Unit-To-Unit

Guides

Plain-English guides to the units behind the converter: which one to use, why they differ and how to avoid common mistakes.

US cups to grams: flour, sugar, butter and more

Gram weights per US cup for 10 dry baking ingredients plus butter and honey, why they differ, and how to measure by volume or weight.

How much paint do I need for a room? Gallons and litres

A step-by-step method for estimating gallons or litres of paint for a room, with worked US and metric examples.

Imperial vs metric: differences and quick conversion tricks

How the metric/SI, Imperial and US Customary systems differ, who uses which, and mental shortcuts including the Fibonacci trick.

How to scale a recipe up or down: the maths and the science

Scale any recipe with a conversion factor, and learn where salt, spices, leaveners, fats, eggs and pan size need special care.

Top 20 liquid ingredients in cooking and how to measure them

The 20 most-used cooking liquids, what each one does, and how to measure liquids accurately by volume and by weight.

Liquid measuring units in recipes: volume and weight

Which units recipes use for liquids, how US, UK and metric versions differ, and grams per cup for 12 common liquids.

Airline baggage limits in kg and lb, and how to avoid fees

Typical checked and carry-on weight limits in kilograms and pounds, how overweight fees work, and practical ways to avoid them.

Metric and imperial lumber, fasteners and drill bits

Why a 2 × 4 is not 2 by 4 inches, how screw gauges, bolts and nails are sized, and how to match drill bits across inches and millimetres.

Nautical miles and knots explained

Where the nautical mile and knot come from, how they convert to km, miles and mph, and how to use them for travel time, fuel and wind.

Running pace: converting min/km to min/mile and planning race-day splits

Convert pace between min/km and min/mile, see finish times for 5K to marathon, and use race-day splits to plan your pace.

Unit conversion formulas by category

What each unit is and the formula to convert it, with exact factors for length, weight, temperature, volume, area, speed, distance and pixels.

Where unit conversions come up: travel, cooking, fitness and work

Real situations where you need to convert units, with worked examples from luggage and oven temperatures to gym plates and lumber.

Digital and print layout units: px, rem, em, points and DPI

How px, rem and em behave in CSS, how to convert pixels to points, and the difference between PPI and DPI in print.

Troy vs avoirdupois ounces: the weight of precious metals

Why a troy ounce (31.1 g) is heavier than an everyday ounce (28.35 g), which metals use which, and how mix-ups cost money.

US vs UK weights and measures: gallons, pints and tons

Why US and UK gallons, pints and tons differ, with conversion factors and the risks of confusing them.