Portable Power Station Size Calculator
Estimate required Wh and screen continuous / surge watts for Jackery-, EcoFlow-, and Bluetti-class stations—instant sizing for outage and camping loads.
Calculator
Scenario: pick a use case and check devices (energy = Σ W×h). Quick: edit continuous watts × hours directly. Advanced: η, buffer, surge.
About this calculator
Screens portable power station Wh and watt ratings from load and hours. It is not a UPS kVA selector and not a generator sizing tool. Decide UPS vs station in portable power vs UPS; for IT bridge minutes use UPS runtime. Browse the backup power calculator hub or the UPS calculator hub.
Calculation Results
≈ 1067 Wh usable energy needed
Minimum screen: ≥1067 Wh · continuous ≥200 W · surge ≥200 W, subject to the OEM capacity and rating definitions.
Assumptions: constant average watts and user-entered η/buffer. Confirm whether the OEM publishes nominal or usable Wh; do not count hidden BMS reserve twice. Temperature, rate effects, and cutoffs are not modeled.
Continue Your Calculation
Need UPS bridge minutes for PCs or networking instead of hour-scale Wh? Continue in UPS Runtime.
Planning disclaimer
Screening estimate only. Confirm continuous watts, surge, usable Wh, waveform (pure sine), and recharge options on the manufacturer datasheet. Whole-home multi-circuit backup usually needs a generator and listed transfer method—not a suitcase station alone.
Wh quick reference (η 0.9 · 20% buffer)
Required Wh ≈ (W × hours ÷ 0.9) × 1.2. Open a row to load the calculator.
| Load | Hours | ≈ Required Wh |
|---|---|---|
| 8 h | ≈ 1067 Wh | |
| 4 h | ≈ 1067 Wh | |
| 6 h | ≈ 1250 Wh | |
| 3 h | ≈ 2000 Wh | |
| 12 h | ≈ 1280 Wh |
Formula & explanation
Whrequired = (Wcontinuous × hours ÷ η) × (1 + buffer)
Then screen a commercial tier whose nameplate Wh ≥ Whrequired and continuous watts ≥ Wcontinuous, with surge ≥ peak start watts.
Why no PF? This tool sizes energy (Wh) and AC continuous watts for consumer stations. Power factor belongs in UPS capacity (kVA) and generator sizing—different decision.
- W — simultaneous running watts (nameplate or measured).
- hours — planned runtime at that average load.
- η — inverter / conversion efficiency (≤ 1).
- buffer — documented user assumption; do not double-count reserve already excluded from usable Wh.
Example: 200 W × 4 h ÷ 0.9 × 1.20 ≈ 1067 Wh. The selected product must meet or exceed this energy screen and separately meet the continuous and surge watt requirements.
Shortest chain: load watts → Wh screen (this page) → compare vs UPS in portable power vs UPS → IT minutes in UPS runtime → optional generator size for multi-circuit outages.
What can common watt ratings run?
PAA-style guide: continuous rating limits what you can plug in; Wh limits how long.
| Continuous rating | Typical loads | Not ideal alone |
|---|---|---|
| ~300–500 W | Phones, Wi-Fi, LED lights, laptop | Hair dryer, space heater, large microwave |
| ~1000 W | TV, small fridge (check surge), CPAP, camping kit | Whole-home HVAC, EV charging, well pump |
| ~2000 W | Multiple appliances, induction hot plate (short bursts) | Central AC, dryer, continuous high heat |
| Generator path | Multi-circuit / whole-home via transfer switch | Suitcase station as sole whole-home source |
Frequently Asked Questions
How do I size a portable power station?
Wh ≈ (W × hours ÷ η) × (1 + buffer). Example: 200 W for 4 h at η 0.9 with 20% buffer ≈ 1067 Wh. Then match continuous and surge watts on the datasheet.
What size portable power station do I need?
Sum simultaneous watts, multiply by hours, divide by the applicable path efficiency, and apply a documented buffer. Select only a product whose stated Wh basis, continuous watts, and surge watts each meet the calculated requirement.
What will a 1000W portable power station run?
Loads at or under 1000 W continuous (lights, laptop, TV, many small fridges). Runtime still depends on Wh: 1000 Wh at 200 W and η 0.9 ≈ 4.5 h before buffer.
Is a power station the same as a UPS?
No. UPS = short clean bridge for IT; station = hour-scale Wh. See portable power vs UPS.
Do I need power factor here?
No for Wh screening. Use UPS capacity or generator size when you need kVA.
How big a power station for one camping night?
Example: LED 10 W×4 h + fridge 80 W×10 h + phone 20 W×3 h → Σ energy 900 Wh. At η 0.9 and 20% buffer: Wh ≈ 1200 → shop the 1000–1200 Wh class and confirm surge for the fridge compressor.
How do I estimate fridge energy use?
Use average running watts × hours (duty cycle), not nameplate start watts, for Wh. Enter compressor surge separately so the inverter peak rating is checked.
How long will 500 W continuous last?
Runtime still depends on Wh. Example: a 1000 Wh pack at 500 W and η 0.9 lasts roughly 1000×0.9÷500 ≈ 1.8 h before buffer—raise Wh or lower load for longer nights.