I kept googling "chmod 755 meaning" every few months because my brain refuses to store octal. So I built the thing I wanted: type a number, tick checkboxes, or paste -rwxr-xr-x — all three stay in sync, and you get the exact chmod command to copy. It also walks you through fixing the classic "permissions are too open" SSH/AWS .pem key error (Windows icacls included). Free, no signup, no login wall. Just permissions, explained.