The calculation, without hidden assumptions
Joules and watt-hours both measure energy, but they are scaled around different conventions. One watt-hour is exactly 3,600 joules because one watt is one joule per second and one hour contains 3,600 seconds. MAXScanner keeps both conversion directions together, shows the exact factor, and returns nearby energy units so the result can be reused in battery, electronics and power calculations without another conversion step.
How to use this calculator
Choose J → Wh or Wh → J.
Enter the known energy value; no power or time assumption is required because both quantities are energy units.
Review joules, kilojoules, megajoules, watt-hours and kilowatt-hours plus the reverse check.
Where people use it
- •Battery and capacitor energy comparisons
- •Electronics energy calculations
- •Converting SI energy into electrical billing-style units
Example: 7,200 J
7,200 J ÷ 3,600 = 2 Wh. The same energy is 7.2 kJ or 0.0072 MJ.
What the result does not assume
- •This is an energy-unit conversion, not joules-to-watts. Converting energy to power requires a time interval.
- •The arithmetic does not account for conversion efficiency or losses in a real battery, inverter, charger or load.
Frequently asked questions
How many joules are in one watt-hour?+
Exactly 3,600 joules.
Can joules be converted to watts directly?+
Not without time. Watts are power, while joules and watt-hours are energy.
Why include both conversion directions?+
They use the same exact factor, so a single bidirectional canonical page is clearer than duplicate reciprocal pages.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
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