What GaugeCalc is
The site collects the sizing arithmetic that comes up when planning a CCTV, PoE, backup-power or electrical installation: NVR and CCTV storage, camera bandwidth, PoE budget, voltage drop, battery capacity and backup, camera field of view, and electrical box fill. Each calculator page includes an explanation of how its result is calculated and a worked example. The separate guides explain the mistakes these calculations are meant to prevent.
How the calculators work
The calculators apply standard formulas, for example amps = watts ÷ volts and amp-hours = amps × hours. Each calculator page explains how its result is calculated, with a worked example, so you can check the arithmetic yourself.
Some pages list the published sources they rely on at the bottom of the page. Where a table of example values has no verified source, it is labelled as an example for planning only.
What is tested
The repository contains automated tests, run with Node.js, for three things only:
- the Electrical Box Fill Calculator's calculation engine (NEC 314.16 volume rules);
- the Field of View Calculator's results and input validation;
- the site's Content-Security-Policy header, which must match the scripts the pages contain.
The other calculators do not have automated tests. Their results come from the formulas shown on each page, so check any critical result by hand or against the manufacturer's data.
Limits of the results
- Results are estimates for planning, not a design or a code-compliance determination.
- Check the numbers against the manufacturer's datasheet for the equipment you are installing.
- Required values for safety and life-safety systems come from the applicable code and your local authority having jurisdiction, not from this site.
- Real installations vary with temperature, cable length and quality, ageing and load changes that a simple calculator does not model.
Report a mistake
If a result looks wrong, use the feedback form and include the calculator, the values you entered and what you expected. For anything else, see the contact page. This site is maintained by one person, so replies can take a little time.