LOADBOX Jr. Voltage Drop Calculator
Input Values
Results
—
Set both voltages above to calculate
Voltage Drop
—V
Circuit Resistance
—Ω
Load Current
—mA
Power Lost
—mW
Enter your open circuit and loaded voltage readings above.
Voltage Drop Interpretation — 12V Automotive
| Voltage Drop | Circuit Resistance | Classification | Action |
|---|---|---|---|
| 0.00 – 0.10 V | 0.00 – 0.21 Ω | Excellent | No action required. Clean connections throughout. |
| 0.10 – 0.20 V | 0.21 – 0.42 Ω | Good | Acceptable. No action required. |
| 0.20 – 0.40 V | 0.42 – 0.85 Ω | Marginal | Inspect terminals, connectors, and ground points. |
| 0.40 – 0.70 V | 0.85 – 1.50 Ω | High | Corroded connector or loose terminal likely. Isolate and repair. |
| > 0.70 V | > 1.50 Ω | Excessive | Severe fault. Replace wire, connector, or ground strap. |
Note: Thresholds are for general 12V automotive circuits.