🧰 Liwei Tools
AD SLOT β€” 728Γ—90 / responsive banner

Free online tools that just work

No sign-up. No tracking. Your data never leaves your browser. Pick a tool:

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Sleep Cycle Calculator

Find the best bedtime or wake-up time based on 90-minute sleep cycles.

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Pomodoro Timer

Stay focused with 25-minute work sessions and timed breaks.

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Unit Converter

Convert length, weight and temperature instantly.

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BMI Calculator

Check your Body Mass Index and healthy weight range.

AD SLOT β€” in-content responsive

Why Liwei Tools?

Every tool on this site runs 100% in your browser β€” nothing you type is sent to any server. Pages are tiny and load instantly, even on slow phones.

FAQ

Are these tools really free?

Yes. Every tool is free to use with no limits, no accounts and no paywalls. The site is supported by unobtrusive ads.

Do I need to create an account?

No. All tools work instantly β€” open the page and use it.

Is my data private?

Yes. All calculations happen locally in your browser. We never see, store or transmit what you enter.