How often does a healthy person pass gas? You would think someone would know. A fart is gas from inside your belly that comes out of your bottom, and experts consider passing it up to 25 times a day to be normal. But ask a few sources and you get different answers. Burping and passing gas are natural and common, and they are normal parts of how a body works.

Here is the spread, as of November 2026. Counts of daily gas passing differ by source. Studies suggest an average of 8 to 14 times a day, and one hospital says 13 to 21. Another source says most people make about 1 to 4 pints of gas a day and pass gas about 14 times a day. A third count says most people pass gas up to about 20 times a day, so the sources overlap but do not match.

There is great variability in how much and how often people pass gas, so a normal day for one person is different from a normal day for another. On average people pass about 600 to 700 milliliters of gas a day, which sits inside the usual range of half a liter to one and a half liters. Not all gas is passed at all. A lot of it is absorbed into the blood or burped up before it ever leaves through the bottom.

Gas in the digestive tract has two main sources: air that is swallowed, and gas made when bacteria in the large intestine break down food. A gas has no fixed shape or size, and in a closed container it spreads out to fill all the space. The gas in your digestive tract is air mixed with other gases. Swallowed air is mostly nitrogen and oxygen, while gas made by bacteria from food is mostly carbon dioxide, hydrogen and sometimes methane.

About three quarters of fart gas (74 percent) is hydrogen, methane and carbon dioxide made by bacteria in the large intestine as they ferment food. The smell comes from a much smaller share. About 1 percent of a fart is made of the gases that cause the odor, and the common gases in it, like nitrogen and carbon dioxide, have no smell.

Burps get counted too. People typically belch up to 30 times a day, as of November 2026, and belching during or after meals is normal. Burps are more likely soon after a meal. Many people feel a tight, full feeling in the chest or stomach just before a burp, and that feeling goes away once the gas is out. Most swallowed air comes back up as burps, and very little of it goes on to the rest of the digestive system.

What makes people swallow extra air? Drinking through a straw is one of the everyday ways to swallow extra air. So are chewing gum, sucking on hard candy and talking with your mouth full. People also swallow extra air when they eat or drink too fast. Carbonated drinks and beer are made fizzy with carbon dioxide gas, and the gas is released inside you and can come back up as burps.

Farting happens when bacteria in the large intestine work on parts of your food that your own body cannot digest. It is a normal process, and the gas has to go somewhere, so it leaves as a toot. Holding a fart in does not make it disappear. The gas just builds up inside, which can make your belly feel full or puffy until it finds its way out, one way or another.

Some foods make more gas than others. Beans make more gas partly because of the sugars inside them. Beans and other legumes are full of sugars people cannot digest, and soy flour made with less of those sugars produces less gas than ordinary soy. Gassy foods are not only beans. Fruits such as apples, pears and prunes, and vegetables such as broccoli, onions, carrots and cucumbers, are all foods linked to extra gas.

Not all gut gas leaves through the bottom. Gut bacteria make carbon dioxide when they ferment food. Most of it is soaked up through the wall of the colon into the blood and then breathed out, so some gut gas leaves through your lungs instead of your bottom.

Can a fart spread germs? A fart is not a way to spread germs. A gastroenterologist says there is no evidence you can spread germs through flatulence, unless poop is present. And if you wonder who studies all of this, a scientist who studies flatulence is called a flatologist.

Words to know

• belch: a burp
• flatulence: passing gas
• flatologist: gas scientist
• variability: how much differs
• legumes: beans and peas
• gastroenterologist: gut doctor