Convert Coulomb to Ampere-hour
Use this free converter to change coulombs (C) into ampere-hours (Ah). Coulomb and ampere-hour both measure electric charge. As a quick reference, 1 C equals 0.00027777778 Ah, and 1 Ah equals 3600 C.
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Ampere-hour (Ah)
0.00027777778
1 C = 0.00027777778 Ah
Electric Charge conversion table
| Coulomb | Ampere-hour |
|---|---|
| 0.01 | 0.0000027777778 |
| 0.1 | 0.000027777778 |
| 0.5 | 0.00013888889 |
| 1 | 0.00027777778 |
| 2 | 0.00055555556 |
| 3 | 0.00083333333 |
| 5 | 0.0013888889 |
| 10 | 0.0027777778 |
| 20 | 0.0055555556 |
| 25 | 0.0069444444 |
| 50 | 0.013888889 |
| 100 | 0.027777778 |
| 1,000 | 0.27777778 |
How to convert Coulomb to Ampere-hour
Multiply the coulomb value by 0.00027777778 to get ampere-hours.
- Enter the number of coulombs you want to convert.
- The converter instantly shows the equivalent value in ampere-hours.
- Worked example: 15 C × 0.00027777778 = 0.0041666667 Ah.
- Use the swap button to reverse the conversion (ampere-hour to coulomb).
About these units
Coulomb (C)
- Definition
- The coulomb (C) is the SI unit of electric charge, defined as the charge transported by one ampere of current in one second.
- History
- Named after French physicist Charles-Augustin de Coulomb, it was formalised with the SI system and redefined in 2019 in terms of the elementary charge.
- Current use
- Coulombs are used in electrochemistry, capacitor ratings, and electrostatics calculations.
Ampere-hour (Ah)
- Definition
- An ampere-hour (Ah) is a unit of electric charge equal to 3,600 coulombs — the charge transferred by one ampere flowing for one hour.
- History
- It came into widespread use with the commercialisation of lead-acid batteries in the late 19th century.
- Current use
- Ampere-hours rate battery capacity in electric vehicles, uninterruptible power supplies, and solar storage systems.
Frequently asked questions
How many ampere-hours are in a coulomb?
There are 0.00027777778 Ah in 1 C. To convert, multiply the number of coulombs by 0.00027777778.
How do I convert coulombs to ampere-hours?
Multiply the coulomb value by 0.00027777778 to get ampere-hours. For example, 10 C = 0.0027777778 Ah.
Is this coulomb-to-ampere-hour converter free?
Yes. This converter is completely free, runs entirely in your browser, and requires no sign-up. Your inputs never leave your device.
Convert Coulomb to other electric charge units
| Unit | 1 Coulomb equals |
|---|---|
| Millicoulomb (mC) | 1000 mC |
| Microcoulomb (µC) | 1000000 µC |
| Nanocoulomb (nC) | 1000000000 nC |
| Ampere-hour (Ah) | 0.00027777778 Ah |
| Milliampere-hour (mAh) | 0.27777778 mAh |