Wh to Joules Converter — Instant Watt Hour to Joule Calculator

Convert Wh to J as you type.

Energy Unit Converter - Instant & Accurate

1 Wh = 3600 J

Reference for one unit; displayed values may be rounded.

Enter Watt Hours

Watt Hours

Use a dot or comma for decimals, without thousands separators.

Result in Joules

Joules

Decimal places

Display rounding does not improve the accuracy of your original measurement. Very large or very small results use scientific notation.

Method and source

Wh to J Conversion Formula

To convert watt hours to joules, multiply the Wh value by 3600. One watt hour is the energy of one watt running for 3600 seconds, and since one watt-second equals one joule, the factor is exactly 3600 — a clean definition-based conversion.

1 Wh = 3600 J

Watt Hours and Joules Explained

Watt Hours (Wh)

The watt hour (Wh) is the energy delivered by one watt of power over one hour, equal to exactly 3600 joules. It is the honest unit for battery capacity because it accounts for voltage, unlike milliamp-hours: a 15 Wh phone battery and a 15 Wh laptop cell carry identical energy despite different mAh ratings. Scales run from 0.7 Wh coin cells through 500 Wh e-bike packs to home solar batteries in the thousands of Wh.

Where it is used: Standard on battery labels, power bank specs, CASA airline lithium regulations (100 Wh and 160 Wh limits), and energy-density datasheets.

Origin: Companion of the kilowatt hour, devised by early electric utilities in the 1880s to bill energy as power multiplied by time; battery makers kept the smaller watt-hour scale.

Joules (J)

The joule (J) is the SI unit of energy — one watt-second, or the work of one newton over one metre. One watt hour is 3600 J, a smartphone battery about 54,000 J, and a litre of petrol roughly 34 million J. Physics equations, chemistry thermochemistry, and engineering simulations all require joules, which is why battery specs in Wh eventually need translating for any SI-based calculation.

Where it is used: Universal across science and engineering; required whenever battery energy enters formulas involving force, heat, velocity, or electrical work in SI form.

Origin: Named for James Prescott Joule, whose experiments in the 1840s unified heat and mechanical energy; the watt-second relationship makes his unit the natural partner of electrical measurement.

Watt Hours to Joules Conversion Table

Select a value to use it in the calculator.

Watt Hours (Wh)	Joules (J)
	360 J
	900 J
	1800 J
	3600 J
	7200 J
	18000 J
	36000 J
	54000 J
	72000 J
	180000 J
	266400 J
	360000 J
	720000 J
	1.800000e+6 J
	3.600000e+6 J

Joules to Watt Hours Conversion Table

Joules (J)	Watt Hours (Wh)
100 J	0.0277777778 Wh
500 J	0.1388888889 Wh
1000 J	0.2777777778 Wh
3600 J	1 Wh
5000 J	1.3888888889 Wh
10000 J	2.7777777778 Wh
36000 J	10 Wh
54000 J	15 Wh
100000 J	27.7777777778 Wh
360000 J	100 Wh
1.000000e+6 J	277.7777777778 Wh
3.600000e+6 J	1000 Wh

Watt Hours to Joules in Everyday Objects

Common real-world examples that make Watt Hours and Joules easy to picture at a glance.

	Watt Hours (Wh)	Joules (J)
A CR2032 coin cell	0.7 Wh	2520 J
A AA alkaline battery	3.9 Wh	14040 J
Charging a smartphone	15 Wh	54000 J
A laptop battery	52.6 Wh	189360 J
A 20,000 mAh power bank	74 Wh	266400 J
An e-bike battery	500 Wh	1.800000e+6 J
The CASA carry-on lithium limit	100 Wh	360000 J

When You Need Watt Hours to Joules Conversions

Power Bank Flight Compliance

CASA lithium rules cap carry-on batteries at 100 Wh. Converting that ceiling to 360,000 J and a 74 Wh bank to 266,400 J shows exactly how much margin remains before airline approval kicks in at the Qantas check-in counter.

IoT Device Power Budgets

Embedded engineers size coin cells in joules to match firmware energy-per-transmission figures — think soil sensors on remote Outback stations. A CR2032's 0.7 Wh becomes 2520 J; a radio burst costing 5 J leaves room for about 500 transmissions before the cell fades.

Drone Flight-Time Engineering

Drone builders mix Wh pack labels with SI motor power draws in watts. A 52.6 Wh pack (189,360 J) against a 260 W hover load predicts roughly 12 minutes of flight — worth knowing before a shoot along the Great Ocean Road.

Comparing Battery Chemistries

Datasheets quote energy density in Wh/kg while research papers use J/kg. An alkaline AA at about 3.9 Wh per 23 g cell translates to 14,040 J — directly stackable against Li-ion chemistry tables in SI units.

Related Energy Conversions

Joules to Kilojoules & Calories Converter

Joules → Calories

Calories to Joules Converter — Convert cal to J & kJ Instantly

Calories → Joules

kWh to MJ Converter — Kilowatt Hours to Megajoules for Aussie Bills

Kilowatt Hours → Megajoules

MJ to kWh Converter — Convert Megajoules to Kilowatt Hours for Gas Bills

Megajoules → Kilowatt Hours

BTU to Joules Converter — Get Results in J, kJ & MJ

BTU → Joules

Joules to BTU Calculator — Free Online Energy Conversion

Joules → BTU

Convert Electron Volts to Joules Online — Free eV to J Energy Converter

Electron Volts → Joules

Calories to Kilojoules Converter — kcal to kJ for Australian Food Labels

Kilocalories → Kilojoules

BTU to kWh Converter for Australian Air Conditioners & Heaters

BTU → Kilowatt Hours

How to Use

1

Enter Watt Hours

Type the Wh value from a battery label or datasheet — common entries include 0.7 for a CR2032 coin cell, 15 for a smartphone, and 74 for a 20,000 mAh power bank in the camp kit
2

View Joules

The SI equivalent appears instantly: a 52.6 Wh laptop battery converts to 189,360 J, ready for physics-style energy calculations
3

Copy or Swap

Copy the result or click Swap to convert joules back to watt hours for reverse checks
4

Estimate Runtime

Use the joule figure in power budgets: a device drawing 0.5 W consumes 1800 J per hour, so a 54,000 J (15 Wh) charge runs it for about 30 hours before efficiency losses — handy maths for planning an off-grid weekend

Why Use Be Converter?

Instant Conversion

Get precise Wh to joule results in real time as you type — ideal for sizing camping power stations and estimating 12V fridge runtime

Exact 3600 Factor

Because 1 Wh = 3600 J by definition, values like 10 Wh always convert to exactly 36,000 J with no rounding whatsoever

Conversion Table

Quick reference across battery sizes — 0.7 Wh coin cell (2520 J), 15 Wh phone charge (54,000 J), 74 Wh power bank (266,400 J), and a 1000 Wh camping power station (3,600,000 J)

Bidirectional

Easily swap between watt hours and joules with one click when checking spec sheets against SI calculations

Free & No Signup

No registration required. Unlimited conversions. Completely free, no strings attached

Privacy First

All calculations happen right in your browser. No data ever leaves your device

Frequently Asked Questions

How many joules are in 1 watt hour?

1 watt hour equals exactly 3600 joules — one watt sustained for 3600 seconds, with each watt-second being one joule. In reverse, 1 joule is 1/3600 Wh, or about 0.000278 Wh.

How do I convert 100 Wh to joules?

Multiply by 3600: 100 × 3600 = 360,000 J (360 kJ). 100 Wh is also the carry-on lithium limit enforced under CASA rules by Qantas, Virgin Australia and Jetstar, so that ceiling equals a hard 360,000 J of stored energy in your cabin bag.

Why do batteries use Wh instead of joules?

Watt hours pair naturally with the watts that devices draw, making runtime mental maths easy — a 10 Wh cell runs a 1 W gadget for ten hours. Physics equations, though, need SI joules, and 1 Wh = 3600 J bridges the two views exactly.

How do I convert mAh to watt hours first?

Multiply milliamp-hours by voltage and divide by 1000: a 3000 mAh phone battery at 3.7 V is 11.1 Wh. Then convert to joules: 11.1 × 3600 = 39,960 J. mAh alone cannot get you to energy without the voltage.

Is a watt hour bigger than a joule?

Much bigger — 1 Wh = 3600 J, a factor of 3600 from the seconds in an hour. So converting Wh to J should always make the number roughly 3600 times bigger; anything else means a slipped factor or unit.

How many joules is a 20,000 mAh power bank?

A 20,000 mAh power bank at 3.7 V stores 74 Wh, which is 74 × 3600 = 266,400 J. After voltage conversion losses it delivers roughly 50 Wh usable — about 180,000 J to your devices, plenty for a weekend away.

What is 1 kWh in watt hours and joules?

1 kWh = 1000 Wh = 3,600,000 J. The kilowatt hour is simply a thousand watt hours, so the same 3600 factor cascades: 1000 × 3600 = 3.6 million joules — the unit behind every Australian electricity bill, and worth watching when your rooftop solar is cranking on a summer's day.

Do drone and RC hobby packs use Wh?

Yes, and CASA caps them in Wh too. A typical 4S 5000 mAh drone pack at 14.8 V holds 74 Wh (266,400 J); spare packs above 100 Wh (360,000 J) need airline approval, and 160 Wh is the usual hard ceiling on domestic flights.

About Watt Hours to Joules Converter

Our free online watt hours to joules converter gives instant, accurate energy conversions for batteries, power stations, and electronics design. The watt hour is the battery industry's favourite unit — capacity labels, airline lithium limits, and energy-density specs all quote Wh, because it compares fairly across voltages. The joule is the SI unit every physics formula and engineering simulation expects. The conversion is exact by definition: 1 Wh = 3600 J. Whether you're working out stored energy for an off-grid camping setup, checking a power bank before a Qantas flight, sizing a home solar battery, or turning mAh-and-voltage specs into SI energy, this tool handles it in one step.

Expert Tips for Wh to J Conversion

The factor 3600 is exact (3600 seconds per hour, one joule per watt-second). Scale it freely: 1 Wh = 3600 J, 1 kWh = 3,600,000 J, 1 mWh = 3.6 J.

Battery benchmarks in joules: CR2032 coin cell 0.7 Wh = 2520 J, AA alkaline about 3.9 Wh = 14,040 J, smartphone 15 Wh = 54,000 J, MacBook-class laptop 52.6 Wh = 189,360 J.

Travelling rule: the 100 Wh lithium limit equals 360,000 J and the 160 Wh ceiling is 576,000 J. Converting to joules makes the safety margin tangible when you're packing spare packs for a domestic flight.

Runtime maths in SI: a sensor drawing 10 mW uses 36 J per hour, so a 2520 J coin cell (0.7 Wh) theoretically lasts 70 hours — derate 20-30% for real quiescent draw, and more through a 40°C Outback summer day.

Energy-density comparisons: petrol at about 12,700 Wh/kg (45.7 million J/kg) versus a Li-ion pack near 250 Wh/kg (900,000 J/kg) — the 50-fold gap is why EV range across the Nullarbor takes planning.

Professional-grade conversion tools for length, weight, area, volume, temperature, pressure, speed, time, and energy measurements