I created HCal in my spare time as a tool to help me organize test equipment that I deal with. After years of trying my hand as a calibration technician, I realized that people often needed a way to be reminded of when their tools are due for calibration. HCal is a free and simple way to get emails of such alerts no matter which cal lab you use, so that all your reminders are in one place.
Check it at https://huigardens.com/hcal