The Bristol Stool Chart: all 7 types, explained
Seven types, one scale, and a surprisingly good window into how your digestive system is working. Here is how to read it — and what your type is actually telling you.
On this page
What the Bristol Stool Chart actually is
The Bristol Stool Chart — sometimes called the Bristol Stool Scale or Bristol Stool Form Scale — is a seven-point scale that classifies human stool by shape and consistency. It was developed by Dr Ken Heaton and Dr Stephen Lewis at the University of Bristol and published in 1997.
It was not invented to be a health quiz. It was built as a research instrument, because researchers needed an objective way to measure transit time: how long it takes food to travel through your digestive system. That turns out to be the single most useful thing the chart tells you.
The logic is simple. Your colon's main job is absorbing water. The longer stool sits there, the more water gets pulled out and the harder it becomes. The faster it moves through, the more water stays in and the looser it is. So the shape of your stool is essentially a clock.
All 7 types at a glance
| Type | What it looks like | What it suggests |
|---|---|---|
| Type 1 | Separate hard lumps, like nuts. Hard to pass. | Constipation — longest time in the colon |
| Type 2 | Sausage-shaped but lumpy. | Mild constipation |
| Type 3 | Sausage-shaped with cracks on the surface. | Healthy |
| Type 4 | Smooth, soft, sausage or snake-like. | Healthy — often called ideal |
| Type 5 | Soft blobs with clear-cut edges. | Trending fast; may be normal for you |
| Type 6 | Fluffy, mushy pieces with ragged edges. | Mild diarrhoea |
| Type 7 | Entirely liquid, no solid pieces. | Diarrhoea — fastest transit |
Types 1 and 2: things are moving too slowly
Type 1 is separate hard lumps that are genuinely difficult to pass. Type 2 is lumpy and sausage-shaped — the individual lumps have compacted together but you can still see them.
Both mean stool has been sitting in the colon long enough for a lot of water to be reabsorbed. Straining, a feeling that you have not finished, and going less often than usual tend to travel with them.
The usual culprits are unremarkable: not enough fibre, not enough fluid, not enough movement, a disrupted routine from travel, or a new medication. Iron supplements and some painkillers are common offenders. Our guide on what actually relieves constipation covers what the evidence supports.
Types 3 and 4: the healthy middle
This is where you want to live. Type 3 is sausage-shaped with surface cracks; type 4 is smooth and soft, like a snake. Both hold together, both pass easily, and neither requires straining.
The straining test. If you are unsure where you sit, forget the picture for a second and ask a simpler question: did it come out easily, and did you feel finished afterwards? Comfort and completeness are better everyday signals than trying to match a photo exactly.
Types 5, 6 and 7: things are moving too fast
Type 5 is soft blobs with clear edges. For plenty of people this is simply their normal, particularly if they eat a lot of fibre. It is worth noticing mainly as a direction of travel.
Types 6 and 7 are mushy and liquid respectively, and both count as diarrhoea. Short bouts are extremely common — an infection, a reaction to something you ate, stress, alcohol, or a new medication will all do it.
What matters is duration. A day or two is usually nothing. Diarrhoea that runs for more than a couple of days, or that keeps returning, is worth a conversation with a doctor — partly because of what it might indicate, and partly because of dehydration.
How to use the chart properly
The single biggest mistake is treating one stool as a verdict. It is not. The chart is only useful as a pattern over time.
- Log the type, not the drama. One number per visit is enough.
- Give it two to four weeks. Anything shorter is noise.
- Note what changed. A new medication, a trip, a stressful fortnight, a diet change — the context is what makes the pattern readable.
- Watch the direction. Drifting from 4 to 2 over a month is far more informative than any single entry.
- Bring it to appointments. “Mostly type 6 for three weeks, starting when I began this medication” is a genuinely useful sentence. “My stomach has been off” is not.
You can do all of this with a notebook. The reason an app helps is that it removes the friction at the moment you would otherwise not bother, and it does the pattern-spotting for you afterwards.
When to see a doctor
See a doctor promptly if you notice any of these
- Blood in your stool — bright red, or black and tar-like.
- Unexplained weight loss alongside a change in your bowels.
- A persistent change in habit lasting more than a few weeks.
- Persistent pain, vomiting, or a fever with the change.
- Pale stools with yellow skin or eyes and dark urine.
- A family history of bowel cancer or IBD, or you are over 45 and something has changed.
None of these mean something is seriously wrong — most have ordinary explanations. They are simply the ones worth getting looked at rather than watched.
Track it, don’t guess it
Dookie Deluxe logs type, colour, symptoms and timing in seconds — then turns weeks of entries into a pattern you (and your doctor) can actually read.
Common questions
What is the healthiest type of poop?
Types 3 and 4. Both are soft, formed, and pass without straining. Type 4 — smooth and sausage-shaped — is usually described as the ideal, but type 3 is just as healthy.
Is type 5 poop bad?
Not necessarily. Type 5 is soft blobs with clear edges, and for some people that is simply normal. It becomes worth paying attention to if it is new for you, or if it is drifting towards types 6 and 7.
What does type 1 poop mean?
Separate hard lumps, like nuts, that are difficult to pass. Type 1 has spent the longest in the colon, which has drawn out the most water. It is the classic sign of constipation.
Can my stool type change day to day?
Yes, and it should. A single unusual stool after a big meal, a late night or a course of antibiotics tells you almost nothing. What matters is your pattern over weeks, which is exactly why tracking beats remembering.
Who invented the Bristol Stool Chart?
It was developed by Dr Ken Heaton and Dr Stephen Lewis at the University of Bristol and published in 1997. It was designed as a research tool for measuring how fast food moves through the gut, and it is now used in clinics worldwide.