How powerful is lightning, in volts, amps and useful energy?
Updated · 6 min read
A typical flash carries roughly 300 million volts and about 30,000 amps, compared with 120 volts and 15 amps from a US household outlet. The power is immense but lasts only microseconds, so the total energy in a flash is far smaller than the headline numbers imply.
How many volts and amps is a lightning strike?[1]
The National Weather Service gives a typical flash as about 300 million volts and 30,000 amps. For comparison, a US household circuit runs at 120 volts and 15 amps, so the voltage is roughly two and a half million times higher.
Both numbers vary widely between flashes. Peak currents from a few thousand amps to well over 200,000 have been measured, and positive cloud-to-ground strikes tend to sit at the high end of that range while also lasting longer.
The voltage figure is the potential difference the discharge bridges, not something you could measure at a point. It reflects the charge separation the storm built up between cloud and ground before the air broke down.
Why can't lightning power a city?[1]
Because power and energy are not the same thing. A flash lasts tens of microseconds, so despite enormous instantaneous power it delivers roughly the energy of a few hundred kilowatt-hours at most, and no practical system can absorb it that fast.
Three problems stack up. The energy per flash is modest, the delivery is far too fast for any storage technology to accept, and strikes land unpredictably across a huge area rather than at a collector you built.
Capturing even one flash would need equipment rated for hundreds of thousands of amps that then sits idle for years. The economics never come close, which is why the idea stays a thought experiment despite reappearing regularly.
How much energy is actually in a flash?[1][2]
Estimates commonly land between about 1 and 5 billion joules for a full flash, which is a few hundred to a couple of thousand kilowatt-hours. Most of that leaves as heat, light and sound rather than as anything recoverable.
The duration row is the one that reframes the rest. Every other number in that table looks apocalyptic until you notice the flash is over in less time than it takes a camera shutter to open.
| Quantity | Lightning flash | Household comparison |
|---|---|---|
| Voltage | ~300,000,000 V | 120 V outlet |
| Peak current | ~30,000 A | 15 A circuit |
| Duration | Tens of microseconds | Continuous |
| Channel temperature | ~30,000 K | Oven at ~500 K |
What does that power do to electronics?[1]
It does not need a direct hit. The current in a nearby strike induces surges in wiring, phone lines and network cable, and those induced spikes destroy far more equipment than direct strikes do.
A strike hundreds of meters away can push a damaging transient into a house through the mains, the cable feed or a buried line. This is why surge protection matters on every entry path rather than just the power socket, and why a protected computer still dies through its unprotected network cable.
References
- How Powerful is Lightning?US National Weather Service, 2026
- Severe Weather 101: Lightning BasicsNOAA National Severe Storms Laboratory, 2026
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