What Size Generator Do I Need?
Select your appliances and get exact wattage requirements. Running watts, starting surge, and recommended generator sizes.
Calculate Generator Size
33 Free Calculators
Emergency Preparedness Calculators
Stop guessing and start calculating. Get precise, actionable numbers based on official FEMA, CDC, and Red Cross guidelines. Your data stays in your browser.
MOST SEARCHED
Generator & Power Calculators
Our most popular tools. Answer the questions everyone asks during power outages.
How Long Will My Generator Last?
Enter fuel capacity and load to calculate runtime. Plan fuel storage for 3, 7, or 14-day power outages.
Calculate Generator RuntimePower Station Runtime Calculator
How long will your Jackery, Bluetti, or EcoFlow last? Calculate battery backup runtime for any device combination.
Calculate Battery RuntimePropane Tank Runtime Calculator
How long will a 20lb propane tank last? Calculate runtime for generators, heaters, stoves, and grills.
Calculate Propane RuntimeSolar Recharge Time Calculator
How long to charge your power station with solar? Calculate realistic charging times based on panel size and conditions.
Calculate Solar Charge TimeOff-Grid Solar Calculator
Design a complete off-grid solar system. Calculate panels, batteries, and inverter size for your power needs.
Design Solar SystemUPS / Battery Backup Sizing
What size UPS do you need for your computer? Calculate VA rating and runtime for home office and network equipment.
Size Your UPSWhole Home Battery Calculator
Size your home battery backup system. Calculate how many Tesla Powerwalls, Generac PWRcells, or portable power stations you need.
Calculate Battery SizeWhole House Generator Calculator
What size standby generator do you need? Calculate kW requirements for Generac, Kohler, and other home standby generators.
Calculate Standby GeneratorPower Runtime Calculator
How long will your battery backup run your appliances? Calculate runtime with multiple devices and solar input.
Calculate Power RuntimeFuel Storage Calculator
How much fuel to store for emergencies? Calculate gasoline, diesel, or propane needs with safety guidelines.
Calculate Fuel StorageHeating Fuel Calculator
How much heating fuel do you need? Calculate propane, kerosene, or wood requirements for winter emergencies.
Calculate Heating FuelLighting Runtime Calculator
How long will your emergency lighting last? Calculate runtime for flashlights, lanterns, and battery-powered lights.
Calculate Lighting Runtime
ESSENTIALS
Water, Food & Supplies
The foundation of emergency preparedness. Calculate exactly what your household needs to survive.
Water Storage Calculator
Calculate gallons needed based on family size, climate, and duration. Water is your #1 survival priority.
Calculate Water NeedsWater Purification Calculator
Calculate purification supplies needed: bleach, tablets, or filter capacity for treating water sources.
Calculate PurificationRainwater Collection Calculator
Calculate how much rainwater you can collect from your roof. Size your collection system for your needs.
Calculate CollectionFood Storage Calculator
Determine calories and pounds of food by category. Complete nutritional requirements for long-term storage.
Calculate Food NeedsFreeze-Dried Food Calculator
Calculate how much freeze-dried food to store. Compare to regular food storage with cost analysis.
Calculate Freeze-DriedSurvival Calorie Calculator
Calculate exact caloric needs during emergencies based on body composition, activity, and climate.
Calculate CaloriesEmergency Kit Calculator
Build a complete, prioritized supply checklist customized for your household and local disaster risks.
Build Kit ChecklistSanitation Supplies Calculator
Calculate toilet paper, hygiene supplies, and waste management needs for extended emergencies.
Calculate Sanitation
MEDICAL
First Aid & Medical
Plan your medical supplies for when professional help isn't available.
First Aid Kit Calculator
Build a comprehensive medical kit scaled to your family. Includes trauma options and expiration tracking.
Build First Aid KitMedication Stockpile Calculator
Plan OTC and prescription medication supplies. Includes storage tips and expiration tracking.
Plan Medication Supply
EVACUATION
Bug-Out & Mobility Calculators
When you need to move fast, know your limits and optimize your gear.
Bug-Out Bag Weight Calculator
Ensure your go-bag isn't too heavy. Calculate weight as percentage of body weight with optimization tips.
Optimize Pack WeightEvacuation Time Calculator
How long will it take your family to evacuate? Calculate realistic timelines based on preparedness level.
Calculate Evacuation TimeVehicle Emergency Kit Calculator
Build the right car emergency kit for your vehicle and driving conditions. Seasonal adjustments included.
Build Vehicle KitCommunication Range Calculator
What radio do you need? Calculate range requirements based on terrain and distance to family members.
Calculate Radio Range
SPECIALIZED
Shelter, Pets & Budgeting
Address specific needs for your household's unique requirements.
Shelter-in-Place Calculator
Calculate supplies needed to shelter in place. From 72 hours to 30 days, plan for any duration.
Calculate Shelter SuppliesShelter Capacity Calculator
Determine how many people can shelter in your space and supplies needed for extended stays.
Calculate CapacityPet Emergency Supplies
Don't forget your furry family members. Calculate food, water, and supplies for dogs, cats, and more.
Calculate Pet SuppliesEmergency Budget Calculator
Plan your preparedness spending. See cost breakdowns and prioritize purchases by importance.
Plan Your BudgetEmergency Savings Calculator
How much emergency cash should you have? Calculate savings goals based on your expenses and risk factors.
Calculate Savings GoalPreparedness Score
How prepared are you? Take our assessment to get a preparedness score and personalized recommendations.
Get Your ScoreNot Sure Where to Start?
Start with the basics: water is your most critical survival resource, and power keeps your essentials running. Pick one and begin.