Text to Speech

Convert text to natural-sounding audio and download as MP3. Powered by OpenAI TTS.

0 / 4,000
Last updated: March 2026 ยท By - questions? Connect on LinkedIn.

This tool converts text to natural-sounding speech using the OpenAI TTS API and lets you download the result as an MP3 file. It is built for content creators, publishers, bloggers and anyone who wants to add audio to written content without recording it manually. Choose from six AI voices, adjust the playback speed, and download the finished file in seconds.

The tool uses OpenAI's tts-1 model. Your text is sent securely to OpenAI's API for processing and is not stored or used for training. There is a daily usage limit per IP address to keep the tool free and available for all users.

Frequently Asked Questions
What voices are available?
Six voices are available through the OpenAI TTS API: Alloy (neutral, versatile), Echo (male, steady), Fable (British male, expressive), Onyx (male, deep and authoritative), Nova (female, warm) and Shimmer (female, gentle). All six are natural-sounding and suitable for professional use.
What is the maximum text length?
The tool accepts up to 4,000 characters per conversion. For longer articles, split the content into sections - introduction, body, conclusion - and convert each separately, then join the MP3 files in any audio editor.
What format is the output file?
The output is an MP3 file (audio/mpeg). MP3 is compatible with all audio players, podcast platforms, video editors and web browsers. It can be uploaded directly to platforms like Spotify, Apple Podcasts or embedded in a website using an HTML audio element.
Is my text stored or used to train the AI?
No. Your text is sent to OpenAI's API to generate the audio and is not retained by this tool. JohnB.io does not log or store the content you submit. See the OpenAI Privacy Policy for full details.
What does the daily usage limit mean?
There is a per-IP daily limit to keep the tool available for everyone without requiring a login. If you hit the limit, it resets at midnight UTC. For higher-volume use, connect via LinkedIn.
How much does OpenAI TTS cost?
The tts-1 model costs $0.015 per 1,000 characters of input text. A typical 500-word article (around 3,000 characters) costs approximately $0.045 to generate. The tts-1-hd model at $0.030 per 1,000 characters offers marginally better quality for studio-grade production use.
How It Works
  1. Choose your voice and speed. Six voices are available: Alloy (neutral), Echo (male), Fable (British male), Onyx (deep male), Nova (female) and Shimmer (soft female). Speed ranges from 0.75x to 1.5x normal pace.
  2. Paste or type your text. Up to 4,000 characters per conversion. For longer content, split it into sections and convert each one separately.
  3. Click Convert to Speech. The tool sends your text to OpenAI's TTS API, which generates an MP3 audio file. This typically takes 2 to 5 seconds depending on text length.
  4. Preview and download. The audio player appears once generation is complete. Use the player to preview, then click Download MP3 to save the file to your device.
Key Points
  • Powered by OpenAI TTS. This tool uses the tts-1 model from OpenAI, which produces natural-sounding speech without robotic artefacts. It is the same model used in ChatGPT voice mode.
  • Six voice options. Each voice has a distinct character. Nova and Shimmer suit narration and editorial content. Onyx works well for podcasts and deep-read formats. Fable has a British English cadence suited to formal content.
  • MP3 output, ready to use. The downloaded file is a standard MP3 that works in any audio player, podcast host, website embed or video editor.
  • 4,000 character limit per conversion. This is the maximum input length for the OpenAI TTS API per request. A typical 500-word article section fits comfortably within this limit.
  • Free with a daily usage limit. There is no account required. A per-IP daily limit applies to keep the service available for all users. The limit resets at midnight UTC.
  • Use case - article audio. Pre-generating MP3 files for news articles or blog posts and hosting them as static files is significantly cheaper than per-read API calls, at roughly $0.015 per 1,000 characters generated.
Sources
  1. OpenAI - Text to Speech API documentation. Platform.OpenAI.com. Accessed March 2026.
  2. OpenAI API Pricing. OpenAI.com. Accessed March 2026.
  3. OpenAI TTS Model Overview. Platform.OpenAI.com. Accessed March 2026.