Circuit performance
Voltage drop: route length, conductor data and preliminary checks
Use cable resistance/reactance or simplified resistivity inputs to estimate end voltage and losses.
Open voltage-drop calculator →
What this calculation is for
Voltage drop is the reduction in voltage between source and load caused by current flowing through conductor impedance. This calculator exposes its selected method and uses the route length you provide.
How to use the calculator
- Choose the system and the data method that you can substantiate.
- Enter one-way route length, current, voltage and power factor where applicable.
- Enter custom resistance/reactance or mV/A/m data, or use the clearly labelled simplified resistivity mode.
- Review percentage drop, estimated end voltage, losses and warnings.
Useful for
- • Comparing preliminary route options
- • Checking a user-supplied cable candidate
- • Estimating end voltage for a proposed load
Fields explained
One-way route length
Physical source-to-load route; the method applies any required path treatment once.
Current
The expected operating current for the assessment.
R / X or mV/A/m
Custom conductor values used by the selected method.
Parallel runs
Number of equal parallel paths; verify the installation is appropriate before relying on it.
Target drop
A user-selected design target, not an automatic code limit.
Important limits and next checks
Preliminary engineering aid only. This article and its calculator do not provide an approval, certificate, compliance determination or installation instruction.
- Use traceable conductor data at the relevant temperature and installation condition.
- Local rules, starting conditions, fault performance and equipment tolerances need separate review.
Verify applicable laws, rules, standards, manufacturer data and project conditions with a qualified electrical professional before construction, procurement or regulatory submission.