Free Jobsite Tools
Jobsite Power Calculator & Sizing Tools for Contractors
Use the jobsite power calculator below to size your power station from your actual tool list — not a generic wattage estimate. Get the capacity, inverter spec, and solar panel count your operation needs before you buy.
How to Use These Tools
Start with the Jobsite Power Calculator to size your station from your real tool draw. Move to the Battery Runtime Calculator to confirm your chosen unit survives a full shift. Finish with the Solar Panel Calculator to verify your array can top up the battery before the next day starts.
Why These Tools Exist
Most contractors size their power station by gut feel — and end up either underpowered mid-shift or hauling 40 lbs of battery they don’t need. These calculators work from your actual tool list, your site’s peak sun hours, and real inverter efficiency figures. The output is a spec floor, not a marketing estimate.
Calculation Standards Used
All calculations use U.S. Department of Energy peak sun hour data and a 0.85 AC inverter efficiency factor. Surge multipliers follow NEC guidelines for motor-driven tools — 3–5× running wattage for startup loads. Once you have your numbers, use the Gear Lab buying guides to match specs to specific models.
Load · Runtime · Solar
Jobsite Power Calculator
Select your tools, set quantities, and estimate the power station capacity, inverter output, and solar panel count your jobsite may need.
Open Calculator →
Load · Autonomy · Size
Battery Runtime Calculator
Calculate the battery bank size for off-grid operations based on daily energy use, runtime needs, and recharge cycle.
Open Calculator →
Load · Solar · Panels
Solar Panel Calculator
Size a solar array for a fixed installation based on daily consumption, peak sun hours, and panel efficiency.
Open Calculator →
Frequently Asked Questions
How accurate is the jobsite power calculator?
The jobsite power calculator uses manufacturer-rated running wattage and standard NEC surge multipliers for each tool type. Real-world results vary based on battery age, ambient temperature, and actual tool load — so all recommendations include a 20% capacity buffer. Treat the output as a spec floor, not a ceiling. If you’re running tools continuously at high draw, size up to the next capacity tier.
What is the difference between running watts and surge watts?
Running watts is the continuous draw a tool needs while operating. Surge watts is the startup spike — motor-driven tools like circular saws, compressors, and pumps pull 3–5× their running wattage for the first half-second. Your power station’s inverter must handle the surge, not just the continuous load. The jobsite power calculator accounts for both and sizes the inverter spec accordingly.
Can I run multiple tools at the same time?
Yes — the load calculator is built for simultaneous tool use, not sequential. Select every tool you expect to run at the same time during peak load. The calculator totals your continuous draw and identifies the highest single surge load, then sizes the station to handle both without tripping the inverter.
How many solar panels do I need to recharge a power station on site?
Panel count depends on your battery capacity and available peak sun hours. A 2,000Wh station typically requires 400–600W of solar input to recharge fully in one day across 4–5 peak sun hours. Use the Solar Panel Calculator above to enter your specific station capacity and daily energy use — it outputs the minimum panel count and array wattage for your location.
Which power station should I buy after using the calculator?
Once the jobsite power calculator gives you a minimum capacity and inverter spec, head to the Comparison Lab to match those numbers against specific models from EcoFlow, Bluetti, and Jackery. For use-case buying guidance, the Gear Lab covers contractor-specific guides ranked by jobsite type and load profile.
Know your numbers. Now find the right station.
Match your calculator output to specific models in the Comparison Lab, or browse contractor buying guides in the Gear Lab.