About SparkyHub
The UK electrician's toolbox. Free calculators and references that just work.
What is SparkyHub?
SparkyHub is a collection of free tools for UK electricians. We built the calculators that sparkies actually use on the job - cable sizing, voltage drop, max Zs, fault current, and more.
Every calculation is based on BS 7671:2018+A2:2022 (the 18th Edition wiring regulations). We show the formulas and table references so you can verify the results yourself.
No sign-up. No accounts. No email capture. Just open a calculator and get your answer. That's it.
10
Free Calculators
6
Reference Tables
Why SparkyHub?
BS 7671 Compliant
All calculations verified against BS 7671:2018+A2:2022 (18th Edition). We show our working so you can verify results.
Mobile First
Designed for use on site. Large buttons, high contrast, fast loading. Works on any device without installing an app.
No Sign-Up Required
Just tools that work. No accounts, no email harvesting, no faff. Open the calculator and get your answer.
Fast & Free
No ads, no paywalls, no premium tiers. Every calculator is free to use, forever.
Who is it for?
- Qualified electricians who need quick calculations on site
- Apprentices learning the trade and studying for exams
- Contractors pricing jobs and designing installations
- Inspectors verifying calculations during EICR inspections
Accuracy & Disclaimer
We take accuracy seriously. All calculations are based on BS 7671:2018+A2:2022 and cross-referenced against the IET On-Site Guide and other authoritative sources.
However, these tools are provided for guidance only. The responsibility for any electrical installation lies with the qualified person carrying out the work. Always verify calculations independently and apply professional judgement.
Found an error? Let us know and we'll fix it. We'd rather be corrected than have sparkies using wrong values.
Ready to use the tools?
No sign-up. Just calculate.