To convert kilocoulombs to amp-hours, multiply by 0.2777777778. That factor is the whole relationship: both units measure the total quantity of electricity, including battery capacity, so the conversion is a proportion with no offset and no substance-specific constant.
Amp-hours rate car, leisure and solar batteries. A 100 Ah battery can in principle deliver one amp for a hundred hours. One kilo coulomb is a thousand of a coulomb (1e3 coulombs).
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. Below the calculator there is a step table for the values people look up most, and a second table putting real the total quantity of electricity, including battery capacity figures into amp-hours so the number you get has something to be compared against.
The formula
kilocoulombs- The amount you are converting, in kilocoulombs
0.277777777778- The exact number of amp-hours in one kilocoulomb
amp-hours- The converted result
How it works, step by step
- Enter the value in kilocoulombs.
- It is multiplied by 0.277777777778, the exact factor between the two units.
- The answer is shown in amp-hours, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
AA alkaline cell: 9 kC in amp-hours
Take aa alkaline cell, roughly 9 kC. The conversion is a single multiplication — 9 × 0.277778 — giving 2.5 Ah. Because the relationship is proportional, doubling the input doubles the answer to 5 Ah.
Phone battery, 4000 mAh: 14.4 kC in amp-hours
Phone battery, 4000 mAh comes to about 14.4 kC. Multiplying by the factor: 14.4 × 0.277778 = 4 Ah. Dividing the answer back by 0.277778 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 amp-hours are in one kilocoulomb?
Exactly 0.277777777778. 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 kilocoulombs to amp-hours?
amp-hours = kilocoulombs × 0.277777777778. Reversed, kilocoulombs = amp-hours ÷ 0.277777777778, which is the same as multiplying by 3.6.
Which is the bigger unit, the kilocoulomb or the amp-hour?
The amp-hour. One kilocoulomb is only 0.277778 of a amp-hour, so it takes 3.6 kilocoulombs to make one amp-hour.
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 kilocoulomb?
One kilo coulomb is a thousand of a coulomb (1e3 coulombs).
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.
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.
Kilocoulombs to amp-hours reference tables
| Kilocoulombs | Amp-Hours |
|---|---|
| 0.5 kC | 0.138889 Ah |
| 1 kC | 0.277778 Ah |
| 2 kC | 0.555556 Ah |
| 3 kC | 0.833333 Ah |
| 5 kC | 1.38889 Ah |
| 10 kC | 2.77778 Ah |
| 20 kC | 5.55556 Ah |
| 25 kC | 6.94444 Ah |
| 50 kC | 13.8889 Ah |
| 75 kC | 20.8333 Ah |
| 100 kC | 27.7778 Ah |
| 250 kC | 69.4444 Ah |
| 500 kC | 138.889 Ah |
| 1000 kC | 277.778 Ah |
| 5000 kC | 1388.89 Ah |
Exact factor: 1 kilocoulomb = 0.277777777778 amp-hours.
| Quantity | kC | Ah |
|---|---|---|
| AA alkaline cell | 9 kC | 2.5 Ah |
| Phone battery, 4000 mAh | 14.4 kC | 4 Ah |
| Laptop battery, 60 Wh at 11.1 V | 19.46 kC | 5.405 Ah |
| Car battery, 60 Ah | 216 kC | 60 Ah |
| Camera flash capacitor | 5e-05 kC | 1.389e-05 Ah |
| Lightning strike | 0.015 kC | 0.004167 Ah |
Published reference values, converted with the same factor this page uses.