Guides
Articles that help you get more out of our tools. Each one links straight to the tool it covers.
The Pomodoro Technique: how to make 25-minute focus work
How the Pomodoro Technique works, the rules that make it effective, the 50/10 variation and common mistakes — plus a free Pomodoro timer to start now.
How to open HEIC files and convert iPhone photos to JPG
Why iPhone HEIC photos won’t open on Windows or websites, and four ways to convert them to JPG — iPhone settings, transfer, Mac and in-browser conversion.
How to convert HWP files to PDF
What HWP and HWPX files are, how to open them without Hancom Office, and how to convert them to PDF in your browser — plus what to check in the result.
How to reduce PDF file size
Why PDFs get large and how to shrink them — removing pages, compressing in your browser and making them small from the start — plus what compression changes.
How to reduce photo file size
Shrink photos for upload and email limits — resize, lower quality and pick the right format — in order of impact, with a free in-browser compressor.
PSA, CGC, BGS and TAG grading standards compared
How the four major card grading companies score cards, and the centering each requires for a 10 — compared in one table, with a free AI grade estimate.
How to measure card centering
What trading card centering means, how to calculate the ratio, and how to photograph a card for an accurate measurement — for Pokémon, One Piece and more.
Loan repayment methods compared
Monthly payments and total interest for three repayment methods on a $100,000, 4.5%, 30-year loan — and which one fits you. Check your own numbers with the calculator.
Korean age vs international age explained
Korea’s three ways of counting age, the June 2023 switch to international age, how to calculate each one and where Korea still uses “year age”.
How to run a fair random draw and split teams
Drawing lots, ladder games, spin wheels and marble-race pickers compared — plus how to keep a draw fair, split balanced teams and keep proof of the result.