How do you measure a ring size? We investigated the matter and found out people use completely different systems of ring sizes in various parts of the globe. One should really be careful with picking the right size when buying jewelry abroad.

What makes things even worse, the internet is full of ring size conversion tables that give wrong information and contradict to each other. It looks like many websites simply copy and paste information without trying to verify it.

We... took a different approach and researched official standards for ring sizes where we were able to find them. We came up with our ring size converter that provides precise conversion result that is based on the official standards.

Do you know what's on the picture? This small cylinder made of 90% platinum and 10% iridium worked for people in all the world since 1889. After 130 years of service on May 20th, 2019 it became retired.

This is a material prototype of kilogram, one of the 7 base metric units. Its official name is International Prototype Kilogram (IPK). It was kept in International Bureau of Weights and Measures in a special safe place near Paris.

Why the retirement? Kilogram became the ...last base SI unit that finally got rid of a material prototype. The new definition of kilogram is based on physical constants. Now any scientist can "re-create" kilogram in her own laboratory with any precession she needs. This is much more robust than relying on a physical prototype that is kept somewhere. Not to mention that no physical object is eternal and the prototype can change its characteristics over time.