Guides

What is actually in there

Almost none of it is the part you notice. Roughly 99% of the volume is nitrogen, hydrogen, carbon dioxide, oxygen and — in about a third of people, the ones whose gut bacteria happen to include the right microbes — methane. All five are odourless. The smell comes from the remaining fraction of a percent, and it is almost entirely the work of three sulphur compounds.

The gas itself arrives by two routes, and they explain most of the differences between one person and the next:

• Swallowed air, which is mostly nitrogen and oxygen. Eating fast, talking while you eat, chewing gum and fizzy drinks all push this up. It adds volume and almost no smell.
• Fermentation in the colon, where bacteria break down the carbohydrates your small intestine could not absorb. This is where hydrogen, carbon dioxide, methane and the sulphur compounds come from — so it drives both the volume and the odour.

That split is why the foods that make you gassy and the foods that make you unbearable are not the same list. Beans produce volume; cabbage, eggs and red meat feed the sulphur.

Why your own count always sounds too low

Most people guess three or four a day and are genuinely surprised by the real figure. In 1991 a team at the Royal Hallamshire Hospital measured it directly rather than asking, and found healthy volunteers averaging around 700 mL a day spread over roughly 5 to 25 passages.

The gap between the guess and the measurement has a dull explanation: you sleep through a good share of them, and you stop registering the ones that happen while you are walking, driving or otherwise occupied. The count that feels abnormal to you is usually the ordinary one, finally being paid attention to.

Where to start

Depending on what brought you here:

• Worried the number is too high → how many a day is normal, which has the actual range and what sits outside it.
• Worried about the smell rather than the frequency → why they smell.
• Trying to work out what you ate → foods that cause gas, sorted by mechanism rather than by how often they get blamed.
• Here to settle an argument → myths and facts. One of the twelve claims turns out to be true, which is usually the surprise.

When it stops being a game

Frequency on its own is a poor warning sign — the range is wide and it moves with what you eat. What matters is a change that sticks around, especially alongside weight loss, blood, persistent pain, or diarrhoea or constipation that will not settle. Those are worth a doctor rather than a leaderboard.

This is general information, not medical advice. FartRank is a game. If your symptoms are painful, sudden, persistent, or come with weight loss, bleeding or a change in bowel habits, talk to a doctor — not to a leaderboard.

How the game itself works

The scoring is documented in full on how scoring works — the formula, the context multiplier table, the daily limits and the rules that keep the leaderboard reasonably honest.

Sources

• Tomlin J, Lowis C, Read NW. Investigation of normal flatus production in healthy volunteers. Gut, 1991.
• Suarez FL, Springfield J, Levitt MD. Identification of gases responsible for the odour of human flatus. Gut, 1998.
• NHS — Flatulence
• Cleveland Clinic — Gas and gas pains

Published 26 August 2026 · by Furiosa Studio