Size & Reference Charts
You'll find two kinds of chart here. Shoe, clothing, ring, hat, and bra sizes follow regional conventions with no formula behind them, and brands drift from those conventions, so a US men's 10 from one maker can fit like a 10.5 from another. Use these charts to find a starting size, then check the brand's own chart, or measure yourself with our body measurement guide.
The rest have fixed answers. ISO 216 sets A4 at 210 × 297 mm, and ASTM B258 sets every AWG wire diameter. The oven and tire pressure tables show conversions you could work out yourself, laid out so you can read the number off. The baking chart lists author-reference estimates scaled from cited portions.
Clothing & Body Sizes
Bra Size Chart: US, UK, and EU/France Conversions Hat Size Chart: US, UK, and Head Circumference (cm/inches) Kids' Shoe Size Chart: US, UK, EU, and CM Men's Clothing Size Chart: US, UK, EU, and Measurements Men's Shoe Size Chart: US, UK, EU and Foot Length Ring Size Chart: US, UK, EU, and Diameter (mm) Women's Clothing Size Chart: UK, US, EU Sizes and Measurements Women's Shoe Size Chart: US, UK, EU and Foot Length