Tools

Two calculators, both built because we were doing the same arithmetic by hand every time we set up a camera for testing and every time a reader emailed to ask why their footage had vanished.

Neither sends anything anywhere. The maths runs in your browser, nothing is saved, and there is no sign-up.

Camera storage calculator

Tell it how many cameras, what resolution, what codec and how many days of history you want to keep. It gives you the space that takes, the smallest card that covers one camera, and how long a 2 TB or 8 TB drive lasts for the whole system. This is the single most common reason people lose the clip they needed: the card filled and looped over it three days before they went looking.

Home security scorecard

Twenty checks, weighted, adding to one hundred. The weighting is the point. A deadbolt with a long throw into a reinforced strike scores more than a doorbell camera, because one of them costs an intruder minutes at the door and the other costs them nothing at the moment they are deciding. Tick what you already have and it tells you the four things worth doing next.

Why these two

Most security advice online is a shopping list. These are not. The storage calculator will often tell you that the card you were about to buy is twice the size you need, and the scorecard puts several free habits above several expensive purchases. If a tool only ever points at a product, it is an advert wearing a lab coat.