Blog - Date & time

Epoch time appears everywhere in APIs, databases, and logs, but it is easy to misread. This guide explains what epoch time means, why systems use it, and how to convert it without common mistakes.

Age in months matters more often than people think, especially for babies, forms, and milestones. This guide explains how to calculate age in months correctly and avoid common mistakes.

Calculating age sounds simple until legal forms, birthdays, leap years, and exact day counts enter the picture. This guide explains how to calculate age correctly and when the details matter.

Being born on February 29 creates age-calculation questions people rarely think about until they matter. This guide explains leap-year birthdays, legal age questions, and how to calculate age correctly.

If you know the week number but need the actual dates, the conversion is trickier than it looks — especially near year boundaries. Here's exactly how to do it in plain maths, Python, JavaScript, Excel, and SQL.

Counting working weeks between two dates isn't as simple as dividing by 7. Notice periods, project timelines, and leave calculations all depend on getting it right — here's exactly how.

Week numbers seem like a clean way to plan projects across teams and time zones. They are — until a US engineer and a European PM discover they're talking about different weeks. Here's how to use them without the traps.

Most years have 52 ISO weeks. Some have 53. That extra week happens on a predictable schedule — but it still catches payroll systems, retailers, and financial teams off guard every time.

Ask four tools what week number December 30 is, and you may get four different answers. Here's why — and how to make sure your tools agree.

ISO week numbers follow strict rules that catch most people off guard. Week 1 isn't always in January, and December 31 can fall in week 1 of the following year. Here's exactly how it works.

Calculating the number of days between two dates sounds simple — but leap years, inclusive counts, and time zones trip people up constantly. Here's how it works and when precision matters.

A Unix timestamp is a single integer that represents any moment in time — no time zones, no formatting, just a number. Here's how it works and when to use it.

January 31 plus one month should be February 31. It isn't. Here's what actually happens and why different systems disagree.