This page converts amp-hours into coulombs using the factor 3600, and shows the reverse figure alongside it. Both units measure the total quantity of electricity, including battery capacity, which is why one number does the whole job.
Amp-hours rate car, leisure and solar batteries. A 100 Ah battery can in principle deliver one amp for a hundred hours. The coulomb is the SI unit of electric charge: one ampere flowing for one second.
Milliamp-hours are charge, not energy. Two batteries both rated 3,000 mAh store different amounts of energy if their voltages differ, which is why power banks advertise mAh at cell voltage and deliver less at USB voltage. Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into coulombs, which is usually more useful than the bare number.
The formula
amp-hours- The amount you are converting, in amp-hours
3600- The exact number of coulombs in one amp-hour
coulombs- The converted result
How it works, step by step
- Enter the value in amp-hours.
- It is multiplied by 3600, the exact factor between the two units.
- The answer is shown in coulombs, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
Phone battery, 4000 mAh: 4 Ah in coulombs
At 4 Ah (phone battery, 4000 mah), the same quantity in coulombs is 4 × 3600 = 14,400 C. One amp-hour is 3600 coulombs, so the numbers grow as expected.
Laptop battery, 60 Wh at 11.1 V: 5.41 Ah in coulombs
Laptop battery, 60 Wh at 11.1 V comes to about 5.41 Ah. Multiplying by the factor: 5.41 × 3600 = 19,476 C. Dividing the answer back by 3600 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many coulombs are in one amp-hour?
Exactly 3600. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert amp-hours to coulombs?
coulombs = amp-hours × 3600. Reversed, amp-hours = coulombs ÷ 3600, which is the same as multiplying by 0.000277777777778.
Which is the bigger unit, the amp-hour or the coulomb?
The amp-hour. One amp-hour equals 3600 coulombs.
What does this quantity actually measure?
Both units measure the total quantity of electricity, including battery capacity. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a amp-hour?
Amp-hours rate car, leisure and solar batteries. A 100 Ah battery can in principle deliver one amp for a hundred hours.
What is a coulomb?
The coulomb is the SI unit of electric charge: one ampere flowing for one second.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Amp-Hours to coulombs reference tables
| Amp-Hours | Coulombs |
|---|---|
| 0.5 Ah | 1800 C |
| 1 Ah | 3600 C |
| 2 Ah | 7200 C |
| 3 Ah | 10,800 C |
| 5 Ah | 18,000 C |
| 10 Ah | 36,000 C |
| 20 Ah | 72,000 C |
| 25 Ah | 90,000 C |
| 50 Ah | 180,000 C |
| 75 Ah | 270,000 C |
| 100 Ah | 360,000 C |
| 250 Ah | 900,000 C |
| 500 Ah | 1.8e+06 C |
| 1000 Ah | 3.6e+06 C |
| 5000 Ah | 1.8e+07 C |
Exact factor: 1 amp-hour = 3600 coulombs.
| Quantity | Ah | C |
|---|---|---|
| AA alkaline cell | 2.5 Ah | 9000 C |
| Phone battery, 4000 mAh | 4 Ah | 1.44e+04 C |
| Laptop battery, 60 Wh at 11.1 V | 5.405 Ah | 1.946e+04 C |
| Car battery, 60 Ah | 60 Ah | 2.16e+05 C |
| Camera flash capacitor | 1.389e-05 Ah | 0.05 C |
| Lightning strike | 0.004167 Ah | 15 C |
Published reference values, converted with the same factor this page uses.