mAh to Ah Calculator
Enter milliamp-hours below — the amp-hours update instantly.
How do you convert mAh to Ah?
Divide milliamp-hours by 1,000. A 20,000 mAh power bank equals 20,000 ÷ 1,000 = 20 Ah. A 3,000 mAh 18650 cell is 3 Ah. Because 1 Ah = 1,000 mAh, the conversion is a simple decimal shift — useful when a spec sheet lists a phone battery in mAh but a solar charger in Ah.
mAh to Ah Formula
The prefix "milli" means one-thousandth, so 1,000 milliamp-hours make one amp-hour. Dividing by 1,000 shifts the decimal three places, turning 20,000 mAh into 20 Ah. Note that mAh describes charge only — to compare energy, first convert to watt-hours with the battery voltage.
mAh to Ah Conversion Table
| Milliamp-hours | Amp-hours | Typical example |
|---|---|---|
| 500 mAh | 0.5 Ah | Small remote / toy |
| 1,500 mAh | 1.5 Ah | AA NiMH cell |
| 2,000 mAh | 2 Ah | Older smartphone |
| 3,000 mAh | 3 Ah | 18650 Li-ion cell |
| 10,000 mAh | 10 Ah | Compact power bank |
| 20,000 mAh | 20 Ah | Large power bank |
| 50,000 mAh | 50 Ah | Portable jump starter |
Moving Between Electronics and High-Power Batteries
Milliamp-hours (mAh) are standard in the smartphone and gadget industry because the numbers sound impressively large. Once you move into cordless power tools, e-bikes, and marine batteries, manufacturers switch to Amp-hours (Ah). Converting between them helps you compare scales:
- iPhone 15 Pro Max Battery: ~4,422 mAh.
Converted to Ah: 4,422 ÷ 1,000 = 4.42 Ah. - Standard Cordless Drill Battery (e.g., Makita 18V LXT): 5.0 Ah.
Converted to mAh: 5.0 × 1,000 = 5,000 mAh. A heavy power tool battery holds a roughly similar Ah charge to a flagship smartphone, though at a much higher voltage (18V vs 3.8V), meaning the tool battery holds nearly 5 times more actual energy. - Marine Deep Cycle Battery: 100 Ah.
Converted to mAh: 100 × 1,000 = 100,000 mAh. This highlights why large batteries use Ah; writing 100,000 mAh on a label is cumbersome and confusing.
Frequently Asked Questions
How do I convert mAh to Ah?
Divide the milliamp-hours by 1,000: Ah = mAh ÷ 1,000. For example, 20,000 mAh ÷ 1,000 = 20 Ah — just move the decimal three places left.
How many Ah is 10,000 mAh?
10,000 mAh equals 10 Ah (10,000 ÷ 1,000). That is charge capacity only — energy also depends on voltage.
Is a 20,000 mAh power bank really 20 Ah of usable charge?
The cells hold 20 Ah at their 3.7 V nominal voltage, but the bank outputs 5 V USB. After the voltage step-up and losses, usable charge at 5 V is lower — often ~12,000–14,000 mAh. To compare fairly, convert to energy with our mAh to Wh tool.
What is the difference between mAh and Ah?
They measure the same thing — charge capacity — at different scales: 1 Ah = 1,000 mAh. Small cells are rated in mAh; car and solar batteries are rated in Ah.
Why do phone power banks use mAh instead of Ah?
Marketing is the primary reason. A '10,000 mAh' power bank sounds much more impressive to consumers than a '10 Ah' power bank, even though they represent the exact same capacity. Industry convention keeps mAh for small gadgets and Ah for larger lead-acid or e-bike packs.