Speed ratio: 1.250

New CFM: 2500 (CFM ∝ RPM)

New SP: 0.781 in.wg (SP ∝ RPM²)

New HP: 1.953 HP (HP ∝ RPM³)

Fan affinity laws assume constant system and air density.

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About Fan Law

When you need this task done in seconds, Fan Law delivers a clean, focused interface without the friction of a generic tool. The goal was to keep the path from "open the page" to "get the result" as short as possible. No mandatory account, no cookie wall, no upsell at every step. 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 Fan Law

  • 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 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 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 Fan Law

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