PUMPHow the numbers are made
Every default on this site is listed here with where it came from. The rule for the whole site: a number you didn't type is a guess, it says so, and you can overwrite it. Verdicts are never adjusted for affiliate relationships.
Fill up — true cost per gallon
true = sign − rebates − card + detour + membership + quality
| Line | How | Source / default |
|---|---|---|
| Sign | What the station posts. Prefilled from the regional weekly average until you overwrite it. | U.S. Energy Information Administration, weekly retail gasoline prices by state, metro and PADD region. Diesel isn't published at metro level; it's estimated from regular plus the current Florida spread. |
| Rebates | Loyalty ¢/gal plus cashback-app ¢/gal, subtracted from the sign. | Program values as published by each brand, typical as of September 2026. They change often. Report a change. |
| Card | Your card's % back, applied to the price after rebates. Zeroed if you pay with the GasBuddy card, which replaces your card. | Card issuers' published rates. |
| Detour | Extra round-trip miles ÷ your MPG × price, plus (extra miles ÷ speed) × what your time is worth, spread across the gallons in one fill. | Defaults: 0 $/hr for time, 30 mph. |
| Membership | Annual warehouse fee ÷ gallons you buy a year. | Costco $65, Sam's Club $50 (basic tiers). |
| Quality | A per-gallon penalty you set for stations that aren't Top Tier certified. Default 5¢. It's the softest number on the site, and it's the one that flips winners — layer 4 shows exactly where. | AAA's independent lab testing found non-Top-Tier gasoline caused 19× more engine deposits after 4,000 simulated miles. A $400 injector cleaning every 60,000 miles ≈ 17¢/gal; every 150,000 miles ≈ 7¢/gal. Top Tier brand list: toptiergas.com. |
| MPG | EPA combined for your trim. "Real-world" toggle applies −12%. | EPA fueleconomy.gov. Real-world figures typically run 10–15% below the label. |
| Gallons per fill | By EPA vehicle class. | Compact 11, midsize 13, large 15, small SUV 14, standard SUV/minivan 18, pickup/van 22. |
Hybrid — annual running cost
gas car = fuel + maintenance + insurance hybrid = fuel (better mpg, + electricity if plug-in) + maintenance + insurance × (1 + change)
| Line | How | Source / default |
|---|---|---|
| Fuel | miles ÷ mpg × gas price, computed separately for the gas car's mpg and the hybrid's EPA combined mpg. For a plug-in, only the gas-share of miles. | EPA fueleconomy.gov. Real-world toggle applies −12%. |
| Electricity (plug-ins only) | Your chosen share of miles on the battery × kWh/100 mi × home electricity rate. The rest of the miles burn gas at the car's hybrid MPG. | EPA charge-depleting kWh/100 mi. Electricity rate: EIA average residential price for your state. Battery-mile share default 60%, editable. |
| Maintenance | ¢ per mile × miles. | AAA Your Driving Costs averages: gas cars ~9.5¢, hybrids ~8¢ — hybrids brake less on the pads but still carry two powertrains to service. |
| Insurance | Your current premium × a % change for the hybrid. | Default +5%. Hybrids usually price close to their gas twin — sometimes a little more for the battery, sometimes nothing. Only a real quote settles it. |
| Incentives | Not applied automatically. | The federal hybrid and clean-vehicle tax credits ended September 30, 2025. Check your state's list for what's left. |
Conventional hybrids and plug-in hybrids are both handled here. Only a full EV picked on this page redirects to Charge up; a full EV, plug-in, or conventional hybrid picked on Charge up redirects here as appropriate.
Charge up — annual running cost
gas car = fuel + maintenance + insurance EV = electricity + maintenance + insurance × (1 + change) + state fee + charger rental
Charge up is for fully electric vehicles only. Plug-in hybrids and conventional hybrids are on the Hybrid page above.
| Line | How | Source / default |
|---|---|---|
| Electricity | miles × kWh/100 mi × (home share × home rate + public share × public rate). | Home rate: EIA average residential price for your state, monthly. Public: network presets — Supercharger ~45¢, Electrify America ~48¢, EVgo ~55¢, Level 2 public ~30¢ — typical mid-2026, editable. |
| Maintenance | ¢ per mile × miles. | AAA Your Driving Costs averages: gas cars ~9.5¢, EVs ~7¢. |
| Insurance | Your current premium × a % change for the EV. | Default +20%. EV premiums commonly run 15–25% higher; only a real quote settles it. |
| Charger | Buy: one-time, shown as payback, not in the annual number. Rent: monthly fee × 12, in the annual number. None: nothing. | Buy default $1,712 (Qmerit 2026 Florida average). Rent default $32/mo (FPL EVolution Home runs $27–36). |
| Solar | Depends on how your utility credits exports. Full retail net metering: charging costs the retail credit you gave up — no change. Net billing: daytime charging costs the export rate; night costs retail. No credit: daytime charging is free. | Default credit type by state: net billing for CA, AZ, HI, UT, ID, NV; full retail elsewhere. Export credit default 7¢. Daytime charging share default 20%. |
| Battery | Shifts up to 90% of its capacity per night from daytime solar into the night charge. Only worth money when exports are credited below retail. Its payback is shown on EV charging alone, honestly. | Default 13.5 kWh, $12,000 installed. Under full-retail net metering its value is outages, and the page says so. |
| Vehicle-to-home | Flags EVs sold with V2H hardware or a documented path to it, and states pack size as home-battery equivalents. | Pack size estimated as range × kWh/100 mi (EPA doesn't publish it). V2H list is conservative; verify the trim. |
| Incentives | Listed for your state, not applied automatically. Enter what you qualify for. | U.S. DOE Alternative Fuels Data Center. The federal clean-vehicle credit ended September 30, 2025; the federal home-charger credit ended June 30, 2026. |
What's deliberately not modeled
- Purchase price, depreciation, financing, resale — Charge up is running cost, not total cost of ownership.
- Price staleness — a posted price can move before you arrive.
- Grade "midgrade" — too few buyers to earn a dropdown row.
Data feeds
- Gas and electricity: EIA Open Data API. Served through this site's own functions with cached responses; direct calls only as a fallback.
- Vehicles: EPA fueleconomy.gov web services.
- Station prices: Google Places API (New),
fuelOptions. Powered by Google. Server-side, cached per ZIP for an hour. - Incentives: NREL / AFDC Laws & Incentives API.
- ZIP to state: a static prefix table, no lookup.