What this tool does
The Propane Usage Calculator helps homeowners, RV owners, and property managers estimate how much propane their appliances consume and how long a tank will last. By entering each propane-powered appliance and its daily usage, you get a clear picture of your total consumption in gallons per day and per year, plus the duration a given tank size will provide.
Once you know your consumption, the tool connects to an AI service to retrieve current propane price estimates for your region — giving you a realistic annual fuel budget without guessing at prices that change seasonally and by location.
Whether you're sizing a new tank, budgeting for winter heating, or simply curious about how much your grill costs to run, this calculator gives you accurate, physics-based consumption figures paired with real-world cost context.
How propane is measured
Propane is sold by the gallon and measured by energy content in British Thermal Units (BTU). One gallon of propane contains approximately 91,502 BTU of energy — a physical constant you can rely on regardless of where or when you buy propane.
Appliance manufacturers rate their equipment in BTU per hour (BTU/hr), which tells you how fast the appliance burns fuel at full output. A furnace rated at 80,000 BTU/hr running for 8 hours consumes 640,000 BTU per day, which equals about 7 gallons (640,000 ÷ 91,502 ≈ 6.99).
**Key conversion facts:** - 1 gallon propane = 91,502 BTU - 1 lb propane = 21,591 BTU - A 20 lb cylinder holds approximately 4.7 gallons
Tanks are measured in either pounds (small cylinders) or gallons (larger residential and commercial tanks). For safety, larger tanks are only filled to 80% capacity, so a 250-gallon tank holds about 200 usable gallons.
Understanding BTU ratings
Every propane appliance has a BTU/hr rating that indicates its maximum heat output or fuel consumption rate. This rating is found on the appliance's data plate, in the owner's manual, or sometimes printed on the burner assembly itself.
**Typical BTU/hr ratings by appliance:** - **Furnace**: 40,000–150,000 BTU/hr (typical: 80,000) - **Water Heater**: 30,000–50,000 BTU/hr (typical: 40,000) - **Fireplace**: 20,000–60,000 BTU/hr (typical: 35,000) - **Grill**: 10,000–60,000 BTU/hr (typical: 30,000) - **Generator**: 10,000–30,000 BTU/hr (typical: 20,000) - **Range / Stove**: 8,000–60,000 BTU/hr (typical: 30,000) - **Dryer**: 20,000–30,000 BTU/hr (typical: 22,000) - **Pool Heater**: 100,000–400,000 BTU/hr (typical: 150,000)
Note that most appliances don't run at full output continuously. A furnace cycles on and off depending on thermostat settings and outdoor temperature. A grill's actual consumption depends on how many burners are open and at what level. Use your best estimate for daily hours of active operation, not just hours the appliance is turned on.
Tank sizing guide
Choosing the right tank size balances upfront cost, delivery frequency, and usage needs. Here is a practical guide:
**20 lb cylinder (~4.7 gal)**: Standard grill tank. Good for portable use, seasonal grilling, and camping equipment. Typically lasts 18–20 hours on a standard grill burner.
**100 lb cylinder (~23.6 gal)**: Suitable for lighter home use — a standby generator, a fireplace, or a small cabin's water heater. Requires less frequent refills than a 20 lb tank.
**250-gallon tank (200 gal usable)**: The most common size for homes with a single propane appliance such as a furnace or water heater. Suitable for moderate climates where propane isn't the primary heating fuel.
**500-gallon tank (400 gal usable)**: Standard for homes that rely on propane as the primary heating source. Typically requires 2–4 fills per year in cold climates.
**1,000-gallon tank (800 gal usable)**: For large homes, farms, commercial applications, or properties with multiple high-BTU appliances. Often used where delivery access is difficult or deliveries need to be infrequent.
A general rule of thumb: size your tank so you receive no more than 2 deliveries per winter season. This minimizes delivery fees and reduces the risk of running out.
Propane safety tips
Propane is a safe and efficient fuel when handled properly. Keep these safety guidelines in mind:
- **Smell for leaks**: Propane has a distinct rotten egg or skunk-like odor added intentionally. If you smell gas, do not operate any switches, open windows, leave the area, and call your propane supplier. - **Never store cylinders indoors**: Always keep tanks outdoors in a well-ventilated area away from heat sources and ignition points. - **Keep the 80% rule in mind**: Never overfill a propane tank. Tanks should only be filled to 80% of capacity to allow for thermal expansion. - **Schedule annual inspections**: Have your propane system inspected by a certified technician each year before heating season. - **Know your shutoff valve**: Locate your main shutoff valve and make sure all household members know how to use it. - **Monitor tank levels**: Don't let your tank run completely empty — air and moisture can enter an empty tank and require professional purging before refill.
How to use
1. Add each propane appliance you use by selecting its type from the dropdown menu 2. Adjust the BTU/hr rating to match your specific appliance (check the data plate or manual) 3. Set the daily hours of usage using the slider — estimate how many hours per day the appliance actively runs 4. Add additional appliances using the "+ Add Another Appliance" button 5. Select your tank size from the dropdown menu 6. Click "Calculate Consumption" to see gallons per day, gallons per year, and how long your tank will last 7. Enter your region or state and click "Get Cost Estimate" to receive an AI-powered estimate of current propane prices and your annual fuel budget
FAQs
**Q: How accurate are the consumption estimates?** A: The consumption calculations use standard propane physics: 91,502 BTU per gallon and your appliance's BTU/hr rating. The accuracy depends on how closely your entered values match your actual appliance and usage patterns. Most people find the estimates within 10–20% of actual usage.
**Q: Why are propane prices obtained from AI instead of being shown directly?** A: Propane prices fluctuate significantly by region, season, and market conditions — often by \$1 or more per gallon between summer and winter, or between rural and urban areas. Hardcoded prices would quickly become outdated and misleading. The AI service uses current market knowledge to provide region-appropriate estimates.
**Q: How do I find my appliance's BTU rating?** A: Look for a data plate or rating label on the appliance itself — usually on the back, inside a door panel, or on the burner assembly. The BTU/hr rating is almost always listed. You can also check the owner's manual or search the model number online.
**Q: Should I use the maximum BTU rating or something lower?** A: Use the appliance's rated BTU/hr for the calculation, but be realistic about daily hours. A furnace rated at 80,000 BTU/hr doesn't run continuously — it cycles on and off. Estimating 6–10 hours of active run time per day in cold weather is typically reasonable for a furnace. A grill used for cooking may only actively burn for 1–2 hours per use.
**Q: What is the 80% fill rule for large tanks?** A: For safety, propane tanks larger than 100 lb are only filled to 80% of their listed capacity. This leaves room for the liquid propane to expand when temperatures rise. The calculator already accounts for this: a 250-gallon tank shows 200 usable gallons, a 500-gallon tank shows 400, and so on.
**Q: How long does a 20 lb grill tank last?** A: A standard 20 lb grill tank holds about 4.7 gallons of propane. A typical two-burner grill running all burners at medium uses about 1.5 lb (roughly 0.35 gal) per hour. At that rate, a full 20 lb tank lasts approximately 13–14 hours of grilling time. The calculator will give you a precise estimate based on your grill's specific BTU rating and usage hours.
**Q: Can I use this calculator for an RV?** A: Yes. RVs commonly use propane for furnaces, water heaters, refrigerators, and stoves. Add each appliance separately with its BTU rating and estimated daily usage to see your total RV propane consumption and how long your onboard tanks will last.
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