Static Electricity Voltage Calculator
Estimate the voltage of a static electric discharge based on material type, humidity, and activity.
Understand why static shocks happen and how to prevent them.
Static electricity is the accumulation of electric charge on the surface of objects. It occurs when two materials with different electron affinities come into contact and then separate — a process called triboelectric charging. The resulting voltage can range from a few hundred volts (barely felt) to tens of thousands of volts (a snapping shock).
The Triboelectric Series
Materials are ranked in a series based on how readily they give up or accept electrons:
Materials at the top of the series tend to become positively charged (lose electrons) when rubbed against materials lower on the series. Materials at the bottom become negatively charged (gain electrons).
Typical Charge Build-up by Material and Activity
| Activity | Estimated Voltage (Low Humidity) |
|---|---|
| Walking on carpet (synthetic) | 35,000 V |
| Walking on vinyl flooring | 12,000 V |
| Sliding across car seat | 18,000 V |
| Working on polyurethane foam | 12,000 V |
| Picking up common plastic bag | 20,000 V |
| Walking in synthetic rubber soles | 15,000 V |
Humidity’s Critical Role
Humidity dramatically affects static buildup. At high humidity (above 60%), moisture in the air acts as a conductor, continuously draining away charge before it can accumulate. At low humidity (below 30%), charge builds up freely.
The same walk across carpet that produces 35,000 V at 10% relative humidity produces only 1,500 V at 65% humidity.
Why High Voltage Doesn’t Kill You
A 30,000 V static shock sounds terrifying, but the electric current involved is tiny — typically less than 1 milliamp (0.001 A) for less than 1 microsecond. The energy is extremely low (microjoules). It is the combination of high current AND sustained duration that kills — not voltage alone.
For comparison, household 120V AC at 100 mA for even 100 milliseconds can cause cardiac arrest.
Electrostatic Discharge (ESD) Risk to Electronics
While harmless to humans, static discharges can destroy sensitive electronics. Modern microchips can be permanently damaged by as little as 100V of ESD. This is why electronics technicians use grounding straps and anti-static mats.