Text to Speech Converter reads text aloud with two kinds of voices. Natural AI voices are open source neural models that run entirely inside your browser: the voice is downloaded once, then cached, and your text is never uploaded. They sound far closer to a human reader than the built in system voices, and because the audio is generated on your device, you can download the result as an MP3 or WAV file for videos, presentations, or listening on the go. Only voices trained from scratch on openly licensed recordings are offered, such as public domain LibriVox narrations and CC0 datasets, currently covering English, German, French, Dutch, Spanish, Swedish, Ukrainian, and Kazakh. Device voices use the speech engine of your own operating system and browser, which covers many more languages, including Serbian and Macedonian; in Microsoft Edge those include natural neural voices at no cost. In both modes the current sentence is highlighted while it plays, speed runs from half speed for language learners up to double speed for skimming, and you can pause, resume, or stop at any point. A session holds up to 50,000 characters, with no account and no daily quota. To check how long a piece takes to read silently, see Reading Time Calculator, and for the reverse direction, turning a recording into text, use Speech to Text Audio Transcriber.
The Natural AI voices are Piper models, an open source neural text to speech system built on the VITS architecture. Text is first converted to phonemes with the eSpeak NG phonemizer, and the neural network then turns those phonemes straight into a waveform at 22,050 samples per second. Everything runs through ONNX Runtime compiled to WebAssembly, which is why a 60MB voice can produce speech faster than real time on an ordinary laptop without any server. Voice licensing deserves more attention than it usually gets. A voice model inherits the terms of its training data, and most published Piper voices were fine-tuned from a base voice trained on a dataset licensed for research only. This tool therefore checks both the license of each voice dataset and the model it was trained from, and keeps only voices trained from scratch on recordings that allow any use. Browser text to speech is built on the Web Speech API, a standard interface that every major browser exposes as speechSynthesis. The page hands the browser a piece of text along with a voice, rate, pitch, and volume, and the browser passes it to a speech engine. On Windows that engine is the system narrator voices plus, in Edge, Microsoft neural voices; on macOS and iOS it is the Apple voice set; on Android it is the Google speech service. This is why quality varies so much by device: the same sentence can sound robotic on one machine and close to human on another. Neural voices, typically the ones labelled Natural or Online, are generated by deep learning models and handle intonation far better than the older concatenative voices that stitch together recorded fragments. Reading long text reliably needs some care. Chrome stops a single utterance after roughly fifteen seconds, so this tool splits the text into sentences and queues them one at a time, which also allows the current sentence to be highlighted. Very long sentences without punctuation are broken at word boundaries for the same reason. Speech rate in the API is a multiplier around a natural pace of about 150 words per minute, so 1.5x lands near 225 words per minute, which is close to the upper limit of comfortable comprehension for most listeners. Pitch shifts the voice up or down without changing speed. Text to speech is widely used for accessibility, for proofreading, where hearing a sentence exposes missing words that the eye skips over, and for language learning, where a slowed native voice helps with pronunciation.