CPAP Battery Calculator
Estimate how many nights a power station runs your CPAP. Pick your machine, set the humidifier and heated tube, hours per night and nights away. The calculator multiplies watts × hours, divides by 0.95 on 12V DC or 0.85 on AC, then totals the battery Wh you need.
Battery Wh per night = machine watts × hours of sleep ÷ 0.95 (12V DC) or 0.85 (AC) Total battery Wh = Wh per night × nights Nights per charge = station Wh × 0.95 or 0.85 ÷ (machine watts × hours) Results stay in this browser and are not saved. Copy the summary or shareable link to keep them.
Your CPAP setup
Results update automatically after 300ms, or use Recalculate.
DC is the CPAP community standard: a manufacturer 12V cable skips the inverter and typically buys 20–30% more runtime.
Frequently asked questions
How many watts does a CPAP use?
Most CPAP machines draw 30–60W without the heated humidifier, and 60–90W with it on high. Heated tubing adds more. Turning the humidifier off is the single biggest way to extend battery runtime.
Should I turn off the heated humidifier when running on battery?
For camping or outages, humidification roughly doubles power draw, so most users run the machine dry for a few nights. Follow your equipment provider's guidance on what is comfortable and safe for you.
What does the 12V DC cable do for CPAP runtime?
A manufacturer 12V DC car adapter lets the CPAP skip the power station's AC inverter and the machine's own AC-to-DC conversion. Owners routinely report 20–30% longer runtime this way, which is why this calculator defaults to DC.
Can I fly with a power station for my CPAP?
No — power stations (300Wh+) far exceed the FAA's 100Wh lithium battery limit for carry-ons. For flying, use a purpose-built CPAP travel battery under 100Wh instead, and check your airline's medical device policy.