Voltage Drop & Cable Size Calculator
Voltage drop of a cable and the cross-section you need.
Only covers voltage drop – the cable must also be rated for the current and installation method.
Runs entirely in your browser. Nothing is sent anywhere.
How it works
- 1Enter your values.
- 2See the result update instantly as you type.
- 3Change any value to compare scenarios.
About this tool
Voltage Drop & Cable Size Calculator: Voltage drop of a cable and the cross-section you need. Type your numbers and the result is calculated instantly — no button to press, nothing to install. All math runs locally in your browser, so the values you enter are never sent anywhere.
Example
| Input | |
|---|---|
| Current (A) | 16 |
| Cable length, one way (m) | 25 |
| Cross-section (mm²) | 2.5 |
| Voltage (V) | 230 |
| System | Single-phase / DC |
| Conductor | Copper |
| Max. allowed drop (%) | 3 |
| Result | |
| Voltage drop | 5.7 V (2.48 %) |
| Minimum cross-section for the limit | 2.06 mm² |
| Next standard size | 2.5 mm² |
How do I use the Voltage Drop & Cable Size Calculator?
Enter your values. See the result update instantly as you type. Change any value to compare scenarios.
Is the Voltage Drop & Cable Size Calculator free?
Yes. It is completely free with no sign-up, no usage limits and no watermark.
Is my data sent to a server?
No. Everything is calculated locally in your browser. Nothing you enter is uploaded, logged or stored.
Does it work on my phone?
Yes. It works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux — no app needed.