Figure out exactly how long your portable power station will run any device — from phones and laptops to fridges and CPAP machines. Enter your battery capacity and device wattage, or pick from 50+ common device presets, and get instant, real-world runtime estimates with efficiency loss baked in.
A 1000Wh power station running a 60W device will last approximately 14.2 hours at 85% inverter efficiency. If used 4 hours per day, the battery will last about 3.5 days between charges. We recommend a 1200Wh battery for this load with a 20% safety buffer.
Runtime = (Battery Capacity × Efficiency) ÷ Total Wattage
Recommended size includes a 20% safety buffer for real-world conditions.
Find the watt-hour (Wh) rating of your portable power station. This is usually printed on the box, the unit itself, or in the product specifications. Common sizes range from 200Wh for small units up to 5000Wh+ for large home backup systems. You can use the slider or type in the exact number. We also have quick preset buttons for popular models like Jackery, EcoFlow, Bluetti, and Anker.
Look for the wattage rating on your device's label, power brick, or manual. If you are not sure, use one of our device presets — we have accurate real-world wattage for 50+ common devices including phones, laptops, fridges, CPAP machines, TVs, microwaves, and more. Keep in mind that some devices (like fridges) have both running wattage and surge/startup wattage — use the running wattage for runtime calculations.
If you are running multiple of the same device, adjust the number of devices. For estimating daily or trip-level use, enter how many hours per day you expect to use the device. The calculator will show you both total continuous runtime AND how many days of typical use you can expect.
We default to 85% efficiency, which is a conservative real-world estimate for AC output — this accounts for inverter loss, idle power draw, and real-world conditions. If you are using only DC output (USB charging, 12V car port), select 95% for a more accurate estimate. Older or budget power stations might only be 80% efficient — if in doubt, use 85% as a safe middle ground.
The calculator instantly shows you total runtime in hours, daily energy consumption, days of use, and our recommended battery size with a 20% safety buffer. We recommend sizing up 20–30% from your calculated minimum to account for battery degradation, cold weather, and unexpected usage. Use the recommended size as a starting point when shopping for a power station.
Buying a portable power station is a significant investment — often $500 to $5,000 or more. The last thing you want is to get to your campsite, tailgate, or experience a power outage and realize your station cannot power what you need. Conversely, you do not want to spend thousands on more capacity than you will ever actually use.
Accurate runtime calculations help you:
Avoid overspending on capacity you do not need, or — worse — buying too small and being left without power when you need it most.
Know exactly how long you can go between charges on a camping trip or during an outage. Plan solar charging around your actual consumption.
Two 1000Wh power stations might have very different real-world runtime due to inverter efficiency. Our calculator uses real efficiency factors.
Regularly draining a battery below 10–20% can shorten its lifespan. Knowing runtime helps you recharge before it gets too low.
Many people are surprised by how much (or how little) certain devices draw. A 12V fridge might only use 50–60W average despite having a 100W+ compressor, because the compressor cycles on and off. On the other hand, a simple electric space heater draws 1500W continuously and can drain even a large power station in under two hours.
Pro tip: If you want the most accurate measurement, plug your device into your power station and watch the real-time wattage display (or app) for 10–15 minutes. Write down the average draw, then use that number in our calculator. Nothing beats a real measurement with your specific device and settings.
At its core, calculating power station runtime is simple division. But there are several important factors that people often miss, which is why advertised runtime numbers rarely match real-world experience. Let us break it down step by step.
Runtime (hours) = Battery Capacity (Wh) ÷ Device Wattage (W)
This is the theoretical ideal — 100% efficiency, perfect conditions
Runtime = (Capacity × Efficiency) ÷ Total Draw
This accounts for inverter loss, idle drain, and real conditions
Portable power stations store energy as DC (direct current). When you plug an AC device into the wall outlet, the inverter converts DC to AC — and this conversion wastes 10–15% of the energy as heat. That is why DC output (USB, 12V) gives you more runtime than AC output for the same device.
Lithium batteries perform best between 50–85°F (10–30°C). Below freezing, capacity can drop by 20–40%. Above 100°F (38°C), you get reduced capacity and accelerated battery degradation. If you are camping in cold weather, expect significantly less runtime than the calculator shows.
Every charge cycle slightly reduces battery capacity. NMC batteries retain ~80% capacity after 500 cycles; LFP batteries last 3000–6000+ cycles. A 3-year-old power station used regularly might only have 70–90% of its original capacity left. Most smart stations show actual capacity in the app.
The power station itself uses a small amount of power just to run its display, BMS (battery management system), and inverter idle circuitry. This is usually 2–10W, which is negligible for short-term use but adds up over days. ECO mode can help by turning off unused outputs.
Many devices do not draw constant power. Fridge compressors cycle on and off. Laptops use more power under load than when idle. Phones draw less as they approach full charge. For the most accurate estimate, use the average power draw over time, not the peak or rated wattage.
Scenario: You have a 1024Wh Bluetti EB3A and want to run a 12V car cooler that draws 60W average. You use it 8 hours per day on a camping trip. How long will it last?
Step 1: Start with battery capacity → 1,024 Wh
Step 2: Apply efficiency factor (DC = 95%) → 1,024 × 0.95 = 972.8 Wh usable
Step 3: Divide by device wattage → 972.8 ÷ 60 = 16.2 hours continuous runtime
Step 4: Divide by daily usage → 16.2 ÷ 8 = 2 days of use
Answer: About 16 hours total, or 2 full days of 8-hour use.
With a 20% safety buffer, we would recommend at least 1,200Wh (or about 2 days of solar charging to extend the trip).
Not sure how many watts your device uses? Here is a comprehensive reference table of common devices and their typical power consumption. These are real-world averages — actual wattage varies by brand, model, and settings.
| Device | Typical Wattage | Surge Wattage | Notes |
|---|---|---|---|
| Smartphone charging | 5–18W | — | Fast chargers use more |
| Tablet charging | 10–30W | — | Depends on size |
| Laptop | 30–100W | — | Gaming laptops: 100–200W |
| LED light bulb | 5–15W | — | Equivalent to 40–100W incandescent |
| String lights (LED) | 10–30W | — | Great for camping ambiance |
| CPAP machine | 20–60W | — | With humidifier: 40–80W |
| 12V car cooler / fridge | 40–80W avg | 80–150W | Compressor cycles on/off |
| Full-size refrigerator | 100–200W avg | 500–800W | Needs pure sine wave |
| 32" LED TV | 50–80W | — | Larger TVs use more |
| 55" 4K TV | 80–150W | — | OLED uses more power |
| Router / modem | 5–20W | — | Always-on device |
| Wi-Fi hotspot | 5–15W | — | |
| Portable speaker | 5–20W | — | Depends on volume |
| Drone battery charger | 50–100W | — | Per battery |
| Camera battery charger | 10–30W | — | |
| Electric blanket | 100–200W | — | 12V versions available |
| Coffee maker (pod) | 1000–1500W | — | Short use time |
| Microwave | 600–1500W | — | Short use time |
| Toaster | 800–1500W | — | Short use time |
| Electric grill | 1200–1800W | — | Heavy power draw |
| Space heater | 750–1500W | — | Huge drain — avoid if possible |
| Hair dryer | 1000–1800W | — | Short use time |
| Fan (box/standing) | 30–80W | — | 12V fans are more efficient |
| Air conditioner (portable) | 500–1200W | 1500–3000W | Requires large power station |
| Game console | 50–200W | — | Standby: 5–15W |
Surge wattage note: Devices with motors or compressors (fridges, AC units, pumps) draw a brief surge of 2–5x their running wattage when starting up. Your power station must handle this surge — check the surge/peak rating, not just continuous output. Runtime calculations use running wattage, not surge.
Common questions about power station runtime calculations.
To calculate runtime, divide the power station's battery capacity (in watt-hours, Wh) by the total wattage of your devices, then multiply by the inverter efficiency factor (typically 0.85–0.9 for AC output). The formula is: Runtime (hours) = Battery Capacity (Wh) × Efficiency ÷ Device Wattage (W). For example, a 1000Wh power station running a 100W device at 85% efficiency = 1000 × 0.85 ÷ 100 = 8.5 hours. You can also use our calculator above — just enter your capacity and device wattage for instant results.
Most portable power stations have an inverter efficiency of 85–92% for AC output. DC output (USB, 12V car port) is more efficient at 90–95% because it skips the DC-to-AC conversion step. We use 85% as a conservative real-world estimate for AC devices in our calculator. Pure sine wave inverters tend to be 2–5% more efficient than modified sine wave models. Higher-end stations from EcoFlow, Bluetti, and Goal Zero typically have 88–92% efficiency, while budget brands might be 80–85%.
Runtime estimates are typically accurate within ±10–15% for steady loads. Variables that affect real-world runtime include: ambient temperature (batteries perform worse in extreme cold or heat), battery age and cycle count, device power fluctuations (compressor-based devices like fridges cycle on and off), and whether you're using AC or DC output. Always size for 20–30% more capacity than you think you need as a safety buffer. The most accurate way to know is to test with your actual devices.
Advertised runtime numbers often use ideal lab conditions: perfect room temperature, brand new battery, DC-only loads, and no inverter loss. Real-world factors that reduce runtime include: inverter inefficiency (10–15% loss for AC), battery degradation over cycles, cold weather (can reduce capacity by 20–40% below freezing), phantom/standby loads, and running multiple devices simultaneously. Our calculator uses conservative real-world efficiency factors for more accurate estimates than manufacturer marketing numbers.
For a typical weekend camping trip (2–3 nights), most people need 500–1500Wh depending on gear. Light use (phones, lights, camera charging): 300–500Wh. Medium use (add a CPAP, laptop, or 12V cooler): 1000–2000Wh. Heavy use (full-size fridge, cooking appliances, multiple devices): 2000Wh+. Use our calculator above to add up your specific devices and get a personalized estimate. If you bring solar panels, you can get away with a smaller battery because you will be recharging during the day.
Yes, total runtime is based on total wattage draw. If you run a 50W light and a 100W fridge simultaneously, that is 150W total draw — the same as running a single 150W device. The power station's battery has a fixed amount of energy (watt-hours), and every watt you draw reduces the remaining runtime proportionally. Some devices have surge wattage when starting up (like fridge compressors), which briefly draws more power but does not significantly affect total runtime since surges only last a second or two.
Watts (W) measure the rate of power consumption at any given moment — think of it as the speed of energy flow. Watt-hours (Wh) measure the total amount of energy used over time — think of it as the total distance traveled. A 100W device running for 1 hour uses 100Wh. The same device running for 5 hours uses 500Wh. Power stations are rated in Wh (capacity), while devices are rated in W (draw rate). This is why you can run a low-wattage device for many hours on a single charge, while a high-wattage device drains the battery quickly.
All batteries degrade over charge cycles. Lithium-ion (NMC) batteries typically retain 80% capacity after 500–800 cycles. Lithium iron phosphate (LFP) batteries last much longer — 3000–6000+ cycles to reach 80% capacity. A 5-year-old power station with NMC cells might only have 60–70% of its original capacity, meaning runtime is proportionally reduced. You can check actual capacity in the companion app on most smart power stations. If your runtime has dropped significantly, the battery has likely degraded — this is normal wear and tear, not a defect.
Always use DC output when possible to maximize runtime. DC devices (USB charging, 12V car port) skip the DC-to-AC inverter conversion step, saving 10–15% in efficiency losses. For example, charging your phone via USB is more efficient than using an AC wall charger plugged into the power station. Many 12V appliances like car coolers and CPAP machines can run directly from DC — use the DC output if your power station has one. You can also buy DC versions of many camping appliances specifically for this reason.
We recommend sizing your power station 20–30% larger than your calculated minimum needs. This buffer accounts for: battery degradation over time, unexpected extra device use, colder-than-expected weather, and inaccurate wattage estimates. If you plan to use solar charging to top up during the day, you can reduce the buffer slightly, but it is still wise to have at least 10–15% headroom for peace of mind. Our calculator automatically recommends a battery size with a 20% safety factor built in.