The gap this page fills
Type my dog is not eating into a search engine and you get ten pages built on the same frame. They open by saying a missed meal is usually not an emergency. They give a threshold in hours — one day for an adult, half a day for a puppy, sometimes two days if the dog is drinking. They list causes: dental pain, nausea, gastrointestinal upset, kidney disease, liver disease, pancreatitis, medication, stress, a recent vaccine, a change of food. They suggest warming the food, adding broth, trying chicken and rice, hand feeding. They close with when to call the vet.
None of it is wrong, and almost none of it is measurable. The threshold is a number of hours, which is a proxy for something the pages never name. The cause list is a differential, which cannot be narrowed from a kitchen. The advice is a set of things to try, with no way to tell afterwards whether they worked, because nothing was counted either before or after.
The gap is the measurement. A dog that has eaten a third of a day's requirement and a dog that has eaten none are in different places, and every page on the first screen of results puts them in the same one, because both are "not eating". A dog fed mostly canned food loses most of its water intake the moment it stops eating, and no page mentions it, because they all treat drinking as a separate behaviour. This page fills exactly that: it turns a refusal into a quantity of calories and a quantity of water, so that the hours everyone quotes have something behind them.
What the pages that rank actually contain
We pulled the first ten results and counted the words that would matter if any of them were doing arithmetic. One returned nothing readable to a crawler, so the counts below cover the seven we could read in full.
| Page | What it gives you | kcal | Calorie | Calculator |
|---|---|---|---|---|
| petmd.com | Causes, home care, when to call the vet | 0 | 2 | 0 |
| dogster.com | Possible causes, what to do, vet-reviewed | 0 | 0 | 0 |
| webmd.com | Causes and solutions, symptom check | 0 | 0 | 0 |
| animastica.com | Causes, warning signs, not eating or drinking | 0 | 0 | 0 |
| lovetoknowpets.com | When to worry, what to do at home | 0 | 0 | 0 |
| velacare.app | Causes and when to worry, vet triage app | 0 | 1 | 0 |
| caninescape.com | Twelve causes, home fixes, 24-hour rule | 0 | 1 | 0 |
Across seven full articles answering why a dog is not eating, the unit kcal appears zero times. The word calorie appears four times in total, and not one of the four carries a number. No page contains a calculator of any kind. Six of the seven give an hour threshold; none of them says what the hours are a stand-in for.
We are not saying the cause lists are wrong. They are the right reading for plenty of dogs. We are saying that no page lets you find out whether your dog is the one that needed the list or the one that needed a bigger portion of chicken, and that the test is two subtractions nobody has built.
How much a dog is supposed to eat in a day
The veterinary reference starts from the resting energy requirement: what a healthy, fed animal burns at rest in a thermoneutral environment. The exponential form is 70 multiplied by body weight in kilograms raised to the power of 0.75, and it holds at any body weight. The linear form, 30 times the kilograms plus 70, is restricted to animals over 2 kg.
Daily requirement is a multiple of that resting figure: 1.8 for an intact adult, 1.6 for a neutered adult, 1.4 for an obesity-prone one, 3 for a puppy under four months and 2 for a puppy over four months. Puppies sit far higher than adults, which is the single most useful fact on this page. The reference is explicit that any of these is a starting point to be adjusted for the individual, not a prescription.
Read as a table of what disappears in a day of not eating, the shape of the problem appears:
| Weight | Neutered adult | Intact adult | Puppy under 4 months | Per kg, adult | Per kg, puppy | Water per day |
|---|---|---|---|---|---|---|
| 10 lb / 4.5 kg | 348 | 392 | 654 | 77 | 145 | 248 mL |
| 20 lb / 9.1 kg | 585 | 659 | 1,098 | 64 | 121 | 501 mL |
| 30 lb / 13.6 kg | 794 | 893 | 1,488 | 58 | 109 | 748 mL |
| 40 lb / 18.1 kg | 985 | 1,108 | 1,845 | 54 | 102 | 996 mL |
| 60 lb / 27.2 kg | 1,335 | 1,501 | 2,502 | 49 | 92 | 1,497 mL |
| 80 lb / 36.3 kg | 1,656 | 1,863 | 3,105 | 46 | 86 | 1,997 mL |
| 100 lb / 45.4 kg | 1,958 | 2,202 | 3,669 | 43 | 81 | 2,497 mL |
The last two columns are the ones no other page prints. A ten-pound dog burns 77 calories per kilogram of body weight in a day; a hundred-pound dog burns 43. A puppy under four months burns nearly twice what an adult of the same size burns. Water is the published 44 to 66 mL per kilogram, taken at the midpoint.
How long can a dog go without eating
The answer every page gives is a number of hours, and the number is doing work it was never designed to do. Hours are a proxy. What is actually running down is the day's energy requirement, and that requirement is not the same for every dog at the same hour.
Take the two ends of the table above. A five-kilogram puppy under four months burns about 140 calories per kilogram of body weight in a day. A twenty-seven-kilogram neutered adult burns about 49. After twelve hours without food the puppy has spent roughly 70 calories per kilogram of its own body; the adult has spent about 24. The puppy has burned through nearly three times as much of itself in half the time.
That is the entire reason the published guidance gives puppies a shorter clock than adults, and it is the reason a single hour threshold cannot be applied to both. The clock is the same. The cost per hour is not. This is also why the number that matters is the percentage of requirement delivered, not the number of hours elapsed — and it is the number this page prints first.
Two honest caveats. First, the energy requirement formulas are a starting point, and the reference says so; an individual dog can sit above or below them. Second, nothing here says how long any particular dog can safely fast. That depends on reserves, on age, on body condition and on whatever else is going on, and it is a veterinary judgement. What this page does is replace "it has been a day" with a quantity you can put next to that judgement.
My dog is not eating but drinking water
This is the combination most owners describe, and it is the one where the water arithmetic is least obvious. Drinking water is reassuring — the pages are right about that — but "drinking" and "taking in water" are not the same sentence, because a large part of a dog's water arrives inside the food.
The veterinary reference gives the moisture content directly: canned pet foods vary from 60 to 87 percent water, dry foods contain 3 to 11 percent, and semimoist foods 25 to 35 percent. As a result, dogs eating predominantly canned food generally drink less than dogs eating predominantly dry diets. Run that against a sixty-pound neutered adult needing about 1,497 mL of water a day. On dry food at a typical 3,500 kcal/kg, the day's ration is about 381 grams, which carries roughly 27 mL of water — the bowl covers the rest, and stopping eating changes almost nothing about the water picture. On canned food at a typical 1,100 kcal/kg, the day's ration is about 1,214 grams, which carries roughly 892 mL. That is close to 60 percent of the day's water, arriving through the bowl of food.
When that dog stops eating, the water does not stop being needed. It stops being delivered, and the water bowl has to more than double what it was supplying before anyone notices the dog is "drinking fine". A canned-fed dog that refuses food is on a water clock, not just a calorie clock — and no page on the first screen of results says so, because none of them looks inside the food.
The practical version: if your dog is on wet food and has stopped eating, treat water as the thing to measure. Our water intake page gives the expected total for a dog of this size, and the dehydration page turns the physical signs into millilitres, which is the unit the question is actually in.
My dog is not eating or drinking
Both stopped. This is a different case from the one above, and it is not a more severe version of it — it is a shorter clock on a different substance.
Calories can be borrowed from reserves for a while. Water cannot be borrowed from anything. The reference puts maintenance water at roughly 44 to 66 mL per kilogram of body weight in a thermoneutral environment, and it is blunt that dehydration is a serious problem across a long list of disorders. A dog that is taking in neither food nor water is losing to both clocks at once, and the water one runs out first.
It is also worth knowing what the dog has stopped taking. A dry-fed dog that refuses everything loses the 27 mL inside the food and whatever it would have drunk — so the loss is almost entirely at the bowl. A canned-fed dog loses the bowl side and the food side together, and the food side was the larger half. Both cases end in the same place; the canned-fed one arrives sooner.
If a dog is eating nothing and drinking nothing, this page is the wrong tool to be reading first. Measure what you can, then call. What to have ready: the weight, how long since the last real meal and the last drink, whether there has been vomiting or diarrhoea, and whether the dog is a puppy, a senior, or on any medication.
My dog is not eating but acting normal
Bright, alert, interested in everything except dinner. This is the branch where the arithmetic earns its keep, because it is also the branch where "he will eat when he is hungry" is most often wrong.
A dog that is bright and refusing food has usually eaten something. Count it. The treats field on the calculator exists for exactly this: a dog that turns down two meals and then takes a cup of kibble's worth of chicken and a dental chew has not fasted, and the percentage will say so. If the percentage comes back above about a third, the shortfall is real but small, and a day of it is genuinely survivable for an adult dog that is drinking.
If the percentage comes back near zero and the dog is bright, the useful move is not to wait for hunger. It is to find out which of the two things is happening: the dog cannot eat, or the dog will not eat. Offering the food by hand separates them faster than anything else — a dog with a sore tooth or a sore mouth often takes food from a hand and refuses it from a bowl on the floor. So does warming it, because most of what a dog reads as flavour is smell.
What does not work is escalating the menu. Chicken, then beef, then scrambled egg, then whatever is in the fridge is the standard progression, and it produces a dog that has learned that refusing dinner produces something better. It also destroys the measurement: if the dog eats a different thing every time, nothing can be counted, and the next day starts from zero knowledge again.
My dog is not eating his food but will eat treats
Owners report this as a contradiction. It is not one — it is a quantity, and the quantity is usually smaller than it feels.
Work it out rather than arguing about it. A medium dental chew runs past a hundred calories. Two of them plus a handful of training treats can easily reach a quarter of a small dog's daily requirement and an eighth of a large one's. Against a full requirement, that is a partial fast that looks like a full one from the doorway. Against a dog that has also eaten nothing else for a day, it is the difference between "needs watching" and "needs an appointment".
The second half of this is that treats are not a meal in any sense that matters here. They are usually dry, so they bring almost no water with them. They are usually high in fat relative to their size, which is the last thing a nauseated dog needs. And they are the reason this pattern persists: a dog that has learned refusing dinner produces chicken will keep refusing dinner.
Practical rule: for the next twenty-four hours, count everything, including the thing you would not normally call food. Then decide from the percentage, not from the memory of how eager he looked.
My dog is not eating and throwing up
Vomiting changes the arithmetic in one specific way: what goes in does not stay in, and what comes back up takes water with it that no bowl measurement will ever show.
That makes the intake figure unreliable in both directions. A dog that eats and then vomits has not eaten. A dog that drinks and then vomits has not drunk. So in this branch the useful numbers are not the calories taken in — they are the hours, the number of episodes, and whether anything at all is being kept down.
Repeated vomiting with nothing kept down, in a dog that is also not drinking, is not a monitoring situation. It is also the case where the water side runs out first and fastest, and where the loss is invisible because it never passed through a bowl. If this is where you are, use the dehydration page to put the physical signs into volume, and treat the answer as a reason to call rather than a target to rehydrate towards by mouth — a dog that is vomiting will not hold oral water anyway.
Once or twice, with the dog still interested in food and water and keeping some of it down, is a different picture. Offer small amounts often rather than a full meal, because a large volume is both more likely to come back and more to lose if it does.
When to stop measuring
There is a point where quantities stop being the right instrument, and it is worth naming rather than leaving you to guess.
Stop measuring and call a vet if: the dog is a puppy and has eaten nothing for twelve hours; any dog has eaten nothing for a day and is also drinking less; there is repeated vomiting or anything that looks like an attempt to vomit without producing anything; the dog is lethargic, hiding, panting at rest, or showing pale gums or a distended abdomen; there is diarrhoea as well, or blood anywhere; or the dog is on medication, diabetic, or has a known kidney, liver or pancreatic condition. Also stop if the dog is very old, very young, or was already underweight before this started — the reserves the arithmetic assumes are thinner in all three.
Keep measuring if: the dog is bright, is drinking normally, has no vomiting, and the percentage says the shortfall is partial rather than total. In that case weigh the dog at the same time each day and re-run the tool. The number to watch is the weight, not the appetite — and if the weight is moving down while the dog is eating more than the tool says it needs, that is the case covered on the constant hunger page, because it is the same question with the sign reversed.
Questions people ask
Is it dangerous if my dog skips one meal?
For a healthy adult dog that is drinking, a single missed meal is usually not an emergency, and every page on this question says so. The number that makes the sentence true is the one nobody prints: a sixty-pound adult has skipped about 1,335 calories, which is a day of requirement. A ten-pound dog skipping the same meal has skipped 348. Neither is dangerous on its own; both are worth counting, because the second skipped meal is the one that changes the picture, and there is no way to know it happened unless the first was measured.
Should I force-feed or syringe water into a dog that will not eat?
No. Syringe feeding a dog that is refusing food risks aspiration, it does not reliably stay down, and it removes your ability to tell whether the appetite is coming back. If a dog cannot or will not take food or water by mouth, that is a veterinary problem and there are proper ways to manage it. Offer, do not force.
Does adding chicken and rice actually help?
It helps as a smell, and it hurts as a measurement. Plain chicken and rice are more appealing than kibble to most dogs, so they often get a refused dog eating again, which is the point. What they do not do is give you a number: chicken breast, rice and kibble have very different energy densities, and a cup of one is not a cup of another. Feed it if it works, then weigh the portion and use the kcal/kg figure for what you actually gave, so the next day starts from a real number.
How much water should a dog that is not eating be drinking?
More than usual, not less, if the food was wet. The published maintenance figure is roughly 44 to 66 mL per kilogram of body weight in a thermoneutral environment, and a dog on canned food was already getting most of that inside the food. When eating stops, the bowl has to cover all of it. The water intake calculator gives the expected total for a dog of this size.
Why does my dog refuse food but eat grass?
Grass eating is common and is not well explained by any single mechanism, so this page is not going to offer one. What matters for the question at hand is that grass is not food in any quantity that counts here — it contributes effectively nothing to the calorie or water arithmetic. If the dog is eating grass and vomiting, the vomiting is the finding, not the grass.
Can stress or a change in the house really stop a dog eating?
Yes, and it is the most common benign cause on every list. A move, a new baby, a houseguest, a lost companion, boarding, or a change in who feeds the dog can all do it. The test is the same arithmetic, though: a stressed dog that is still drinking and has taken in a third of a day's requirement is a very different case from one that has taken in nothing and is also not drinking. The cause list matters less than the quantity.
Is this page the same as the regular calorie calculator?
No. The dog calorie calculator answers how much to feed a dog that is eating. This page answers how much a dog is missing when it is not, and it adds the water that arrives inside the food. Use the calculator to set a portion; use this page when the portion is being refused and you need to know how much that refusal costs.
Sources
- Resting energy requirement: RER = 70 × (body weight in kg)0.75, usable at any body weight; the linear form 30 × kg + 70 is restricted to animals over 2 kg. Maintenance energy requirement multiples for dogs: 1.8 × RER intact adult, 1.6 × RER neutered adult, 1.4 × RER obesity prone, 2 × RER puppies over 4 months, 3 × RER puppies under 4 months; formulas described as a starting point to be modified based on how the patient responds. MSD Veterinary Manual — Nutritional Requirements of Small Animals
- Water: in a thermoneutral environment most mammalian species need approximately 44–66 mL/kg body weight; moisture content of canned pet foods varies from 60% to 87%, dry pet foods contain 3%–11% water, semimoist foods 25%–35%; dogs eating predominantly canned food generally drink less than those on dry diets; healthy animals self-regulate intake and water should not be restricted; dehydration is a serious problem in many disorders. MSD Veterinary Manual — Nutritional Requirements of Small Animals (Water)
- Daily maintenance energy requirement table for dogs and cats. MSD Veterinary Manual — Daily Maintenance Energy Requirements
- Maintenance fluid planning in animals, including ongoing and insensitive losses. MSD Veterinary Manual — Maintenance Fluid Plan in Animals
- Calorie content labelling on pet food, including the metabolizable energy statement and the calorie content per familiar unit. AAFCO — Calories
An estimate, not a diagnosis. This page applies published energy and water requirements to figures you supply from a label and a clock; it cannot examine a dog, and it cannot tell you why a dog has stopped eating. The percentages are arithmetic, not triage: if the dog is a puppy, is not drinking, is vomiting repeatedly, or is getting lethargic, the answer is a veterinary appointment rather than a better number. Nothing you enter here leaves your device.