Kokoro TTS wins on voice realism. It prefers a GPU with WebGPU. Piper TTS wins on speed and works on any computer. The best pick depends on your hardware and your language.
Both engines run locally in your browser. No servers, no accounts, no character limits. Your text never leaves your device.
Why local TTS is growing
Cloud TTS tools charge per character. They run costly GPU servers. The bill goes to you. A paid plan costs 6 to 99 dollars per month, and free tiers stay small.
Modern browsers changed that. They run AI models on your device. WebAssembly (WASM) runs fast code. WebGPU unlocks your graphics card.
The result is a free engine with no limits. This article compares the two best options. For more engines, see the best local TTS engines of 2026.
Kokoro TTS: the most realistic voice
Kokoro has 82 million parameters. Its voices sound almost human. It supports 8 languages and 54 voices. These include American and British English, Spanish, French, Japanese, Italian, Portuguese and Chinese. Polish is not available.
The model is about 326 MB. It downloads once. WebGPU is recommended for speed. A WASM fallback covers CPU-only machines. Kokoro is great for audiobooks, podcasts and narration.
Piper TTS: fast and CPU-friendly
Piper runs on a plain CPU. No graphics card is needed. It works on old laptops, cheap PCs and many phones.
Each voice model weighs 20 to 109 MB. Generation is fast and stable. Piper covers hundreds of voices. That includes Polish, Spanish, German and French.
Piper is the safest default. Pick it for daily work, low-end devices or any language Kokoro does not support.
Model size, speed and hardware
| Metric | Kokoro TTS | Piper TTS |
|---|---|---|
| Model size | ~326 MB | ~20-109 MB |
| Hardware | WebGPU recommended, WASM fallback | Any CPU |
| Languages | 8, no Polish | Hundreds of voices, including Polish |
| Voice quality | Ultra-realistic | Natural and clean |
| Best for | Audiobooks, video | Apps, assistants, many languages |
How to test both engines
- Open the TTS generator homepage.
- Pick Kokoro TTS from the engine list.
- Type a short sentence and click “Generate and listen”.
- Switch to Piper TTS and repeat with the same sentence.
Your ears decide faster than any benchmark. Once you pick a voice, use it for Shorts and TikTok voiceovers.
Which engine should you choose?
Choose Kokoro for realism in a supported language. It works best with WebGPU. Choose Piper for speed, compatibility and Polish.
SRT and VTT subtitles
The generator also creates subtitles. After generating speech, click "Download SRT" or "Download VTT". One sentence is one cue. SRT fits YouTube and video editors. VTT fits websites and browsers. Subtitles are created locally.
Frequently Asked Questions (FAQ)
Is Kokoro TTS really free?
Yes. It runs locally on your device with no server costs, no account and no character limits.
Does Kokoro TTS need a GPU?
WebGPU is recommended for speed. A WASM fallback lets Kokoro run on a CPU-only machine too.
Can I use Piper TTS on a phone?
Yes, if the browser supports it. Piper runs on CPU, so older phones can generate speech too.
Which engine supports Polish?
Piper. It offers Polish voices such as Gosia, Darkman and Bass. Kokoro does not support Polish.
Can I download SRT and VTT subtitles?
Yes. After generating speech, use the "Download SRT" or "Download VTT" buttons.