Gaslo helps you estimate fuel costs instantly so you can plan smarter, drive farther, and spend less.
You know that moment — you pull up to the gas station, the teller asks how much you want on the pump, you give them a number, and then you start filling up… only to watch the gauge stop short of full because you didn't put enough on. So you walk back inside, embarrassed, to add a few more dollars.
That happened to me one too many times. Every fill-up turned into guesswork. Was it $30? $40? Half a tank? Three-quarters? I'd round up to be safe and overpay, or round down and come up short.
So I built Gaslo. Type in your tank size, how much fuel is left, and the price per gallon — and you get the exact amount you need, before you ever step inside the gas station. No more being short. No more overpaying. No more awkward walks back to the counter.
It's a small problem. But it adds up — and now you don't have to think about it anymore.
The fill-up calculator is Gaslo's most popular tool. It tells you the exact dollar amount to put on the pump before you even walk inside. Here's how to use it:
Step 1: Select your vehicle from the built-in database, or type in your tank size manually (in gallons). Most cars range from 10 to 26 gallons — you can find yours in the owner's manual or on the inside of your fuel door.
Step 2: Tell Gaslo how much fuel is left in your tank. You can do this three ways: enter your miles-to-empty reading from your dashboard, enter your trip odometer miles since last fill-up, or just tap your current gauge position (E, ¼, ½, ¾, or F).
Step 3: Enter today's gas price per gallon. You can use the live national average that Gaslo pulls automatically from the U.S. Energy Information Administration (EIA), or type in the price you see at your local station.
Hit Calculate Fill-Up and Gaslo instantly shows you the exact dollar amount to put on the pump, the number of gallons you need, and your cost per gallon. That's it.
Heading on a road trip or just want to know what your commute costs in gas? The trip calculator gives you an instant estimate. Enter your trip distance in miles, your vehicle's MPG (or look it up with the built-in EPA vehicle picker), and the current gas price. Gaslo calculates exactly how many gallons you'll burn and what it will cost — before you leave the driveway.
This is especially useful for long trips. A 500-mile drive in a vehicle getting 30 MPG at $3.50/gallon costs about $58.33 in fuel. Knowing that in advance helps you budget better and decide whether to stop to refuel along the way.
Your car's sticker MPG and your real-world MPG are often very different. Highway driving, city stop-and-go traffic, air conditioning, tire pressure, and driving habits all affect your actual fuel economy. The Gaslo MPG calculator helps you measure the real number.
To use it: fill your tank completely, then reset your trip odometer to zero. Drive normally for a week or a full tank. When you refill, note the gallons it took and the miles on your trip counter. Enter both into Gaslo's MPG calculator and you'll see your true fuel economy — not the optimistic estimate on the window sticker.
Gas is one of the biggest variable expenses most drivers face, yet most people have no idea what they actually spend per month. The monthly gas budget calculator fixes that. Enter your average miles per day, your vehicle's MPG, and your local gas price — and Gaslo projects your full monthly fuel cost.
For example, if you drive 40 miles per day in a 28 MPG vehicle at $3.50/gallon, you're spending about $150 a month — or $1,800 a year — just on gas. Seeing that number clearly can motivate smarter driving habits, carpooling decisions, or even a vehicle upgrade.
One of the most common questions drivers have today is whether an electric vehicle would save them money. The answer depends entirely on your local electricity rate, your local gas price, your driving habits, and the specific vehicles you're comparing. Gaslo's EV vs Gas comparison calculator lets you run those numbers yourself.
Enter the number of miles you drive, your gas car's MPG, today's gas price, your EV's kWh per mile efficiency, and your home electricity rate (typically $0.12–$0.18/kWh in the US). Gaslo shows the total fuel cost for both options side by side, along with exactly how much you'd save — or spend — by going electric for that distance.
Calculating your fuel costs is the first step. Here are proven ways to actually reduce how much you spend at the pump every month.
Under-inflated tires increase rolling resistance, which forces your engine to work harder and burn more fuel. The U.S. Department of Energy estimates that keeping tires inflated to the correct pressure can improve gas mileage by up to 3%. Check your tires monthly — the correct pressure is listed on the sticker inside your driver's door, not on the tire sidewall. A digital tire pressure gauge costs under $15 and takes 30 seconds to use.
Rapid acceleration burns significantly more fuel than smooth, gradual acceleration. Studies show that aggressive driving (speeding, rapid acceleration, hard braking) can lower your gas mileage by 15–30% on highways and 10–40% in city driving. Use cruise control on the highway when possible, and anticipate stops so you can coast instead of braking hard.
Running out of gas is not just inconvenient — it can damage your fuel pump. A portable gas can stored in your trunk gives you a safety net for long drives or low-fuel emergencies. Use Gaslo's fill-up calculator every time so you never run low unexpectedly.
Dirty fuel injectors reduce fuel efficiency by spraying uneven fuel mist into your engine. Adding a fuel injector cleaner to your tank every 3,000 miles keeps injectors clean and can restore 1–4 MPG on older vehicles. It's one of the cheapest maintenance steps most drivers skip.
Before any long drive, make sure you have a car emergency kit with jumper cables, a flashlight, and basic tools. Breaking down on the highway without supplies is dangerous and expensive. Pair it with Gaslo's road trip calculator so you always know your fuel situation before you leave.
Many credit cards offer 3–5% cash back on gas purchases. If you spend $150/month on gas, a 5% cash back card saves you $90 a year with zero extra effort. Popular options include the Citi Custom Cash Card, the Blue Cash Preferred from American Express, and the Costco Anywhere Visa.
* This page contains affiliate links. If you purchase through these links Gaslo earns a small commission at no extra cost to you.
Enter your tank size (in gallons), how much fuel is left — using miles to empty, your trip odometer, or your gauge — and the current gas price per gallon. Gaslo instantly calculates the exact dollar amount you need to fill up completely. No more guessing at the pump.
Divide your trip distance by your car's MPG to get gallons needed, then multiply by the gas price. For example: 350 miles ÷ 28 MPG = 12.5 gallons × $3.50 = $43.75. Gaslo's trip fuel cost calculator does all of this instantly — just enter distance, MPG, and gas price.
Fill your tank, reset your trip odometer, then drive normally. When you refill, divide the miles driven by the gallons used. Gaslo's MPG calculator handles this math for you — just enter miles driven and gallons used and you'll get your actual fuel economy instantly.
The average American drives about 1,200 miles per month. At 28 MPG and $3.50/gallon that's roughly $150/month. Use Gaslo's monthly gas budget calculator to get a personalized estimate based on your actual daily mileage, vehicle MPG, and local gas prices.
Gaslo displays the current national average gas price at the top of the page, updated weekly from the U.S. Energy Information Administration (EIA). As of early 2026, the national average is around $3.10–$3.50 per gallon for regular unleaded, though prices vary significantly by state. California typically has the highest prices, while Southern states like Texas and Mississippi tend to have the lowest.
Tank sizes vary widely by vehicle. Most compact cars (Honda Civic, Toyota Corolla) hold 12–13 gallons. Mid-size sedans and crossovers typically hold 14–17 gallons. Full-size trucks and SUVs can hold 20–36 gallons. You can find your exact tank size on the sticker inside your fuel door, in your owner's manual, or by selecting your vehicle in Gaslo's built-in vehicle picker which uses EPA data.
Most mechanics recommend filling up when your tank reaches the quarter-full mark rather than running it to near-empty. Running on a very low tank repeatedly can wear out your fuel pump faster, since the pump uses the fuel as a coolant. Filling at half or quarter tank also means smaller, more predictable transactions — which is exactly what Gaslo is designed to help with.
Yes — Gaslo is completely free. No account, no signup, no app to download. Open gaslo.one on any device and start calculating immediately. It works on phones, tablets, and desktops in all modern browsers.