & Decoder
Generate the touch-tone signals for any phone number, or drop in a recording to decode the dialed sequence.
Mode
Valid characters: 0-9, *, #, A-D. Anything else is ignored.
About DTMF
DTMF (Dual-Tone Multi-Frequency) is what your phone produces when you press a key — two simultaneous sine waves at specific frequencies. Telephone systems decode the pair to know which key you pressed. The pattern is universally standard: rows are 697 / 770 / 852 / 941 Hz; columns are 1209 / 1336 / 1477 / 1633 Hz.
Use the generator to type a phone number (or any sequence of 0-9, *, #, A-D), set tone duration, and render a WAV file. Use the decoder to drop in an existing recording — the tool detects each tone's row + column frequencies and reads back the dialed sequence.
How to use this DTMF tool
- 01
Pick a mode
Generator turns text into DTMF audio. Decoder turns DTMF audio into text.
- 02
Generate: type and render
Digits 0-9 plus *, #, A-D. Default 0.15 s tones with 0.05 s gaps matches the ITU-T standard.
- 03
Decode: drop a file
Drop an MP3, WAV, FLAC or any audio recording. The tool detects each tone's row + column and prints the sequence with timestamps.
Why use this DTMF tool
- Generator and decoder in one page
- ITU-T standard frequencies and timing
- Supports 0-9, *, #, A-D
- Decoder uses tuned filter banks with twist + energy thresholds
- Per-key timestamps in the decoder output
- Adjustable tone duration and inter-tone gap
- Uncompressed WAV generator output (clean for telephony testing)
- Free, private, no install
DTMF FAQ
Can it dial numbers for me?
It generates the audio. To actually dial, you'd play it into a phone receiver or feed it to a telephony system. The audio itself isn't a dialer.
What are the A-D keys?
Original 1960s DTMF spec had a 4th column with keys A-D for military and amateur radio use. Most consumer phones never had those buttons, but some radios still respond to them.
How accurate is the decoder?
Cleanly recorded tones from a real phone or this tool's generator decode reliably. Heavy line noise, music underneath, or very fast PBX-style dialing under 40 ms can cause misses. Try a quieter source if results look wrong.
Is my file kept private?
Yes. We don't analyse or index your audio.
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