Pass or fail, not a bare number.
Every result is checked against the limit in your pack — NEN 1010, BS 7671, DIN VDE, NF C 15-100 or IEC typical — and the rule is cited under the number.
For electricians and installers — UK, Ireland and Europe
Does this cable pass?
Voltage drop, cable size and Iz — checked against your national limit, with the rule cited and the working shown. Offline. Pay once.
Free to use. Pro is a single €9.99 unlock. No account, no subscription.
Shows the working.
Resistance at operating temperature, the formula, every input, and the list of what was not checked. A senior can audit a junior from the phone.
Sizes the cable, both gates.
Iz after ambient, grouping and insulation factors, then voltage drop. It tells you which size was rejected and why.
Ten calculators. One job per screen.
Free is a real job. Pro is the app doing the lookup.
| Free | Pro · €9.99 once | |
|---|---|---|
| Voltage drop | Typed cross-section, custom limit, one "size up" on a FAIL, solve for max length | Find the smallest size automatically, AC and DC |
| Ampacity | Your own Iz from the book, checked against the load | Bundled tables; ambient, grouping and insulation factors; Iz bookmarks |
| Cable size | Inputs live, number locked | Two gates — Iz after factors and voltage drop — with the rejected sizes and why |
| National packs | All five | All five |
| Pipe size & loss | Required diameter and the velocity in your pipe | Catalogue pick; pressure loss with fittings |
| Heat loss | With your U-values | Construction presets and a radiator pick |
| History & share | Last 5 · share as text | Last 50 · PDF with the working · CSV export |
If you type it or pick it, it's free. If the app looks up a table or walks the sizes for you, it's Pro — €9.99, once.
A design aid, not the code book.
Here's exactly what the numbers are and what we don't check.