4,800 BTU/hr needed

Room volume: 960 cu ft

Radiator output: 1407 watts

Factor guide: 3 = well insulated, 5 = average, 7 = poor insulation/many windows.

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About Radiator Size

Working with this task no longer requires installing heavy desktop software — Radiator Size runs entirely in your browser, instantly. Everything happens client-side, which means your files and data never leave your machine. The interface is intentionally minimal so you can focus on the task instead of learning the tool. It is one of about a hundred utility tools that share the same philosophy: do one thing, do it well, get out of your way.

When you'd reach for Radiator Size

  • 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 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 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 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 Radiator Size

Are my files uploaded to a server when I use Radiator Size?
Radiator Size processes everything in your browser using local APIs. Your files never leave your device.
Is Radiator Size really free?
Yes — Radiator Size is free for unlimited personal use, with no account required and no watermark on the output.
Do I need to create an account to use Radiator Size?
No. Radiator Size works without any signup. We only ask for an email if you decide to subscribe to a paid plan.
Will Radiator Size change my original file?
Never. Radiator Size only reads your input file and produces a new output file.
Can I use Radiator Size commercially?
Yes. The output of Radiator Size belongs entirely to you, with no licensing restrictions.

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