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Run the numbers on solar – from power stations to balcony panels
How long does your storage last, what does your panel deliver, and when has the purchase paid for itself? These calculators show consumption, output, balance, off-grid days, charge time and payback – with a step-by-step calculation.
- solar output per day at 200 W and 4 sun hours
- 600 Wh
- a 1,000 Wh power station lasts without sun at 685 Wh consumption
- 1.3 days
- until an $800 balcony solar kit has paid for itself
- 7.8 years
What the calculator gives you
Five results every off-grid plan needs – live, with a step-by-step calculation.
- Total consumption per dayAll devices with power and runtime added up – from presets or your own values.
- Solar output per dayPanel power × sun hours × 0.75 system efficiency – realistic instead of the data sheet value.
- Net balanceSurplus or deficit per day – and how much panel you'd need for an even balance.
- Off-grid daysHow many days and hours the battery or power station lasts without sun – and with solar.
- Charge timeHow long the panel needs to fill the empty storage – in sun hours and days.
Three steps to your result
- 1
Pick your loads
Cooler, laptop, lights, coffee maker – from the preset list or with your own wattage and runtime.
- 2
Enter solar and storage
Panel power, sun hours via slider and the capacity of your power station or battery in Wh.
- 3
Read and share the result
Balance, off-grid days and charge time appear instantly. Expand the calculation, copy the result or share it as a link.
The calculators
Every calculator shows the formula, an example and the calculation steps.
- Solar & storage
Solar & off-grid calculator
Calculate daily consumption, solar output, net balance, off-grid days and charge time of your power station or battery with a solar panel – for camping, tiny houses, balcony solar and off-grid living.
Open calculator - Balcony solar
Balcony solar
Calculate the annual output, self-consumption, bill savings and payback period of a plug-in balcony solar system – with orientation, shading, storage and your own electricity price.
Open calculator - Solar & storage
Power station size
Work out which power station fits your devices: required capacity in Wh, continuous output and surge power in W – with device presets, reserve and solar recharging.
Open calculator - Solar & storage
Off-grid system
Size your off-grid system: required solar power, battery capacity in Ah, charge controller current and inverter – based on the design month of your usage period.
Open calculator - Backup power
Backup power
Calculate how long your storage bridges a power outage – in three levels from essentials to full comfort, with heating pump, refrigerator and optional solar recharging.
Open calculator
Who the calculator is for
- Campers and van lifeIs the folding panel enough for the cooler and laptop at the campsite?
- Tiny houses and cabinsHow big do panel and storage need to be for lights, router and fridge?
- Balcony solar with batteryHow fast is the battery full and how long does it cover the base load?
- Off-grid and backup powerHow many days can you go without the grid – even with three overcast days?
Calculators by category
Each category groups the calculators for one topic.
Why OffgridCalc?
- Transparent: every calculator shows the formula, the calculation steps and the assumptions made.
- Realistic: system efficiency, usable capacity and real runtimes instead of data-sheet optimism.
- Private: everything is calculated in your browser. Your inputs never leave your device.
- Honest: results are estimates – where weather, device data or standards decide, we say so clearly.