Diopter Calc
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About Diopter
Diopter was built for the moment you just need to handle this task and move on — no signup, no upload to a third-party server. Processing runs locally in your browser using modern Web APIs. Nothing is uploaded, nothing is logged, and there is no quota to worry about for casual use. Like everything else in the utility collection, it is free, ad-light, and works on mobile as well as desktop.
When you'd reach for Diopter
You need to handle a one-off task right before a meeting and don't have time to install anything.
Anyone working remotely on a borrowed or restricted machine.
Open the page, get the result, paste it into your doc — under a minute.
You're cleaning up a folder of files that accumulated over a project and need to standardize them.
Designers, writers, and developers wrapping up deliverables.
Drop each file in, copy the output, move on.
You're hitting the daily limit of a paid SaaS and need a backup option for a single quick job.
Marketers and ops people whose primary tool is metered.
Stay productive without burning credits.
You're on a public or shared machine and don't want to leave traces of what you're working on.
Travelers, contractors, anyone working from a friend's computer.
Nothing is uploaded, nothing persists if you're not signed in.
Frequently asked about Diopter
- What browsers does Diopter support?
- Every modern browser released in the last three years: Chrome, Firefox, Safari, Edge, Brave, Opera.
- Do I need to create an account to use Diopter?
- No. Diopter works without any signup. We only ask for an email if you decide to subscribe to a paid plan.
- Is Diopter really free?
- Yes — Diopter is free for unlimited personal use, with no account required and no watermark on the output.
- Are my files uploaded to a server when I use Diopter?
- Diopter processes everything in your browser using local APIs. Your files never leave your device.
- Will Diopter change my original file?
- Never. Diopter only reads your input file and produces a new output file.