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Amperage Calculator

Convert a load in watts and a supply voltage into the current drawn in amps.

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Need Current? The Amperage Calculator derives it from Power (W), Voltage (V) in one step. For instance, with Power (W) = 2,000 and Voltage (V) = 230 it returns Current = 8.696 A.

How to use it

  1. Enter your values: Power (W), Voltage (V).
  2. Read the result instantly: Current.

Frequently asked questions

What does the Amperage Calculator actually compute?

It takes Power (W) and Voltage (V) and derives Current from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

2 values: Power (W) and Voltage (V). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Power (W) = 2,000 and Voltage (V) = 230, the calculator returns Current = 8.696 A. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

When would I actually use this?

Putting a number on a bill: what an appliance costs to run, whether a solar array covers the load, and how much heating a room actually needs.

What is the most common mistake?

Confusing power with energy. A kilowatt is a rate and a kilowatt-hour is a quantity; a 2 kW heater on for half an hour uses 1 kWh, and only the second figure appears on a bill.

How accurate is it, and what are the limits?

For guidance only. Consult a qualified electrician before wiring or sizing circuit protection.

What is the difference between the Amperage Calculator and the Voltage drop calculator?

This one returns Current; the Voltage drop calculator returns Voltage drop (V) and Voltage drop (%). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Power dissipation calculator is the closest one after this: Compute the power dissipated by a resistor from current and resistance (P = I²R).

What else is worth having open alongside it?

Battery life calculator and Heat pump savings calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from, and how current are they?

The arithmetic is exact for the rating and the tariff you enter. Nameplate wattage is a maximum, not an average, and solar output depends on latitude, orientation and shading that no formula can guess.

Further reading

All guides →
How-toHow Many Amps Does an Appliance Draw?Divide the appliance wattage by the supply voltage to get the current in amps — the number that decides breaker size, wire, and what can share a circuit.How-toWhat Wire Gauge Do I Need?Pick wire size from the load current, run length, and allowed voltage drop — the amps decide the minimum cross-section, distance forces you thicker.ExplainerHow Many Cables Fit in a Conduit? It Is a Code Question, Not a Geometry QuestionThe 40 % limit for three or more conductors is not about whether they physically fit. It is about heat and about pulling them in without stripping the insulation — and the moment you use that space, the code takes current away from every conductor in the pipe.How-toHow Much Does a Space Heater Cost to Run?Multiply the heater's kilowatts by hours used and your price per kWh — a 1.5 kW heater for 5 hours a day adds up fast at typical tariffs.ExplainerThe Voltage Divider: The Formula Is Trivial, the Assumption Behind It Is NotVout = Vin·R2/(R1+R2) is only true when nothing is connected to the output. Draw current and the voltage collapses, by an amount that follows one exact law. Here is that law, the ten-times rule checked against it, and why a lower-resistance divider costs you power forever.ExplainerWhat Is Voltage Drop? Why Long Wires Lose VoltageVoltage drop is the voltage lost along a wire due to its resistance. Learn how length, gauge, and current affect it, and why it matters for your circuits.