About ConvertStuffNow

ConvertStuffNow is a free, browser-based unit converter that handles eight categories in one place. Enter a value, pick your units, and get the answer instantly — no sign-up, no app to download, no page reload.

What the converter covers

Length mm, cm, m, km, inches, feet, yards and miles
Weight mg, g, kg, tonnes, ounces, pounds and stone
Temperature Celsius, Fahrenheit and Kelvin
Volume ml, litres, teaspoons, tablespoons, cups, pints and gallons (US and Imperial)
Speed km/h, mph, m/s and knots
Area cm², m², km², square feet, square yards, acres and hectares
Data storage bits, bytes, KB, MB, GB and TB
Cooking teaspoons, tablespoons, cups, ml and fluid ounces

How the conversions work

Every conversion on this site uses internationally recognised factors — the same definitions used by the SI (International System of Units) and the standards bodies that govern metric and Imperial measurement globally. The inch is defined as exactly 25.4 mm. A pound is exactly 0.45359237 kg. A US gallon is exactly 3.785411784 litres. These are not approximations.

All calculations happen entirely in your browser. Nothing you type is sent to any server. There are no cookies tracking what you convert, and no data is stored between sessions. The converter works offline once the page has loaded.

Results update in real time as you type — there is no submit button and no waiting.

Why we built it

Most unit converter sites are slow to load, cluttered with ads placed in the way of the actual tool, or require more taps and page loads than the task warrants. We wanted something that felt like a proper tool — fast, clean, and designed to work well on a phone, where most of these searches actually happen.

Having eight converter categories on one page, accessible via a tab row, means you can switch from a length conversion to a temperature conversion without leaving the page or starting a new search. That sounds like a small thing, but it makes a real difference when you're mid-task in a kitchen, a gym, or a foreign city.

Who we are

ConvertStuffNow is built and maintained by Rose Venture Labs, a New Zealand-based venture builder focused on creating well-crafted, genuinely useful digital tools. We build things we'd want to use ourselves — simple, fast and honest about what they do.

The site is free because the tools cost very little to run. A small number of ads help cover hosting and ongoing maintenance. There are no premium tiers, no upsells and no accounts. If you have feedback, a bug to report or a feature suggestion, we'd like to hear from you.

How people use it

Following a recipe from another country and needing to convert cups to ml or Fahrenheit to Celsius

Checking a product's dimensions listed in inches when you're used to centimetres

Converting a running distance between kilometres and miles to compare training data

Making sense of a weather forecast abroad when the temperature is in the wrong scale

Working out why the "1 TB" drive your computer shows as 931 GB

Comparing land sizes in property listings that mix hectares and acres

Whatever the conversion, the tool is here and free to use.