Watt-Hour Calculator for Power Stations
Add your devices to estimate the battery capacity and continuous inverter output you need. The calculator multiplies watts × hours × quantity, divides each load by 0.85 on AC or 0.95 on 12V DC, applies multi-day solar credit, then adds your 25% or 50% safety margin.
Daily net Wh = Σ (watts × hours × quantity) Daily battery Wh = Σ (watts × hours × quantity ÷ 0.85 AC or 0.95 DC) Solar offset = min(solar W × 4 effective hours, daily net Wh) N-day need = max(daily battery Wh × N − solar offset × (N−1), daily battery Wh) Recommended Wh = N-day need × (1 + margin) Results stay in this browser and are not saved. Copy the summary or shareable link to keep them.
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Edit any preset. Results update automatically after 300ms, or use Recalculate.
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Quick-add devices
Trip and charging settings
Frequently asked questions
What's the difference between watts and watt-hours?
Watts measure how fast power flows right now; watt-hours measure the total energy stored. A 60W device running for 10 hours uses 600Wh. Your power station's Wh rating is the tank size, its W rating is how big the tap is.
Why does my power station die faster than the math says?
Three reasons: inverter conversion loses 10–15%, batteries deliver less in the cold, and capacity fades with age. Always size with a 25–50% safety margin.