Here's the formula in plain English:
- Convert mAh to watt-hours: (mAh × V) ÷ 1000
- Divide by power draw in watts: watt-hours ÷ W = hours of continuous use
- Adjust for efficiency (optional): multiply by 0.85
Example: A 3000mAh battery at 3.7V has 11.1 watt-hours. At 20W, that's 0.55 hours of continuous use—about 33 minutes. If your customer vapes for 3 seconds every minute, that's roughly 11 hours of casual use.
That's the logic our calculator automates. Instead of doing this for every device, plug in the numbers and get the answer instantly.
