Installer tools
Small tools that show their working
The configurator, and the utilities for the jobs that sit either side of a design — quick to use on site, and transparent about how they reached an answer. Free, no account needed.
System configurator
Build a system end to end and see what actually works with what. Every pairing is checked against the compatibility graph behind the public knowledge base, so an incompatible combination is refused with a reason rather than quietly allowed.
Open the configurator →Solar PV calculator
What will this array produce in a year, and how much of it gets used on site? Headline figures from the MCS-recognised irradiance tables — the same sum a certified installer quotes — with every assumption, source and refusal explained.
Open the calculator →Battery storage calculator
Self-consumption benefit to MCS 032:2025 § 6, from occupancy, consumption and usable capacity. Produces the pre-sale disclosure table with its prescribed notes, omissions ruled by the method rather than by optimism.
Open the calculator →DC cable calculator
Size a PV string or array cable. Works out the two minima separately — current-carrying capacity after correction, and the CSA needed to hold your chosen volt-drop criterion — recommends the larger standard size, and shows every factor and source behind it.
Open the calculator →
Two ways to use any of these
The PV and battery calculators each have a plain form for people who already know what the words mean, and a walk-through — solar PV and battery storage — for people who would rather understand the answer than just receive it. They share the same figures, so you can move between them without entering anything twice.
The configurator now works the same way. Its guided version walks through why each choice narrows the next — and, like the pairs above, it carries your system with you in either direction.
Something you calculate on every job and would rather not? Tell us — this list is meant to grow.