How to convert coulombs to ampere-hours
Ah = C × 0.0002777777778Because one ampere-hour equals 3,600 coulombs, you can also divide: Ah = C ÷ 3,600.
A coulomb is smaller than an ampere-hour: it takes 3,600 coulombs to make one ampere-hour.
Worked examples
- 1 coulomb1 C × 0.0002777777778 = 0.0002777777778 Ah
- 5 coulombs5 C × 0.0002777777778 = 0.001388888889 Ah
- 10 coulombs10 C × 0.0002777777778 = 0.002777777778 Ah
- 20 coulombs20 C × 0.0002777777778 = 0.005555555556 Ah
- 100 coulombs100 C × 0.0002777777778 = 0.02777777778 Ah
Coulombs to ampere-hours conversion table
Values are calculated by the conversion engine and rounded to 8 significant figures.
| Coulombs (C) | Ampere-hours (Ah) |
|---|---|
| 0.1 C | 0.000027777778 Ah |
| 0.25 C | 0.000069444444 Ah |
| 0.5 C | 0.00013888889 Ah |
| 1 C | 0.00027777778 Ah |
| 2 C | 0.00055555556 Ah |
| 3 C | 0.00083333333 Ah |
| 4 C | 0.0011111111 Ah |
| 5 C | 0.0013888889 Ah |
| 6 C | 0.0016666667 Ah |
| 7 C | 0.0019444444 Ah |
| 8 C | 0.0022222222 Ah |
| 9 C | 0.0025 Ah |
| 10 C | 0.0027777778 Ah |
| Coulombs (C) | Ampere-hours (Ah) |
|---|---|
| 12 C | 0.0033333333 Ah |
| 15 C | 0.0041666667 Ah |
| 20 C | 0.0055555556 Ah |
| 25 C | 0.0069444444 Ah |
| 30 C | 0.0083333333 Ah |
| 40 C | 0.011111111 Ah |
| 50 C | 0.013888889 Ah |
| 75 C | 0.020833333 Ah |
| 100 C | 0.027777778 Ah |
| 250 C | 0.069444444 Ah |
| 500 C | 0.13888889 Ah |
| 1,000 C | 0.27777778 Ah |
About the units
Coulomb (C)
The SI unit of charge: one ampere for one second.
Ampere-hour (Ah)
3,600 coulombs. Car and deep-cycle batteries are rated in Ah.
Frequently asked questions
How many ampere-hours are in one coulomb?
There are 0.0002777777778 ampere-hours in one coulomb, and this value is exact by definition.
How do I convert coulombs to ampere-hours?
Multiply the number of coulombs by 0.0002777777778. For example, 10 C × 0.0002777777778 = 0.002777777778 Ah.
How many coulombs are in one ampere-hour?
One ampere-hour equals 3,600 coulombs. That is the reverse factor, 1 ÷ 0.0002777777778.
What is 10 coulombs in ampere-hours?
10 C = 0.002777777778 Ah.
Is this C to Ah converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.