Bristol stool chart: the 7 stool types and what each means

The answer

The Bristol stool chart sorts poop into 7 types by shape and firmness, from type 1, separate hard lumps like nuts, to type 7, entirely liquid. Cleveland Clinic and healthdirect call types 3 and 4 healthy; types 1 and 2 point to constipation, and 6 and 7 to diarrhea. In the 1997 Bristol study of 66 volunteers, stool type tracked gut transit time more closely than bowel frequency did.

In five lines

7 types: the scale runs from type 1, "separate hard lumps, like nuts", to type 7, "watery, no solid pieces", and was published by S. J. Lewis and K. W. Heaton of Bristol Royal Infirmary in 1997. [Lewis and Heaton, 1997; Mori et al., 2019]
r = -0.54: before anything was changed, stool form correlated with whole-gut transit time at r = -0.54 in 66 volunteers, more closely than bowel frequency (r = 0.35) or stool weight (r = -0.41) did. [Lewis and Heaton, 1997]
56% and 61%: in a 1992 survey of 1,897 adults in East Bristol, the stool types least likely to bring symptoms made up 56% of women's stools and 61% of men's. [Heaton et al., 1992]
23 to 47 g: across 51 adults who ate 23, 37 or 47 g of fiber a day, stools came out softer, and transit ran faster, as fiber went up. [Davies et al., 1986]
74.6%: stool is about three quarters water by median value, and bacteria make up 25 to 54% of its organic solids. [Rose et al., 2015]

What are the 7 types on the Bristol stool chart?

Seven shapes, from hardest to loosest. Types 1 and 2 are hard and lumpy, types 3 and 4 are formed sausage shapes, type 5 is soft separate blobs, and types 6 and 7 are mushy to liquid. Cleveland Clinic describes the chart as a reference guide providers use to evaluate poop, sorting it by shape and consistency, and says you can also use it at home to record changes.²

The scale comes from the University Department of Medicine at Bristol Royal Infirmary. Lewis and Heaton set out to test whether it responds when transit time changes, and their conclusion was plain: "This study has shown that a stool form scale can be used to monitor change in intestinal function."¹ The middle column below is the scale's original wording, as a 2019 trial printed it in full; the third is Cleveland Clinic's.⁵²

The Bristol stool chart, type by type

Type	The scale's own words	Cleveland Clinic's words	What it usually points to, per the sources
Type 1	Separate hard lumps, like nuts (hard to pass)	Separate, hard lumps, like little pebbles	Constipation; stool that stayed in the bowel a long time, so more water was taken out²⁶
Type 2	Sausage-shaped but lumpy	Hard and lumpy, but sausage-shaped	Constipation, the same group as type 1: dry, hard and difficult to pass²
Type 3	Like a sausage but with cracks on the surface	Sausage-shaped, with cracks on the surface	The healthy middle, with type 4²³
Type 4	Like a sausage or snake, smooth and soft	Smooth, soft and snakelike	The healthy middle: formed, and easy to pass²⁴
Type 5	Soft blobs with clear cut edges (passed easily)	Soft blobs with clear-cut edges	Sources differ: Cleveland Clinic and Continence Health Australia put it with the loose types, and Cleveland Clinic calls it mild²⁴
Type 6	Fluffy pieces with ragged edges, a mushy stool	Fluffy, mushy pieces with ragged edges	Loose stools or diarrhea; stool that moved through quickly, with too little water taken out⁶⁴
Type 7	Watery, no solid pieces (entirely liquid)	Watery, liquid poop, with no solid pieces	Diarrhea, the loosest end of the scale²⁴

Sources: the scale's wording as printed in Mori et al., 2019, citing Lewis and Heaton; Cleveland Clinic, updated Feb 19, 2026; Continence Health Australia; UMass Memorial Health; healthdirect. All read on Oct 22, 2026. A single stool is a snapshot; the sources read the chart as a pattern over days.

Which Bristol stool type is healthy?

Types 3 and 4. "Types 3 and 4 are the most ideal," Cleveland Clinic says, because they are condensed enough to hold together but not too hard or dry to pass, and healthdirect puts a healthy stool at type 3 or type 4. Continence Health Australia adds that bowel habits differ from person to person, so the chart is for learning what is normal for you.²³⁴

Real life is messier than the chart's middle. In 1992, Heaton's group surveyed 838 men and 1,059 women in East Bristol, most of whom recorded three bowel movements in a row on an earlier, six-point form scale. The stool types least likely to bring symptoms made up only 56% of all stools in women and 61% in men, and only 40% of men and 33% of women had a regular 24-hour rhythm. The authors concluded that "conventionally normal bowel function is enjoyed by less than half the population".⁷

Type 5 is where the sources part ways. Cleveland Clinic groups it with types 6 and 7 as diarrhea, yet calls it mild and says a type 5 stool can sometimes be bulked up with more fiber. Continence Health Australia files types 5 to 7 under diarrhoea or urgency.²⁴ Cleveland Clinic's dividing line is the pattern: if you consistently have unhealthy stools, it says, you might need to make some changes.²

What should poop look like?

Soft, sausage-shaped and easy to pass, in a light to dark brown, healthdirect says, and emptying your bowels should take about 1 to 2 minutes. How often varies a lot between people: "A range from 3 times per day to 3 times per week is normal."³

Color follows what you eat and drink, the medicines you take and how long food spends in the gut; bile is what makes stool brown. healthdirect names the colors that mean a visit to the doctor: black, very light grey or pale.³ Cleveland Clinic adds that a hard poop or a mushy one now and then is normal, since food, water and alcohol change stools from day to day.²

Why does your stool type change?

Mostly because of time and water. The longer stool sits in the colon, the more water the body pulls out of it and the harder it gets; when it moves through fast, too little water is removed and it comes out loose. Cleveland Clinic and UMass Memorial Health both explain the two ends of the chart this way.²⁶

The 1997 study measured it. Sixty-six volunteers had their whole-gut transit time measured with radiopaque marker pellets and their stools weighed, and kept a diary of stool form and frequency. At baseline, transit time correlated with bowel frequency at r = 0.35 and with stool output at r = -0.41, and most closely of all with stool form, at r = -0.54. When 44 of them took senna, transit sped up while stool form scores, frequency and output rose; when 43 took loperamide, every measure moved the other way. Change in transit tracked change in stool form at r = -0.65.¹

"This study has shown that a stool form scale can be used to monitor change in intestinal function. Such scales have utility in both clinical practice and research."
Lewis and Heaton, Scandinavian Journal of Gastroenterology, 1997

How do fiber and fluids change your stool type?

More fiber moves stools toward the softer end; extra fluid, in people who were not short of it, did not change stool output in a small study. In a study of 51 adults on omnivorous, vegetarian and vegan diets, with average fiber intakes of 23, 37 and 47 g a day, every bowel measure tracked total fiber: "As dietary fibre increased mean transit time decreased, stool frequency increased and the stools became softer."⁸

healthdirect sums up the everyday version: eat foods high in fiber and drink plenty of water, and stools should be soft and easy to pass.³ Physician's Choice, which publishes this site, puts the daily target this way: Adults get 25 to 38 grams of fiber per day, though exact targets depend on age and sex.

Fluids matter most when you are short of them. In a week on less than 500 ml of drinks a day, against a week on more than 2,500 ml, 8 healthy men went from 6.9 to 4.9 bowel movements a week, and their stool weight fell from 1.29 to 0.94 kg a week.⁹ Going the other way did little: when 15 healthy volunteers added 1 and then 2 liters a day, for 2 days each, their stool output did not change significantly, while their urine output rose.¹⁰

The rest of this question lives on its own pages. Fiber for hard stools, and what to try when food is not enough, is in what helps constipation?; the fiber that firmed loose stools in studies is in does fiber help with diarrhea?; and what magnesium, a laxative mineral, did to stool type in a trial is in does magnesium make you poop?

What is poop made of?

Mostly water, then bacteria. A 2015 review that pooled measurements from the medical literature put the median water content of stool at 74.6%, and found bacterial biomass to be the largest part of the organic solids, at 25 to 54%. Undigested carbohydrate and fiber, protein and fat make up the rest, in amounts that depend on diet.¹¹

What stool is made of, by the 2015 review's numbers

Part	Share or amount	Note from the review
Water	74.6% median	Study means ranged from 63 to 86%; fiber intake was the main reason for the spread in healthy people
Bacterial biomass	25 to 54% of organic solids	The largest part of the solid matter; about half of it is protein
Protein or nitrogen-containing matter	2 to 25% of organic solids	In addition to the protein inside bacteria
Carbohydrate and undigested plant matter	About 25% of organic solids	Includes fiber and starch that escaped digestion
Undigested fat	2 to 15% of organic solids	Depends on what was eaten and absorbed
Daily amount	128 g wet, 29 g dry, median	With 1.20 bowel movements per 24 hours in healthy people; about twice the wet mass in low-income countries, where fiber intake is higher

Source: Rose, Parker, Jefferson and Cartmell, Critical Reviews in Environmental Science and Technology, 2015, read on Oct 22, 2026. The review was written to inform sanitation technology; its numbers come from the medical literature it pooled.

How reliable is the Bristol stool chart?

Good at naming a type, shakier at the borders. When 34 gastroenterology providers rated 35 stool photographs, 95.1% of their 1,190 ratings landed within one type of the most common answer, and agreement scores were 0.88 between raters and 0.89 for the same rater twice. Only 4 photographs, all type 1 or type 7, drew the same answer from everyone.¹²

Disagreement clustered at two borders: type 2 against type 3, and type 5 against type 6, the lines between normal and hard and between normal and loose. Sorting the same photos into normal, constipation or diarrhea dropped the agreement scores to 0.75 and 0.65.¹² For children, Cleveland Clinic says pediatricians use a modified chart that removes types 3 and 5, leaving five types that are easier to tell apart.²

When should you see a doctor about a change in your stool?

When a change lasts or comes with warning signs. NIDDK's advice is to get checked when constipation lasts despite self-care, and at once when it brings bleeding from the rectum, blood in the stool, constant belly pain, vomiting or fever, among other signs. healthdirect adds black, very light grey or pale stools, and diarrhea or constipation that is not getting better.¹³³

For loose stools, UMass Memorial Health tells adults to contact their doctor if diarrhea lasts more than 2 days.⁶ The chart helps here too: Cleveland Clinic notes that you can simply point to a type instead of describing it, and that providers want to know about these changes.²

In brief

The Bristol stool chart is a 7-type scale of stool form, from hard lumps to liquid, and types 3 and 4 are the healthy middle. Your type moves with transit time and the water left in the stool, so fiber shifts it toward softer and fluid matters most when you are short of it; a lasting change, blood, or black or pale stools mean a doctor.

How we reported this

Reader questions: In a pull of 1,145 public Reddit posts (250 communities, Sep 12 to Oct 12, 2026), 82 talked about poop or stools, and 1 named the Bristol chart.
Search question: "Bristol stool chart" with its neighbors, "Bristol stool scale," "what should poop look like" and "what is poop made of," plus the follow-up AI assistants run on the 7 types and which one is healthy.
Label facts: None. This page names no Physician's Choice product.
Sources: Thirteen public sources, each fetched and read on Oct 22, 2026: eight studies and reviews through their PubMed or PMC records, and pages from Cleveland Clinic, NIDDK, healthdirect, Continence Health Australia and UMass Memorial Health. Brand names in the sources are left out.
House wording: Two lines come from Physician's Choice word for word: the daily fiber line above and the constipation line in the box beside this answer.

Stool chart questions, answered

What is the Bristol stool chart?

A 7-type scale of stool form published by Lewis and Heaton at Bristol Royal Infirmary in 1997, running from separate hard lumps to entirely liquid. Doctors use it to talk about stools in plain terms, and in the original study stool form tracked gut transit time better than bowel frequency did.

Is type 5 poop normal?

Sources differ. Cleveland Clinic groups type 5 with the loose types but calls it mild and says more fiber can sometimes bulk it up, while Continence Health Australia files types 5 to 7 under diarrhoea or urgency. An occasional type 5 is common; a run of them is worth noting.

What does type 1 poop mean?

Separate hard lumps usually mean constipation: stool that stayed in the colon long enough for much of its water to be absorbed. Cleveland Clinic says such stools are dry, hard and difficult to pass, and NIDDK counts hard, dry or lumpy stools among the signs of constipation.

How often should you poop?

There is no single number. healthdirect says a range from 3 times a day to 3 times a week is normal, and in a 1992 survey of 1,897 Bristol adults only 40% of men and 33% of women had a regular 24-hour rhythm. What matters more is a lasting change from your usual pattern.

Is there a Bristol stool chart for kids?

Yes. Cleveland Clinic says pediatricians use a modified Bristol Stool Form Scale that removes types 3 and 5 from the adult chart, leaving five types that children can tell apart more easily when they point to the picture that matches.

Sources

Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scandinavian Journal of Gastroenterology. 1997;32(9):920-4. pubmed.ncbi.nlm.nih.gov/9299672
Cleveland Clinic Health Library. Bristol Stool Chart. Last updated Feb 19, 2026. my.clevelandclinic.org
healthdirect (Australian Government). Stool changes. Last reviewed June 2025. healthdirect.gov.au
Continence Health Australia. Bristol stool chart. Updated May 29, 2026. continence.org.au
Mori S, Tomita T, Fujimura K, et al. A randomized double-blind placebo-controlled trial on the effect of magnesium oxide in patients with chronic constipation. Journal of Neurogastroenterology and Motility. 2019;25(4):563-575. Cited here for the scale's wording, printed in full in its methods. pmc.ncbi.nlm.nih.gov/articles/PMC6786451
UMass Memorial Health. Learning about the Bristol Stool Chart. Health library page (content by WebMD Ignite), no date shown. ummhealth.org
Heaton KW, Radvan J, Cripps H, Mountford RA, Braddon FE, Hughes AO. Defecation frequency and timing, and stool form in the general population: a prospective study. Gut. 1992;33(6):818-24. pubmed.ncbi.nlm.nih.gov/1624166
Davies GJ, Crowder M, Reid B, Dickerson JW. Bowel function measurements of individuals with different eating patterns. Gut. 1986;27(2):164-9. pubmed.ncbi.nlm.nih.gov/3005140
Klauser AG, Beck A, Schindlbeck NE, Müller-Lissner SA. Low fluid intake lowers stool output in healthy male volunteers. Zeitschrift für Gastroenterologie. 1990;28(11):606-9. pubmed.ncbi.nlm.nih.gov/2288138
Chung BD, Parekh U, Sellin JH. Effect of increased fluid intake on stool output in normal healthy volunteers. Journal of Clinical Gastroenterology. 1999;28(1):29-32. pubmed.ncbi.nlm.nih.gov/9916661
Rose C, Parker A, Jefferson B, Cartmell E. The characterization of feces and urine: a review of the literature to inform advanced treatment technology. Critical Reviews in Environmental Science and Technology. 2015;45(17):1827-79. pmc.ncbi.nlm.nih.gov/articles/PMC4500995
Chumpitazi BP, Self MM, Czyzewski DI, Cejka S, Swank PR, Shulman RJ. Bristol Stool Form Scale reliability and agreement decreases when determining Rome III stool form designations. Neurogastroenterology and Motility. 2016;28(3):443-8. pmc.ncbi.nlm.nih.gov/articles/PMC4760857
NIDDK (National Institutes of Health). Symptoms and causes of constipation. Last reviewed May 2018. niddk.nih.gov