Guides & resources
Learn the ideas behind the tools
Plain-English explainers on precious metals, measurement systems and word games — written from primary sources, and each one linked to the tool that puts it to work.
What is spot gold?
How the spot price works, what a troy ounce is, and why gold moves during the day.
Read guide Precious metalsGold vs silver
How the two metals compare as stores of value, and what the gold-to-silver ratio tells you.
Read guide ConversionsMetric vs imperial
A simple guide to the two measurement systems and the factors that connect them.
Read guide ConversionsHow many grams in an ounce?
The everyday ounce vs the troy ounce — and why gold uses a different one.
Read guide Word gamesHow to win at Scrabble
Best opening words, high-value tiles, and strategy to score more points.
Read guideHow these guides are written
Every guide starts from a question people actually ask, usually one that a calculator answers numerically without explaining anything. The point is the explanation: where a formula comes from, which convention applies, what the standard body actually says, and where the received wisdom is wrong or contested.
Definitions are taken from primary sources — the international agreements that fix the inch at 25.4 mm and the troy ounce at 31.1034768 g, the World Health Organization’s BMI bands, the WCAG contrast thresholds, current NIST password guidance. Where authorities disagree, we say so rather than quietly picking one. Market figures are described as indicative reference prices, because that is what feed data is.
Each guide links to the tool that puts it to work, and each tool page links back. If you find an error, tell us — corrections are made quickly and noted in the page’s updated date.