Why Gas Prices End in 9/10: What the “Extra 9” Really Means

It represents nine-tenths of a cent. When a sign shows, for example, $3.29 with a small “9/10,” the actual price is $3.299 per gallon (or per liter in some countries). This fractional-cent pricing dates back to early fuel taxes and Depression-era price wars, and it persists because it lets stations advertise a price that looks a hair cheaper while still being computed precisely at the pump and rounded to the nearest cent on your total.

What the extra 9 actually means at the pump

In the United States, the small “9/10” on a gasoline sign is 0.9 of a cent added to the dollars-and-cents price. So $3.29 9 reads as $3.299 per gallon. Pumps perform the math using that exact price and then round your total purchase to the nearest cent on the final charge.

How the math works

Here’s how the fractional cent is applied and how your total is calculated step by step.

1. Convert the posted price: $3.29 9 = $3.299 per gallon.
2. Multiply by the number of gallons pumped. Example: 12.5 gallons × $3.299 = $41.2375.
3. Round the total to the nearest cent: $41.24 is what appears on your receipt.

This process ensures you’re charged accurately for the fractional cent across the entire fill-up, with normal rounding to a whole cent at the end.

Why gas prices adopted the 9/10 convention

The practice emerged nearly a century ago and has stuck due to a blend of regulation, competition, and consumer psychology.

• Historical taxes and price wars: As fuel taxes and margins tightened in the 1920s–1930s, stations began using tenths of a cent to undercut rivals by the smallest possible increment.
• Psychological pricing: $3.29 9 looks closer to $3.29 than $3.30, anchoring perception to the lower whole-cent figure even though the true price is $3.299.
• Industry standardization: Once common, the 9/10 ending became an expected market signal, making even-cent pricing comparatively rarer.
• Legal and signage norms: Many jurisdictions explicitly allow fractional-cent pricing, and some (such as California) require stations to display the fraction clearly on signs and dispensers.

Together, these forces turned 9/10 from a temporary tactic into a durable industry convention that consumers now recognize instantly.

Is the “extra 9” a tax or a fee?

No. The 9/10 is part of the base price the station posts, which generally already includes applicable taxes. It isn’t a separate surcharge. If a station also has a cash/credit price difference or other fees, those must be posted separately; the 9/10 is independent of those policies.

How much does the 9/10 add up to?

The extra 0.9 of a cent matters only in aggregate. On a typical fill-up, it’s noticeable but modest.

• Compared with $3.29 even, $3.29 9 costs an extra $0.009 per gallon—about 9 cents on 10 gallons.
• Compared with $3.30 even, $3.29 9 is cheaper by $0.001 per gallon—about a tenth of a cent per gallon, or roughly 1 cent on 10 gallons.
• Over months of driving, the difference can add up to a few dollars, but it’s small relative to overall fuel costs and price volatility.

In everyday terms, the 9/10 is a subtle but real component of price competition, not a hidden windfall.

Legality, signage, and receipts

Fractional-cent pricing is legal in the U.S. and widely used in Canada, the U.K., and Australia (where prices are commonly posted to a tenth of the smallest currency unit). Weights-and-measures rules require pumps to compute accurately and receipts to show the correct rounded total. Many states also regulate how the fraction is displayed so consumers can see it clearly.

Common myths vs. facts

These points clarify frequent misconceptions about the extra 9.

• Myth: The station “keeps” the fraction beyond a cent. Fact: Your total is calculated precisely and rounded normally; there’s no unaccounted remainder.
• Myth: 9/10 is a special tax. Fact: It’s part of the posted price; taxes are embedded or itemized separately depending on local rules.
• Myth: The 9/10 is required by federal law. Fact: Federal law permits fractional pricing; specific display requirements come from state and local regulations.
• Myth: It’s unique to the U.S. Fact: Similar tenths-of-a-unit pricing appears in Canada (cents per liter), the U.K. (pence per liter), and Australia (cents per liter).

Understanding these distinctions helps decode the sign without overestimating the fraction’s impact on your bill.

Will the 9/10 ever disappear?

Some retailers occasionally experiment with even-cent pricing, but the competitive signaling and psychological effects of 9/10 make it likely to persist. As long as stations compete at very fine price increments and consumers react to leftmost digits, the convention has staying power.

Bottom line for drivers

The “extra 9” means you’re paying $X.XXX per gallon (or per liter), not just $X.XX. Your pump charges the precise amount, and your receipt rounds to the nearest cent. It’s a longstanding, legal marketing convention rather than a separate fee—and it changes your total by pennies per fill-up.

Summary

The extra 9 on gas prices is nine-tenths of a cent, making a posted price like $3.29 9 equal to $3.299 per gallon. The practice dates to early fuel taxes and price wars and endures due to competitive and psychological pricing effects. Pumps compute it exactly, your total is rounded to the nearest cent, and it’s part of the posted price—not an added fee.

What is the extra 9 on gas prices?

Gas stations passed on the tax straight to the consumer by tacking it on to the price of fuel that day. The tax wasn’t always nine-tenths of a penny. Sometimes it was a smaller fraction. But by the 1950s, gas stations started rounding up to the 9/10 pricing, “squeezing the buck as far as they can,” Jacobsen told CNN.

What does the small 9 mean in gas prices?

Over time, fuel retailers evolved to pricing at 0.9 cents. The reason is marketing. Retail experts have long known that goods prices slightly less than those priced at a whole number sound far less expensive. Something that is priced at $9.99 seems a lot less expensive than something priced at $10.

How to read gas prices in the US?

To read gas prices in the US, look for the large price signs at a gas station, which show the cost per gallon, usually ending in 9/10ths of a cent. The total cost is displayed in dollars and cents, corresponding to the gallons you pump. Factors like crude oil costs, refinery and distribution expenses, taxes, and supply and demand all influence the final price.
 
Understanding the Price at the Pump

1. 1. Cost Per Gallon: Opens in new tabThe listed price is the cost for one gallon of fuel, including all taxes, distribution, refining, and the cost of crude oil. 
2. 2. The 9/10ths of a Cent: Opens in new tabThe practice of ending gas prices with 9/10ths of a cent began in the 1930s due to price competition and the ability of fuel dispensers to measure precisely. It remains a standard practice today as a marketing strategy to make the price seem lower. 
3. 3. Fuel Types: Opens in new tabPrices are listed for different fuel types, such as regular, premium, and diesel. 

Key Factors Influencing Gas Prices

• Crude Oil Costs: Opens in new tabThe price of crude oil is the largest factor in the price of gasoline. 
• Supply and Demand: Opens in new tabLike any commodity, gasoline prices fluctuate based on the overall supply and consumer demand. 
• Refining and Distribution: Opens in new tabCosts for refining crude oil into gasoline and transporting it to stations also affect the final price. 
• Taxes: Opens in new tabBoth federal and state governments add taxes to the price of a gallon of gas. 
• Geopolitical Events: Opens in new tabGlobal events, such as wars or sanctions, can significantly impact oil supplies and thus gasoline prices. 

How to Find the Best Price 

• Use Apps: Mobile apps like GasBuddy and Waze can help you find the cheapest gas stations near you.
• Check for Discounts: Some stores, such as Kroger, Costco, or Sam’s Club, offer gas discounts to their members.
• Consider Cash vs. Credit: In some cases, paying with cash can result in a lower per-gallon price at certain stations.

What does the 9 mean on gas?

“Level 9 gas” can mean a couple of different things, but most likely refers to a 99.999% pure gas grade used in technical or industrial applications, where the numbers indicate the purity by the number of nines. It could also be a reference to the slang term “gas” meaning something is “excellent” or “cool,” though “level 9” is not a standard slang grading for it. 
Here are the most common interpretations:

• Gas Purity (Technical): Opens in new tabIn scientific and industrial contexts, “level 9” often refers to a 99.999% pure gas. This is sometimes called “five nines” purity. The “level” or “grade” is based on the number of nines in the purity percentage, with higher numbers indicating greater purity. 
• Slang for “Excellent” or “Cool”: Opens in new tabThe word “gas” is slang for something excellent, awesome, or cool. While “level 9” is not a standard part of this slang, someone might use it to emphasize how exceptionally good something is. 

Therefore, without additional context, it’s difficult to say for sure, but in most technical or industrial settings, “level 9 gas” implies a very high level of purity, whereas in casual conversation, it may simply be a slang term.