What Size Portable Power Station Do I Need?

The Two Numbers That Matter

Every power station has two critical specs, and you need to understand both:

• Capacity (Wh) tells you how much total energy the battery stores. Think of it like the size of a gas tank. A 1000Wh station stores 1000 watt-hours of energy. This determines how long you can run your devices.
• Output (W) tells you how much power the station can deliver at one time. Think of it like the diameter of the gas line. A 1500W station can power devices totaling up to 1500 watts simultaneously. This determines what devices you can run.

You need to satisfy both requirements. A 3000Wh station with only 300W output has tons of energy but cannot power a microwave. A 300Wh station with 2000W output can run almost anything but only for a few minutes. Most stations are reasonably balanced, but always check both specs.

For a deeper dive into these concepts, see our complete guide to choosing a power station.

Step-by-Step Sizing Method

Follow these four steps to calculate your exact requirements:

Step 1: List Every Device You Want to Power

Write down everything you plan to run. Be specific. Do not just say “kitchen appliances” because a toaster (1200W) and a phone charger (20W) are very different beasts. Include devices you might want to run simultaneously.

Step 2: Find the Wattage of Each Device

Check the label on each device (usually on the back or bottom), the owner's manual, or search online. You need two numbers for each device: running watts and startup surge watts (only applies to devices with motors or compressors like fridges, ACs, and power tools).

Step 3: Calculate Your Daily Watt-Hours

For each device, multiply its wattage by the number of hours per day you expect to use it. Then add everything up:

Step 4: Add a 20% Buffer and Choose Your Capacity

Multiply your daily Wh by the number of days you need power, then add 20% for real-world losses:

The 20% buffer accounts for inverter efficiency losses (10-15%), battery degradation over time, temperature effects on capacity, and the fact that most manufacturers recommend not fully depleting the battery regularly.

Skip the math and use our Runtime Calculator to plug in your devices and get an instant recommendation.

Common Device Wattages

Here is a reference table for the most common devices people want to run on a power station:

Sizing for Common Scenarios

Scenario 1: Camping Weekend (2 Nights, No Solar)

230Wh/day × 2 days × 1.20 buffer = 552Wh minimum. A 500-600Wh station handles this comfortably. With solar panels, you could get by with 300Wh. See our best stations for camping.

Scenario 2: Home Power Outage (4 Hours)

610Wh × 1.20 buffer = 732Wh minimum. A 750-1000Wh station handles a 4-hour outage covering essentials. For longer outages, scale up proportionally or add solar. Check out our best stations for home backup.

Scenario 3: Work from Home During Outage (8 Hours)

950Wh × 1.20 buffer = 1140Wh minimum. A 1000-1500Wh station keeps you productive through a full workday outage. Pro tip: charge your laptop directly via USB-C from the power station to avoid inverter losses, saving 10-15% of capacity.

Scenario 4: CPAP Overnight (8 Hours)

For CPAP without humidifier using a DC adapter, even a 300Wh station handles a full night. With heated humidifier on AC, you need 600-1000Wh. Using a DC adapter is the single biggest thing you can do to reduce power consumption. See our CPAP-specific guide for detailed recommendations.

Capacity Tier Recommendations

Based on the scenarios above, here is how we think about capacity tiers and who each one is best for:

Common Sizing Mistakes

• Ignoring surge wattage. Your fridge might only draw 100W running, but if it surges to 600W on startup and your station maxes out at 500W, it will not work. Always check that the station's surge rating exceeds your highest-surge device.
• Forgetting inverter losses. AC appliances lose 10-15% of stored energy through the inverter. If you calculate needing exactly 1000Wh, buy at least 1200Wh to account for this. DC devices (USB, 12V) avoid this loss entirely.
• Planning for average use, not peak use. Size for your worst-case scenario. If you might need the station for a 48-hour outage, do not size it for 4 hours just because that is more common.
• Not considering temperature. Cold weather reduces lithium battery capacity by 10-30%. If you plan to use your station in winter, size up accordingly.
• Overlooking expandability. If you are unsure about your needs, consider an expandable station. You can start with the base unit and add battery packs later as you learn your actual consumption patterns. Browse our full database to filter for expandable models.

Top Picks by Size Category

Here are top-value stations from each size tier in our database of 106 power stations, sorted by best $/Wh value.

Compact (200-500Wh)

Mid-Range (500-1500Wh)

Large (1500Wh+)

Not sure which is right for you? Use our Runtime Calculator to enter your specific devices and get a personalized recommendation, or try the comparison tool to evaluate models side by side.