Electrical Unit Converter Online Free

A circuit running at 230 volts and drawing 10 amps is using 2300 watts of power — which is also 2.3 kilowatts, 3.084 horsepower, and 7847.93 BTU per hour if it is a heater turning every watt into warmth. One electrical fact, four languages. An electrical unit converter works both halves of that translation: it completes the power triangle P = V x I, finding whichever of power, voltage or current you do not know from the two you do, and it converts the resulting watts into kilowatts, horsepower and BTU per hour. The converter at the top of this page asks for exactly two of the three triangle values, works out the third with the step shown, and prints the power in all four units. Enter 230 volts and 10 amps, as in the live test, and it returns "Power = 2300 W = 2.3 kW = 3.084 hp = 7847.93 BTU per hour", with the full set — voltage 230 V, current 10 A, power 2300 W — confirmed underneath.

The two halves belong together because real questions arrive mixed. A heater is labelled in watts, a breaker in amps, a motor in horsepower or kilowatts, an air conditioner in BTU per hour, and a supply in volts. Deciding whether a circuit can carry a load, whether a generator can run a tool, or whether a replacement motor matches the old one means moving between all of these without dropping a factor of a thousand on the way. This converter keeps the triangle and the unit conversions on one page so the whole chain — volts and amps to watts, watts to the unit the next person uses — happens in one place, with the arithmetic printed.

What the Power Triangle Is

Electrical power in a simple circuit is the product of the push and the flow: power in watts equals voltage in volts times current in amps, P = V x I. Voltage is the electrical pressure, current is the rate of flow of charge, and their product is the rate at which energy is delivered. The relation can be rearranged by ordinary algebra into its three forms: P = V x I when power is unknown, I = P / V when current is unknown, and V = P / I when voltage is unknown. Those three forms are the power triangle, often drawn with P on top and V and I below: cover the unknown, and the arrangement of the other two tells you whether to multiply or divide. It is a sibling of Ohm's law, V = I x R, which ties the same voltage and current to resistance; together they govern every simple circuit calculation, and this tool covers the power half of the family.

The equation is exact for direct current — battery circuits, vehicle electrics, solar panels feeding a resistive load, USB and charger ratings. For alternating current it is exact when the load behaves like a plain resistor, as heaters, kettles, toasters and incandescent lamps do: their current rises and falls in step with the voltage, so the simple product gives the true power. For motors, compressors and most electronic power supplies on AC, the current and voltage fall out of step, and true power is V x I multiplied by a power factor below 1. The tool states this scope on its own page and in the limits below: it computes the triangle exactly as far as the triangle goes, and does not pretend the power factor away.

The four power units are linked by exact factors. The watt is the base unit. A kilowatt is exactly 1000 watts. Horsepower, the older engineering unit, converts at 1 kilowatt = 1.34102209 horsepower, so one horsepower is about 746 watts — a coincidence worth remembering, as the worked examples show. The BTU per hour is the heating and cooling industry's unit: one watt is 3.41214163 BTU per hour, because a BTU is a defined quantity of heat energy and an hour is a defined time. The tool applies these factors at stated rounding: horsepower to three decimal places, BTU per hour to two.

How to Use the Converter

Using the tool takes a few seconds. Follow these steps:

1. Decide which two of the three values you know — voltage, current, or power — and enter them in their boxes. The live test enters voltage 230 and current 10.
2. Leave the third box empty. Filling all three, or only one, produces a clear message rather than a guess: the tool requires exactly two.
3. Press "Calculate and Convert".
4. Read the headline line giving the power in watts, kilowatts, horsepower and BTU per hour, then the full-set line confirming all three triangle values, then the working, which shows the triangle step and each unit conversion.

If a division by zero would be needed — for instance, power and zero current, which cannot yield a voltage — the tool says so plainly instead of printing an infinity.

Worked Examples

Example 1: Volts and amps to power, the live test

Enter voltage 230 and current 10, leaving power empty. The tool returns "Power = 2300 W = 2.3 kW = 3.084 hp = 7847.93 BTU per hour", with the working "Power step: P = V x I = 230 x 10 = 2300 W", then "Kilowatts: 2300 / 1000 = 2.3 kW", "Horsepower: 2.3 x 1.34102209 = 3.084 hp" and "BTU per hour: 2300 x 3.41214163 = 7847.93 BTU/h". A 2300 W resistive load is a large fan heater or a fast kettle, and the conversions are the ones its owner actually meets: 2.3 kW on an electricity tariff, 7847.93 BTU per hour against a room heater's heating rating, and 3.084 hp as a sense of scale — this modest appliance is briefly doing the work of three horses, which is why horsepower survives as an intuition long after it left the nameplate.

Example 2: Finding the current, volts and watts given

Enter voltage 230 and power 2300, leaving current empty. The tool applies I = P / V and returns current 10 amps, with the identical power conversions. This direction is the electrician's everyday question — "the appliance is rated 2300 W, the circuit is 230 V, how many amps will it draw?" — and the answer decides breaker and cable adequacy. A second case at heater scale: voltage 230, power 2000 gives I = 2000 / 230 = 8.695652 A, power conversions 2 kW, 2.682 hp and 6824.28 BTU per hour. The long decimal on the current is honest: 2000 divided by 230 does not terminate, and the tool shows six decimal places rather than rounding the breaker decision to "about 9".

Example 3: Finding the voltage, amps and watts given

Enter current 10 and power 2300, leaving voltage empty. The tool applies V = P / I and returns 230 volts. This direction appears when a load's current and power are measured or stamped but the supply is in question — checking that a generator, an inverter or a long extension run is actually delivering the intended voltage under load. The three directions are one relation viewed three ways, and the tool's insistence on exactly two inputs is what keeps them straight: whichever box you leave empty is the one it solves for.

Example 4: A charger, and the horsepower coincidence

Enter voltage 12 and current 5: the tool returns 60 W, 0.06 kW, 0.080 hp and 204.73 BTU per hour — a car battery charger or a small 12 V appliance, the DC case where the triangle is exact without qualification. Then the memorable benchmark: a load of 746 W. Enter voltage 230 and power 746 and the tool returns 0.746 kW and exactly 1.000 hp at its three-decimal display, drawing 3.243478 A. One horsepower is 745.7 watts by the conversion, so 746 W is the traditional one-horsepower motor size, and generations of "1 hp" pumps and compressors are really 746-watt-class machines. The BTU figure for the same load, 2545.46 BTU per hour, is the size of a small room heater — three industries, one quantity of power.

Where Electrical Conversions Are Used

Circuit sizing is the first use: breakers, fuses and cables are rated in amps, appliances in watts, supplies in volts, and the triangle is the only safe route between an appliance label and a circuit decision — as Example 2 shows, a 2000 W heater on 230 V draws 8.695652 A, a figure that must be compared against the circuit's rating exactly, not guessed. Motor and machinery work is the second: nameplates mix kilowatts and horsepower across countries and decades, and a replacement motor specified in the other unit must match the original's 1.34102209-to-the-kilowatt conversion, not a rough one and a half. Heating and cooling is the third: boilers, heaters and air conditioners are rated in BTU per hour in American catalogues and in kilowatts elsewhere, at 3.41214163 BTU per hour to the watt. Renewable and vehicle electrics — solar arrays, inverters, chargers, 12 V systems — live on the DC side, where the triangle is unconditional. And electricity billing literacy sits behind all of it: the kilowatt here is a rate of power, and the kilowatt-hour on a bill is that rate sustained for an hour, a distinction the common mistakes section takes up, because confusing them mis-sizes everything from generators to battery banks.

How to Read the Output

The headline line is the conversion summary: one power, four units, in the order watts, kilowatts, horsepower, BTU per hour. The line beneath it is the check: "Full set: voltage = 230 V, current = 10 A, power = 2300 W" restates the whole triangle, including the two values you entered, so a mis-typed input shows up immediately as a wrong echo. The working line then prints the triangle step in the direction you used — P = V x I, I = P / V, or V = P / I — followed by the three unit conversions with their factors visible. Horsepower is shown to three decimal places and BTU per hour to two, by the rule printed under the result; volts, amps, watts and kilowatts are shown exactly with trailing zeros trimmed, so 2.3 kW appears as 2.3 and not dressed up with invented precision.

Common Mistakes

The first common mistake is filling all three boxes with values from a motor's nameplate and expecting agreement: the nameplate watts of a motor are usually its mechanical output or its nominal rating, its current is drawn at a power factor below 1, and the simple triangle honestly cannot reconcile all three — the tool's exactly-two rule exists to force the user to choose which two quantities they actually trust. The second mistake is confusing kilowatts with kilowatt-hours: a 2.3 kW heater uses 2.3 kilowatt-hours per hour of running; watts measure the rate, hours measure the duration, and a converter of power units says nothing about energy until a time is supplied. The third is applying P = V x I to an AC motor or an LED driver and reporting the product as true power, ignoring the power factor the tool warns about — for a resistive heater the product is true power; for a motor it is an upper bound. The fourth is the thousand-fold slip between watts and kilowatts in the horsepower conversion: horsepower multiplies kilowatts, not watts, so 2300 must become 2.3 before the 1.34102209 factor applies — the tool's steps print the kilowatts step first precisely so this order is visible. The fifth is treating three-phase power as a bigger version of the same triangle: three-phase systems involve the square root of three and usually a power factor, and are outside this tool's stated scope.

Limits: What This Tool Does and Does Not Do

This tool computes the missing value of the simple power triangle from any two of voltage, current and power, and converts the power between watts, kilowatts, horsepower (at 1 kW = 1.34102209 hp) and BTU per hour (at 1 W = 3.41214163 BTU/h), with steps and stated rounding. It assumes the simple triangle: DC circuits, or AC loads that behave resistively. It does not apply a power factor, so for motors, compressors and electronic loads on AC its triangle result is the apparent product, not the true power — it says so on the page rather than letting the figure pass as exact. It does not handle three-phase power, Ohm's-law resistance calculations (that needs the V = I x R sibling relation), energy in kilowatt-hours, or efficiency losses between electrical input and mechanical output — a "1 hp" motor draws more than 746 electrical watts in practice, because no motor is perfectly efficient. Within its stated scope the arithmetic is exact, and where the physics needs more than the triangle, the tool's silence is deliberate.

Privacy: Your Numbers Stay in Your Browser

Every number you enter into this electrical unit converter stays in your browser. Nothing is uploaded to a server, nothing is stored, and there is no account to create. The calculation runs entirely on your own device. Closing the page removes your inputs, and no one else sees them. This browser-only design is the same principle behind the other free tools on Your Smart Kit: a simple tool that does one job well, keeps your data private, and gives an answer you can check.

Frequently Asked Questions

How many watts is 230 volts at 10 amps?

2300 watts — the live test: P = V x I = 230 x 10. That is 2.3 kW, 3.084 hp, or 7847.93 BTU per hour as heat.

How do I find the amps of an appliance from its watts?

Divide watts by volts: I = P / V. A 2000 W heater on a 230 V supply draws 2000 / 230 = 8.695652 A. Enter the voltage and the power in the tool, leave current empty, and it performs exactly this step.

How many horsepower is a kilowatt?

One kilowatt is 1.34102209 horsepower, and one horsepower is about 746 watts. A 746 W load converts to 1.000 hp at the tool's three-decimal display, as the worked example shows.

What is a BTU per hour in watts?

One watt is 3.41214163 BTU per hour, so divide a BTU-per-hour rating by 3.41214163 to get watts, or multiply watts by it to get BTU per hour. A 2300 W heater is 7847.93 BTU per hour.

Why does the tool ask for exactly two values?

Because the triangle has three values and any two fix the third. One value cannot fix anything, and three values can contradict each other — especially from motor nameplates — so the tool solves for the empty box and refuses the ambiguous cases with a message.

Can I use this for a motor on AC mains?

With care. The tool computes V x I exactly, but a motor's true power also involves its power factor, so treat the result as the apparent product — an upper bound on true power — not as the motor's consumption. For resistive loads and DC, the result is the true power.

Related Tools on Your Smart Kit

If you found the electrical unit converter useful, you may also like the other free converters on Your Smart Kit, including the cc converter, where horsepower figures meet engine sizes, the unit converter for length, volume, temperature and more, and the wavelength to energy converter for physics quantities in the other direction. Each runs in your browser, free, with no sign-up, and each is built on the same principle: a simple tool that does one job well, keeps your data private, and gives an answer you can check. Try the electrical unit converter at the top of this page with the two values stamped on your next appliance, heater or motor, and read the third value — and every unit it is spoken in — straight back.