Nobody loves talking about poop, but its shape and colour are two of the simplest health signals your body gives you every day. The Bristol Stool Chart is the standard scale doctors use to describe stool form. Our free checker below walks you through it: pick the type that looks most like yours, its usual colour, and how long it has been that way, and you will get a plain-English read on what it likely means, and the warning signs that should always go to a doctor, not a website.
Bristol Stool Checker
Answer three quick questions about your stool and get a plain-English read on what it likely means, plus the warning signs that always need a doctor.
Tap the closest colour.
This checker is educational only. It cannot diagnose anything, and it is not a substitute for medical advice. If anything about your stool worries you, see a doctor. That is always the right call.
What Is the Bristol Stool Chart?
The chart was developed at the Bristol Royal Infirmary in England and published in 1997 by researchers Stephen Lewis and Ken Heaton. It sorts stool into seven types, from the hardest and slowest (Type 1) to the fastest and most watery (Type 7). Doctors use it because form is a rough guide to how long food took to travel through your gut, the longer the journey, the more water is absorbed, and the harder the stool.
| Type | What it looks like | What it usually means |
|---|---|---|
| Type 1 | Separate hard lumps, like nuts | Constipation, very slow transit |
| Type 2 | Sausage-shaped but lumpy | Mild constipation |
| Type 3 | A sausage with cracks on the surface | Normal |
| Type 4 | Smooth, soft sausage or snake | Normal, the ideal |
| Type 5 | Soft blobs with clear-cut edges | Borderline, often not enough fibre |
| Type 6 | Fluffy, mushy pieces with ragged edges | Mild diarrhoea |
| Type 7 | Entirely liquid, no solid pieces | Diarrhoea, fast transit |
Stool Colours, Briefly
Colour matters alongside form. Brown, in any shade, is normal. Green usually just means food moved through quickly, or that you ate a lot of leafy greens. Yellow and orange are often diet or medicines. Three colours are different, and they are the reason the checker asks: black (which can be digested blood, though iron tablets and bismuth medicines also cause it), red (which can be blood, though beetroot can fool you), and pale or clay-coloured (which can mean bile is not reaching the gut). Any of those three, unexplained and persistent, should be checked by a doctor.
On Keto? Why Your Stool Changes
If you eat low-carb, a shift towards Type 1 or 2 in the first weeks is extremely common, and it is usually fixable. Keto removes most of the fibre sources people rely on (grains, beans, fruit), the body sheds water early on, and magnesium and other minerals can run low, all three firm stool up. The fixes that work for most people: build fibre back up gradually from keto-friendly sources (chia, flax, avocado, leafy greens, raspberries), hit your water target using our water intake calculator, and check your minerals with our keto electrolyte calculator. Magnesium in particular is the constipation mineral nobody talks about. Increase fibre slowly: a big jump all at once causes gas and bloating, and fibre without enough water can make constipation worse, not better.
When to See a Doctor, Do Not Skip This
See a doctor promptly if you notice blood in your stool or on the paper, black tarry stool, pale or clay-coloured stool, severe or ongoing stomach pain, fever, diarrhoea lasting more than two days, vomiting or signs of dehydration, or weight loss you cannot explain. And whatever the checker says: any change from your normal that lasts more than about two weeks deserves a medical opinion. Bowel changes can be early signs of conditions that are very treatable when caught early, this is not a corner to cut.
This checker is an educational tool based on the Bristol Stool Form Scale. It does not and cannot diagnose any condition, and it is not a substitute for medical advice.
Bristol Stool Chart FAQs
What is the healthiest stool type?
Type 4, a smooth, soft sausage, is generally considered ideal: formed enough to hold together, soft enough to pass without straining. Types 3 and 4 are both in the normal range for most people.
How often should you poop?
There is no single right number. Anything from three times a day to three times a week can be normal, as long as it is your usual pattern, it is comfortable, and it has not suddenly changed. A lasting change in frequency matters more than the number itself.
Can stress change your stool?
Yes. The gut and brain are closely linked, and stress and anxiety commonly speed the gut up (looser stool, urgency) or, for some people, slow it down. If a stressful period explains a short-lived change, it usually settles as things calm down.
When is constipation actually a problem?
If you are straining most of the time, passing hard lumps (Types 1–2) for more than a couple of weeks despite more fibre and water, or constipation is new and unexplained, especially over the age of 50, get it checked rather than just treating it forever at home.