Coulomb to Ampere-hour Converter

Enter the value that you want to convert coulomb (C) to ampere-hour (Ah) or ampere-hour to coulomb.Also written as C to AH conversion.

1 coulomb = 0.0002778 ampere-hour

Formula: ampere-hour = coulomb value × 0.0002778

C to AH — coulomb to ampere-hour

Value

Result

0.00278Ah

10 coulomb = 0.00278 ampere-hour

Popular Charge Converters:

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Coulomb vs Ampere-hour

The Coulomb in Electrical Systems

Coulomb (C) is a unit of charge measurement. 1 coulomb is equal to 0.0002778 ampere-hour.

The Ampere-hour in Electrical Systems

Ampere-hour (Ah) is a unit of charge measurement. 1 ampere-hour is equal to 3600.0000000 coulomb.

Electric Charge in Practice

Charge conversions are essential in battery technology, electrochemistry, and particle physics. Battery capacity (ampere-hours and milliampere-hours) must convert to coulombs for electrochemical calculations. The faraday constant connects moles of electrons to coulombs in electrolysis. Capacitor specifications and static discharge calculations also require precise charge unit conversion.

coulomb to ampere-hour metric conversion table

0.01 C	=	0.00000 Ah
0.1 C	=	0.00003 Ah
1 C	=	0.00028 Ah
2 C	=	0.00056 Ah
3 C	=	0.00083 Ah
4 C	=	0.00111 Ah
5 C	=	0.00139 Ah
6 C	=	0.00167 Ah
7 C	=	0.00194 Ah
8 C	=	0.00222 Ah
9 C	=	0.00250 Ah
10 C	=	0.00278 Ah
11 C	=	0.00306 Ah
12 C	=	0.00333 Ah
13 C	=	0.00361 Ah
14 C	=	0.00389 Ah
15 C	=	0.00417 Ah
16 C	=	0.00444 Ah
17 C	=	0.00472 Ah
18 C	=	0.00500 Ah

19 C	=	0.00528 Ah
20 C	=	0.00556 Ah
30 C	=	0.00833 Ah
40 C	=	0.01111 Ah
50 C	=	0.01389 Ah
60 C	=	0.01667 Ah
70 C	=	0.01944 Ah
80 C	=	0.02222 Ah
90 C	=	0.02500 Ah
100 C	=	0.02778 Ah
200 C	=	0.05556 Ah
300 C	=	0.08333 Ah
400 C	=	0.11111 Ah
500 C	=	0.13889 Ah
600 C	=	0.16667 Ah
700 C	=	0.19444 Ah
800 C	=	0.22222 Ah
900 C	=	0.25000 Ah
1000 C	=	0.27778 Ah

How to Convert C to AH (Coulomb to Ampere-hour)?

We can convert coulomb to ampere-hour by using an example.

Example:

Convert 20 Coulomb to Ampere-hour?

We know 1 Coulomb = 0.0002778 ampere-hour; 1 Ampere-hour = 3600.0000000 coulomb.

20 coulomb = ___Ah

20 × 0.0002778 = 0.00556 Ah (we know 1 coulomb = 0.0002778 ampere-hour)

Answer:

20 coulomb = 0.00556 ampere-hour

Coulombs to Amp-Hours: Bridging Physics and Battery Ratings

The coulomb (C) is the SI unit of electric charge — one ampere flowing for one second. Amp-hours (Ah) are the practical unit used to rate batteries, from car batteries to grid storage systems. Since 1 Ah = 1 amp × 1 hour = 1 amp × 3,600 seconds = 3,600 coulombs, you divide coulombs by 3,600 to get Ah.

Start with the electric charge in coulombs (C).
Divide by 3,600 (seconds in one hour).
The result is the charge in amp-hours (Ah).
Verify: 3,600 C ÷ 3,600 = 1 Ah (1 amp flowing for 1 hour).

💡 Tip: A car battery holds about 180,000 C (50 Ah). An EV battery pack at 75 kWh / 400V holds about 187.5 Ah = 675,000 C. These numbers help contextualize what coulombs mean in practical terms.

Coulombs to Ah: Battery Charge Reference

Electric charge values converted from coulombs to amp-hours for battery applications:

Coulomb	Ampere-hour	Note
360 C	0.1 Ah	Small coin cell (CR2032)
3,600 C	1 Ah	AA rechargeable battery
18,000 C	5 Ah	Power tool battery cell
36,000 C	10 Ah	E-bike battery cell
180,000 C	50 Ah	Car starter battery
360,000 C	100 Ah	Deep-cycle RV battery
720,000 C	200 Ah	Large solar storage
1,800,000 C	500 Ah	Industrial UPS bank

Solved: Coulombs to Amp-Hours

Question 1: A capacitor bank stores 7,200 coulombs. What is that in Ah?

Solution:

Ah = C ÷ 3,600

= 7,200 ÷ 3,600

= 2 Ah

Answer: 7,200 C = 2 Ah — equivalent to two AA rechargeable batteries.

Question 2: An electroplating process uses 54,000 coulombs. Convert to Ah for billing.

Solution:

Ah = C ÷ 3,600

= 54,000 ÷ 3,600

= 15 Ah

Answer: 54,000 C = 15 Ah — the electricity consumed during the plating process.

Question 3: A Tesla Model 3 battery holds approximately 280,800 C. Express in Ah.

Solution:

Ah = C ÷ 3,600

= 280,800 ÷ 3,600

= 78 Ah

Answer: 280,800 C = 78 Ah — at ~350V nominal, that gives about 27.3 kWh usable.

Practice: Coulombs to Ah

Try solving these on your own to test your understanding:

Convert 14,400 C to Ah. (Answer: 4 Ah)
A battery delivers 90,000 C before depletion. How many Ah? (Answer: 25 Ah)
Convert 1,800 C to Ah. (Answer: 0.5 Ah)
An experiment uses 432,000 C. Express in Ah. (Answer: 120 Ah)
Convert 5,400 C to Ah. (Answer: 1.5 Ah)

Faraday's Laws and Electrochemistry

In electrochemistry, Faraday's constant (96,485 C/mol) tells you how many coulombs are needed to deposit one mole of a monovalent element. To plate 1 mole of copper (divalent), you need 2 × 96,485 = 192,970 C ≈ 53.6 Ah. Converting between coulombs and Ah helps electroplating shops estimate process time: at 10 A, depositing one mole of copper takes 53.6 Ah ÷ 10 A = 5.36 hours.

Why Batteries Use Ah Instead of Coulombs

Batteries are rated in Ah because it directly tells you how long they last: a 100 Ah battery delivers 1 A for 100 hours, or 10 A for 10 hours (ideally). Coulombs (amp-seconds) would give unwieldy numbers — that same battery is 360,000 C. The Ah unit was adopted in the 19th century when telegraphy demanded multi-hour operation, and the convention stuck because it matches how people think about battery life.

Key Takeaways

Divide coulombs by 3,600 to get amp-hours.
1 Ah = 3,600 C = 1 ampere flowing for exactly 1 hour.
Car batteries: ~50 Ah; EV batteries: ~75-100 Ah.
Faraday's constant (96,485 C) is important for electroplating calculations.
Ah is preferred over coulombs because it relates directly to battery runtime.

Coulomb to Ampere-hour Conversion Formula

ampere-hour = coulomb × 0.0002778

1 coulomb = 0.0002778 ampere-hour

1 ampere-hour = 3600.0000000 coulomb

Reverse: coulomb = ampere-hour × 3600.0000000

Frequently Asked Questions

How many ampere-hour are in 1 coulomb?

There are 0.0002778 ampere-hour in 1 coulomb. To convert coulomb to ampere-hour, multiply the value by 0.0002778.

How do I convert coulomb to ampere-hour?

Multiply your coulomb value by 0.0002778 to get the equivalent in ampere-hour. For example, 5 coulomb = 5 × 0.0002778 = 0.00139 ampere-hour.

How do I convert ampere-hour to coulomb?

Multiply your ampere-hour value by 3600.0000000 to get the equivalent in coulomb. Alternatively, divide by 0.0002778.

What is 10 coulomb in ampere-hour?

10 coulomb is equal to 0.00278 ampere-hour.

What is 100 coulomb in ampere-hour?

100 coulomb is equal to 0.02778 ampere-hour.