Power Station Runtime Calculator
How long will your power station run your devices? Add everything you want to power, pick your power station (or enter its capacity), and get a runtime instantly, using the same formula as our sizing guides and measured usable energy from independent tests.
Power stations that can run this load
Stations with enough output for 70W that also cover your target, cheapest first. Runtime uses independently measured usable energy where available.
Bluetti Elite 200 V2
1,910Wh measured · 2,600W output
Jackery Explorer 2000 v2
1,710Wh measured · 2,200W output
EcoFlow DELTA 2 Max
1,800Wh measured · 2,400W output
Output is the continuous rating; motors and compressors need extra for startup (see our running vs surge watts guide). Prices seen in October 2026 and change often. This page contains affiliate links; see our affiliate disclosure.
The Formula Behind This Calculator
Runtime is your power station's usable energy divided by the total power your devices draw. For a rated capacity we apply a standard 85% factor, since converting stored battery energy to AC power loses some as heat; for a measured usable figure we use it as is. This matches the math from our wattage sizing guide.
Usable Wh = rated Wh × 0.85, or the measured figure if you have one.
Example Runtimes
Calculated from independently measured usable energy: Jackery Explorer 1000 v2 (910Wh), Jackery Explorer 2000 v2 (1,710Wh), Bluetti Elite 200 V2 (1.91kWh) and EcoFlow DELTA Pro 3 (3.79kWh).
| Device | 1,000Wh class | 2,000Wh class | Elite 200 V2 | DELTA Pro 3 |
|---|---|---|---|---|
| Full-size fridge (70W average) | 13 hours | 24 hours | 27 hours | 54 hours |
| CPAP, no humidifier (40W) | 23 hours (2.8 nights) | 43 hours (5.3 nights) | 48 hours (6 nights) | 95 hours (11.8 nights) |
| Laptop (65W) | 14 hours | 26 hours | 29 hours | 58 hours |
| Window AC (900W) | 1 hour | 1.9 hours | 2.1 hours | 4.2 hours |
| Space heater (1,500W) | 36 minutes | 1.1 hours | 1.3 hours | 2.5 hours |
Finding Your Device's Actual Wattage
- Check the label or spec plate on the device itself — it's usually printed as "Output: XXW."
- If only amps and voltage are listed, multiply them together (Watts = Volts × Amps).
- Use the running wattage, not the peak or startup wattage listed in some spec sheets.
- When in doubt, round up slightly — a small buffer is safer than an optimistic guess.
For devices with a compressor or motor — fridges, sump pumps, AC units — the number you want is the running wattage, not the brief startup surge. See our running watts vs. surge watts guide for the difference.
What Can Affect Your Real-World Runtime
- Ambient temperature — batteries deliver less usable capacity in cold conditions.
- Battery age and cycle count — capacity gradually declines with use over time.
- Cycling loads — a fridge or AC compressor draws power in bursts, not continuously, so use the average draw (a fridge's EnergyGuide kWh per year divided by 8.76) rather than its running watts.
- AC vs. DC output — charging over USB-C or a 12V port is more efficient than through the AC inverter, so DC-powered devices may run longer than this estimate.
Frequently Asked Questions
How accurate is this runtime calculator?
It is a solid real-world estimate. With a measured usable capacity it uses that figure as is, and with a rated capacity it subtracts about 15% for inverter losses. Actual runtime still varies with temperature, battery age, and whether your device cycles on and off like a fridge or AC compressor.
Why does the calculator reduce rated capacity by 15%?
Converting stored battery energy to AC power loses some energy as heat. Independent tests measured 75% to 93% of rated capacity as usable across 14 stations, so 85% is a realistic middle figure. If you enter a measured usable number instead, choose Measured usable so the loss is not counted twice.
Does this account for a device's startup surge?
No — this calculator estimates total runtime based on continuous running watts, not the momentary startup spike some motors and compressors draw. See our running watts vs surge watts guide if you're checking whether your power station can start a specific device at all.