{ "slug": "avgas-vs-mogas-savings", "title": "Avgas vs Mogas Savings Calculator", "heading": "Avgas vs Mogas Fuel Savings Calculator", "category": "financial", "url": "https://www.revenuelab.fyi/toolbox/avgas-vs-mogas-savings", "summary": "Annual fuel savings from an autogas STC versus 100LL, net of any premium.", "description": "Automotive gas (mogas) with an ethanol-free STC often runs $1.50-3.00/gallon cheaper than 100LL avgas at airports that offer it, but not every engine is approved and not every airport sells it, so you often need to truck fuel in or drive to a self-serve pump. This calculator nets the per-gallon savings against your annual fuel burn to show real annual savings, while flagging that mogas isn't a free lunch — it typically has a shorter usable shelf life and stricter octane and ethanol-content requirements than 100LL.", "formula": "Annual savings = annual gallons burned × (avgas price − mogas price) − any extra hauling/storage cost.", "dateModified": "2026-09-30", "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=avgas-vs-mogas-savings", "inputs": [ { "id": "hoursYear", "label": "Hours flown per year", "kind": "number", "hint": null, "default": 100, "unit": null, "min": 1, "max": null }, { "id": "burnRate", "label": "Fuel burn", "kind": "number", "hint": null, "default": 8, "unit": "gal/hr", "min": 1, "max": null }, { "id": "avgasPrice", "label": "100LL price", "kind": "number", "hint": null, "default": 6.3, "unit": "$/gal", "min": 0, "max": null }, { "id": "mogasPrice", "label": "Ethanol-free mogas price", "kind": "number", "hint": null, "default": 4.1, "unit": "$/gal", "min": 0, "max": null }, { "id": "extraCost", "label": "Extra hauling/storage cost per year", "kind": "number", "hint": null, "default": 200, "unit": "$", "min": 0, "max": null } ], "outputs": [ { "id": "netSavings", "label": "Net annual savings switching to mogas", "format": "currency", "hint": null, "primary": true }, { "id": "grossSavings", "label": "Gross fuel savings before extra costs", "format": "currency", "hint": null, "primary": false }, { "id": "gallons", "label": "Annual gallons burned", "format": "number", "hint": null, "primary": false }, { "id": "perHourSavings", "label": "Net savings per flight hour", "format": "currency", "hint": null, "primary": false } ], "worked_example": { "inputs": [ "Hours flown per year: 100", "Fuel burn: 8 gal/hr", "100LL price: 6.3 $/gal", "Ethanol-free mogas price: 4.1 $/gal", "Extra hauling/storage cost per year: 200 $" ], "outputs": [ "Net annual savings switching to mogas: $1,560", "Gross fuel savings before extra costs: $1,760", "Annual gallons burned: 800", "Net savings per flight hour: $15.60" ] }, "how_to": { "title": "How to use this", "steps": [ "Enter hours flown per year.", "Enter fuel burn (gal/hr).", "Enter 100ll price ($/gal).", "Enter ethanol-free mogas price ($/gal).", "Enter extra hauling/storage cost per year ($).", "Read your net annual savings switching to mogas on the right — it updates as you type.", "Hit Share to keep the scenario or send it to someone." ] }, "scenarios": [ { "name": "Conservative", "description": "Lower-end numbers — what if things land soft?", "values": { "hoursYear": 60, "burnRate": 4.8, "avgasPrice": 3.78, "mogasPrice": 2.4599999999999995, "extraCost": 125 } }, { "name": "Typical", "description": "Defaults — the most common real-world setup.", "values": { "hoursYear": 100, "burnRate": 8, "avgasPrice": 6.3, "mogasPrice": 4.1, "extraCost": 200 } }, { "name": "Ambitious", "description": "Higher-end numbers — what if things really pop?", "values": { "hoursYear": 160, "burnRate": 12.8, "avgasPrice": 10.08, "mogasPrice": 6.56, "extraCost": 325 } } ], "limitations": [ "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.", "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.", "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant." ], "faq": [ { "q": "Does every engine qualify for a mogas STC?", "a": "No — STCs from companies like Petersen Aviation and EAA typically cover specific low-compression engines like the Continental O-200 and certain Lycoming O-320/O-360 variants at lower compression ratios, but higher-compression, turbocharged, or fuel-injected engines are frequently excluded. Confirm your exact engine and airframe combination is on the STC's approved model list before assuming eligibility." }, { "q": "Why does mogas need to be ethanol-free specifically?", "a": "Ethanol absorbs atmospheric moisture and can cause phase separation in the tank, is more corrosive to certain fuel system seals and components not designed for it, and generally isn't approved under aviation mogas STCs. E0 (zero-ethanol) premium unleaded is the fuel that must be sourced, which is less commonly available at retail pumps than E10." }, { "q": "What's the shelf-life tradeoff?", "a": "Mogas typically degrades faster than 100LL, especially once exposed to air and temperature swings in a partially-filled tank, with some guidance suggesting use within 60-90 days versus 100LL's longer stable shelf life. Aircraft that sit for weeks between flights are poor candidates for mogas since stale fuel raises its own set of engine problems." }, { "q": "Is trucking mogas to the airport worth the hassle?", "a": "If your airport doesn't sell mogas on the field, you're hauling fuel in cans or a fuel trailer, which adds real labor time and a small safety/spill risk that some pilots decide isn't worth the savings, especially at low annual hours where total savings might only be a few hundred dollars. High-hour flyers at airports without on-field mogas still often find it worthwhile." } ], "related": [ "https://www.revenuelab.fyi/toolbox/fuel-endurance-range", "https://www.revenuelab.fyi/toolbox/aircraft-ownership-cost-per-hour" ], "license": "CC-BY-4.0", "citation": "RevenueLab — Avgas vs Mogas Savings Calculator (https://www.revenuelab.fyi/toolbox/avgas-vs-mogas-savings)" }