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UtilLab

Calculators and converters that run in your browser

13 free tools for units, currency, percentages, interest, dates, age, BMI, passwords and text. No sign-up, and what you type stays on your device.

Looking for a calculator or converter?

Every tool, one index

What UtilLab is

What you can do on UtilLab

UtilLab has 13 small calculators and converters for everyday numbers, dates and text. They all follow three rules: they run on your device, they show how they reach the result, and they say where their limits are.

1

Everything runs in your browser

The unit and currency converters, the percentage, scientific, compound interest, simple interest, date, days-between-dates, age and BMI calculators, the password generator, the case converter and the word counter all work on your device. What you type is not sent to our server, and no tool needs an account. The currency converter only downloads the day's exchange rates; your amount and currencies stay in the browser.

2

Results you can check

Each calculator shows how it reaches the result: the conversion factor, the interest formula with a year-by-year breakdown, the steps of the calculation. Each tool's guide explains the formula, its limits and the most common mistakes, so you can redo the sum by hand.

3

Clear rounding, honest limits

Calculations keep full precision and only the number shown is rounded: up to 7 significant digits for units and 2 decimal places for money. When a tool simplifies reality, such as BMI ignoring muscle mass or currency results using reference rates, the page says so.

UtilLab is free to use and is paid for by ads, which may appear on its pages; ads never change a result. The site is available in English, Portuguese and Spanish and works on phones, tablets and computers, with a dark theme and keyboard search (Ctrl+K).

Frequently Asked Questions

Is UtilLab free?
Yes. Every tool is free, has no daily limit and there is no paid plan. The site is funded by ads, which may appear on its pages; they are kept apart from the tools and never change a result.
Do I need an account?
No. No tool on the site needs an account: the calculators and converters work right away, with no sign-up and nothing to install. Accounts are used only by our team and a few invited testers.
Is what I type sent anywhere?
No. The tools run in your browser, so the numbers, dates, passwords and texts you type never reach our server and are not stored by us. Your favorites, recent tools and some of your last choices are kept only in your browser. The currency converter downloads the day's rates from our server, but does not send your amount or currencies.
Which calculators and converters are there?
A unit converter, a currency converter with daily rates, a percentage calculator, a scientific calculator, compound and simple interest calculators, a date calculator, a days-between-dates counter, an age calculator, a BMI calculator, a password generator, a case converter and a word counter. They are available in English, Portuguese and Spanish.
How accurate are the results?
Unit conversions use the exact factors from international definitions, such as 1 inch = 2.54 cm, and the scientific calculator evaluates expressions with the math.js library. Results keep full precision and are rounded only when shown: up to 7 significant digits for units and 2 decimal places for money. Currency results use reference rates, so a bank or card will apply a slightly different rate.
Which languages is the site available in?
The whole site, with every tool and its guide, is available in English, Portuguese and Spanish. To switch, use the language menu at the top of the page.
Where is the text to speech tool?
Our text to speech tool has moved to SaveMeTools, our sister site, with its voices, subtitles and dialogues. The old UtilLab addresses take you there automatically. UtilLab now focuses on the 13 calculators and converters listed above.
Can I use UtilLab on my phone?
Yes. The pages adapt to any screen size and nothing needs to be installed. Tools you mark as favorites, and the ones you used recently, appear at the top of the home page on that device.