Device
Choose how the device connects. Watts alone cannot confirm USB/DC protocol compatibility.
Energy use
W is power at a moment; Wh is energy over time.
Use only when watts describe the device while on.
Output check and source
Capacity and output planning
What size portable power station do you need?
Add your devices and how long you will use them. Estimate battery capacity, check output requirements, and compare suitable power stations.
Step 2 · Check the requirements
Results
Your plan summary will appear here.
- Add each device and its time in this plan.
- Review the editable assumptions.
- Choose Calculate requirements.
No personalized result is shown until then.
Inputs changed — recalculate.
Interpret the answer
How the estimate works: four numbers matter
A power station can store enough energy and still be the wrong fit. Read the result as four related checks, each answering a different question.
Delivered energy
Watt-hours used by the equipment itself. This is the sum of every active device before conversion loss and inverter overhead.
Battery-side energy
Energy the battery must supply after AC, USB, and DC efficiencies plus AC idle draw are included. It will normally exceed delivered energy.
Nominal capacity
The nameplate capacity needed for the selected starting charge, stopping reserve, and health factor. These settings are applied once, not stacked with a hidden depth-of-discharge penalty.
Output demand
The watts devices may draw at the same time. Continuous output, startup demand, and USB/DC connection limits are separate from battery capacity.
Better inputs, better estimate
Measure the loads that can surprise you
A charger label often states a maximum, not typical consumption. Refrigerators, freezers, fans, and other controlled loads switch on and off. Computers change power with workload. For those devices, a plug-in energy meter observed under representative use is usually more useful than a single label wattage.
Use measured daily energy when you have a 24-hour kWh reading. Use already-averaged watts when a meter or monitoring system gives a reliable average for the planned activity. Use operating watts and hours for steady devices or when you know the on-cycle power and a defensible cycling fraction.
Learn how to measure appliance electricity use →Start with the real use case
Practical planning paths
The same battery behaves very differently across a workday, an overnight camping load, and a compressor-based appliance. These guides show what to enter and which uncertainty deserves attention.
Remote work
Plan an eight-hour work session
Laptop, display, network gear, route choice, and useful margin.
Open the work-session guide →CampingBuild a weekend energy budget
Separate always-on cooling from lighting and occasional charging.
Open the camping guide →Home backupPlan for a refrigerator
Use daily energy for capacity and separate compressor startup checks.
Open the refrigerator planner →What if no catalog model matches?
That is a useful result. It may mean the plan requires more stored energy, more continuous AC output, or better startup and connection evidence than the current catalog can support. Do not treat a near match as compatible simply because it is available to buy.
First check whether every device really needs to run in the same window. Then verify high-energy rows and consider whether a device can use direct USB or DC power instead of running the AC inverter. If the requirement remains high, compare your result with the specifications of a candidate model. The runtime calculator accepts its capacity even when the product is not in the catalog.
Browse source-linked power stations or estimate runtime for a station you already own.
The capacity relationship
device energy ÷ route efficiency + idle energy
then
battery-side energy ÷ usable charge fraction
The result panel substitutes your actual route totals and assumptions. See the methodology for validation rules and formula versioning.
Common planning questions
Is a 1,000 Wh station the same as 1,000 W?
No. Watt-hours describe stored energy; watts describe power at a moment. A station needs enough Wh for the duration and enough W for simultaneous running and startup demand. Learn more in watts versus watt-hours.
Why does the calculator suggest more Wh than my devices use?
Conversion is not lossless, the AC inverter may consume energy while enabled, and your selected reserve leaves part of nominal capacity unused. Battery health can reduce the assumed remaining capacity too. Each factor is visible and editable under Advanced settings.
Can this tell me whether a refrigerator will start?
Only when both the appliance startup demand and the station's surge magnitude and compatible duration are documented. Otherwise the startup result remains unknown. A daily kWh reading cannot reveal instantaneous compressor startup demand.
Does a solar wattage match prove the panels are compatible?
No. Wattage is only one limit. Voltage range, current, polarity, connectors, and the station's input rules also matter. The solar charging estimator models energy only and does not provide wiring instructions.
Important limits
This is a simplified planning model. It does not provide medical/life-support assurance, guaranteed outage coverage, whole-home design, transfer-switch guidance, mains or solar wiring instructions, or weather forecasts.