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Coulomb to Milliampere-hour Converter

Enter the value that you want to convert coulomb (C) to milliampere-hour (mAh) or milliampere-hour to coulomb.Also written as C to MAH conversion.

1 coulomb = 0.2777778 milliampere-hour

Formula: milliampere-hour = coulomb value × 0.2777778

C to MAH — coulomb to milliampere-hour

C
2.77778mAh

10 coulomb = 2.77778 milliampere-hour

Popular Charge Converters:

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How Coulomb Relates to Milliampere-hour

The Coulomb in Electrical Systems

Coulomb (C) is a unit of charge measurement. 1 coulomb is equal to 0.2777778 milliampere-hour.

The Milliampere-hour in Electrical Systems

Milliampere-hour (mAh) is a unit of charge measurement. 1 milliampere-hour is equal to 3.6000000 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 milliampere-hour metric conversion table

0.01 C=0.00278 mAh
0.1 C=0.02778 mAh
1 C=0.27778 mAh
2 C=0.55556 mAh
3 C=0.83333 mAh
4 C=1.11111 mAh
5 C=1.38889 mAh
6 C=1.66667 mAh
7 C=1.94444 mAh
8 C=2.22222 mAh
9 C=2.50000 mAh
10 C=2.77778 mAh
11 C=3.05556 mAh
12 C=3.33333 mAh
13 C=3.61111 mAh
14 C=3.88889 mAh
15 C=4.16667 mAh
16 C=4.44444 mAh
17 C=4.72222 mAh
18 C=5.00000 mAh
19 C=5.27778 mAh
20 C=5.55556 mAh
30 C=8.33333 mAh
40 C=11.11111 mAh
50 C=13.88889 mAh
60 C=16.66667 mAh
70 C=19.44444 mAh
80 C=22.22222 mAh
90 C=25.00000 mAh
100 C=27.77778 mAh
200 C=55.55556 mAh
300 C=83.33333 mAh
400 C=111.11111 mAh
500 C=138.88889 mAh
600 C=166.66667 mAh
700 C=194.44444 mAh
800 C=222.22222 mAh
900 C=250.00000 mAh
1000 C=277.77778 mAh

How to Convert C to MAH (Coulomb to Milliampere-hour)?

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

Example:

Convert 20 Coulomb to Milliampere-hour?

We know 1 Coulomb = 0.2777778 milliampere-hour; 1 Milliampere-hour = 3.6000000 coulomb.

20 coulomb = ___mAh

20 × 0.2777778 = 5.55556 mAh (we know 1 coulomb = 0.2777778 milliampere-hour)

Answer:

20 coulomb = 5.55556 milliampere-hour

Coulombs to Milliamp-Hours: Phone and Device Battery Math

Milliamp-hours (mAh) is the unit you see on every phone battery, power bank, and wireless earbud. It tells you how many milliamps a battery can deliver for one hour. Since 1 mAh = 0.001 A × 3,600 s = 3.6 C, converting coulombs to mAh means dividing by 3.6. This conversion is useful when calculating how long a device will run from a given charge.

  1. Take the charge in coulombs (C).
  2. Divide by 3.6.
  3. The result is the capacity in milliamp-hours (mAh).
  4. Alternatively: mAh = C × 1,000 ÷ 3,600 = C ÷ 3.6.
💡 Tip: A typical smartphone battery is 5,000 mAh = 18,000 C. That sounds like a lot of charge, but at 500 mA screen-on current draw, it lasts 10 hours. The mAh rating makes this runtime calculation intuitive.

Coulombs to mAh: Device Battery Reference

Common charge values and their mAh equivalents for consumer electronics:

CoulombMilliampere-hour
0.36 C100 mAh
1.08 C300 mAh
3.6 C1,000 mAh
10.8 C3,000 mAh
18 C5,000 mAh
36 C10,000 mAh
72 C20,000 mAh
180 C50,000 mAh

Solved Examples: Coulombs to mAh

Question 1: A LiPo cell stores 14.4 C of charge. What is the capacity in mAh?

Solution:

mAh = C ÷ 3.6

= 14.4 ÷ 3.6

= 4,000 mAh

Answer: 14.4 C = 4,000 mAh — a typical drone battery cell capacity.

Question 2: An experiment delivers 0.72 C to a small LED circuit. Express in mAh.

Solution:

mAh = C ÷ 3.6

= 0.72 ÷ 3.6

= 200 mAh

Answer: 0.72 C = 200 mAh — a small button cell could supply this.

Question 3: A solar panel charges a battery with 54 C over an afternoon. How many mAh?

Solution:

mAh = C ÷ 3.6

= 54 ÷ 3.6

= 15,000 mAh

Answer: 54 C = 15,000 mAh — enough to fully charge three average phones.

Practice: Coulombs to mAh

Try solving these on your own to test your understanding:

  1. Convert 9 C to mAh. (Answer: 2,500 mAh)
  2. A battery holds 25.2 C. What is that in mAh? (Answer: 7,000 mAh)
  3. Convert 1.8 C to mAh. (Answer: 500 mAh)
  4. A capacitor stores 0.036 C. Express in mAh. (Answer: 10 mAh)
  5. Convert 108 C to mAh. (Answer: 30,000 mAh)

Power Bank Real Capacity vs. Advertised mAh

A 20,000 mAh power bank (72 C at 3.7V cell voltage) cannot deliver 20,000 mAh at 5V USB output due to voltage conversion losses. Actual available capacity at 5V is about 20,000 × 3.7 ÷ 5 × 0.9 (efficiency) ≈ 13,320 mAh. This is why a "20,000 mAh" bank charges a 5,000 mAh phone only 2.5 times, not 4 times. The coulomb rating (72 C) stays constant regardless of output voltage.

C-Rating and Discharge Rate

A battery's C-rating tells you its maximum safe discharge rate. A 5,000 mAh (18 C) battery rated at 2C can deliver 10,000 mA (10 A) continuously. For drones, 30C or higher is common: a 5,000 mAh 30C pack can deliver 150 A peak. The coulomb charge stored does not change with C-rating — it only determines how fast you can extract it. Higher C-rating = more powerful but not more capacity.

Key Takeaways

  • Divide coulombs by 3.6 to get mAh.
  • 1 mAh = 3.6 C; a 5,000 mAh phone battery = 18 C.
  • Power bank usable mAh at 5V ≈ rated mAh × 3.7/5 × 0.9.
  • C-rating affects discharge speed, not total stored charge.
  • The coulomb value is voltage-independent; mAh ratings assume nominal cell voltage.

Coulomb to Milliampere-hour Conversion Formula

milliampere-hour = coulomb × 0.2777778

1 coulomb = 0.2777778 milliampere-hour

1 milliampere-hour = 3.6000000 coulomb

Reverse: coulomb = milliampere-hour × 3.6000000

Frequently Asked Questions

How many milliampere-hour are in 1 coulomb?

There are 0.2777778 milliampere-hour in 1 coulomb. To convert coulomb to milliampere-hour, multiply the value by 0.2777778.

How do I convert coulomb to milliampere-hour?

Multiply your coulomb value by 0.2777778 to get the equivalent in milliampere-hour. For example, 5 coulomb = 5 × 0.2777778 = 1.38889 milliampere-hour.

How do I convert milliampere-hour to coulomb?

Multiply your milliampere-hour value by 3.6000000 to get the equivalent in coulomb. Alternatively, divide by 0.2777778.

What is 10 coulomb in milliampere-hour?

10 coulomb is equal to 2.77778 milliampere-hour.

What is 100 coulomb in milliampere-hour?

100 coulomb is equal to 27.77778 milliampere-hour.