Free and local: nothing leaves your computer
Upscayl
An open-source desktop app (AGPL-3.0) for Linux, macOS and Windows that runs Real-ESRGAN-family models on your GPU. Its site advertises upscaling “up to 16x”. It’s faithful rather than creative, so it sharpens and cleans up but won’t invent new texture. It’s the best default if you want unlimited free upscaling and privacy. Weak spot: faces and very small sources, where it can look painted. Source: GitHub, upscayl.org
Clarity Upscaler
An open-source (AGPL-3.0) creative upscaler built on Stable Diffusion, and described by its author as a Magnific alternative. It is the closest free route to a “hallucinated detail” look. It needs a capable NVIDIA GPU and some patience with setup. A paid hosted version exists at clarityai.co (we didn’t check its pricing). Source: GitHub
waifu2x and anime models
For line art and anime, the long-standing waifu2x family and Real-ESRGAN’s anime models remain excellent free choices. They keep flat colour areas flat. More in the anime and illustration guide.
Free in the browser
| Service | What the free tier gives you | Catch |
|---|---|---|
| Upsampler free upscaler (our product) | No sign-up, no watermark. Faithful 4× (GAN / Real-ESRGAN x4plus) and SeedVR2 models | Bigger inputs (up to 100 MP), face enhancement and larger models are paid |
| Krea | Free plan with 100 compute units a day | Upscaling on the free plan is listed as “limited”; larger upscales need a paid plan |
| Let’s Enhance | 10 free credits on sign-up, output up to 8 MP | Account needed; free output is watermarked |
Limits as stated on each service’s pricing or tool page on 14 Nov 2026: Upsampler, Krea, Let’s Enhance. Free tiers change often.
Which free option fits
- Lots of photos, privacy matters: Upscayl.
- AI art and you have a gaming GPU: Clarity, self-hosted.
- One image, right now, on a phone: a no-sign-up web tool.
- Anime screenshots or line art: waifu2x or a Real-ESRGAN anime model.
FAQ
What is the best free AI image upscaler?
For offline use, Upscayl, which is free and open source on Windows, macOS and Linux. For a creative, Magnific-style result, Clarity Upscaler if you have a capable GPU. In a browser, free web tiers such as Upsampler’s (no sign-up) or Krea’s (daily allowance) are the quickest to try.
Do free upscalers add watermarks?
Some do. Let’s Enhance watermarks free-tier output, according to its pricing page. Upscayl and Clarity run locally and add nothing. Upsampler’s free upscaler says it adds no watermark.
Is it safe to upload private photos to a free upscaler?
Read the service’s privacy policy first. If the image is sensitive, use a local tool such as Upscayl or a self-hosted Clarity, so the file never leaves your machine.