Knowing when to euthanize a dog comes from three things read together: the signs vets watch for, a week-by-week score of how those signs are changing, and your vet's examination. No single sign decides it. The pattern across several weeks, brought to the vet, is what most families and most vets act on.
The signs vets watch
Veterinary hospice uses a seven-part list because it covers the things that actually change at the end. It asks whether the pain is still controlled and the breathing easy, whether he eats and drinks on his own, whether he can stay clean, whether he still responds to the people and things he loved, whether he can get up, and, across the whole week, whether the good days still outnumber the bad.
Each of those is scored from one to ten on the dog quality of life scale, which you can fill in on this site in a few minutes. The total matters less than the direction. One low week is a bad week. Three falling weeks in a row is a decline, and a decline is what the vet needs to see.
What families describe most often in the last weeks, whatever the illness, is some version of this: he stopped eating on his own, then he stopped getting up on his own, then he stopped coming to find them. If two of those have happened, the question you are asking is the right one to be asking.
What euthanasia involves
Most people searching this have never been through it and want to know what the room will be like before they are in it. That is sensible. Your vet will walk you through it in more detail, but the shape of it is this.
The vet gives a sedative first, by injection. Over a few minutes your dog gets heavy and calm and stops noticing where he is. Then a second injection, usually into a vein in the front leg, sometimes through a small catheter placed earlier. The heart stops within a minute or so. The vet listens, and tells you. Vets describe it as one of the most peaceful deaths they see.
Afterwards the body may breathe out, or twitch, or release the bladder. The vet will warn you. It is the body and not the dog, and it is still a shock. You can stay in the room as long as you need. You can hold him the whole time. Vets often say dogs look for their person at the end and are calmer when the person is there.
Many practices will come to the house, and there are services that do only this. Ask. The questions about what happens to his body afterwards, cremation and ashes and the rest, the vet will raise with you before the day, so that you are not deciding it in the room.
What the vet knows that you don't
You know this dog. The vet knows this illness. Go in with the scored weeks and ask what the next month probably holds, what would count as a crisis for this condition, and whether anything left to try would give him good days rather than just more of them. Ask whether the pain is being controlled or only masked. Those are answerable questions, and a good vet will answer them plainly.
If you want their honest view, ask what they would do if he were theirs. Most will tell you, gently. That is not the same as being told what to do, and it isn't a vet making the decision for you. It's one more honest voice in a room that usually has too few.
What to do the week before
If there is time, use it for him and not for the arrangements. The vet will handle the arrangements. Feed him the thing he was never allowed. Sit in the yard. Take the photo of your hand on his head, because that is the one many people say they keep looking at. Keep the day quiet; a tired dog is made more tired by a parade of visitors.
Too early, too late
The fear of going too early is loud. The regret of going too late is quieter, and families describe it more often. Very few people say afterwards that they wish they had waited longer. Many say they wish they had been braver a week sooner.
If you are reading this with a dog who still has good days, that is not a reason to wait for them to run out. Many families choose a day while there is still something good left in it, so the last day can be one of the good ones.
If you're still deciding
There is a longer piece on this site, with less of the clinical detail and more of the sitting-with, on how to know when to put your dog down. It doesn't try to decide for you either. Read whichever one meets you where you are.
And when it is done, there are poems written for the day a dog passes, one of them for exactly the people who had to make this choice. Some families also want a place for his name and photo that isn't a phone. If that is you, later, a memorial page is here.
Questions people sometimes ask
What signs do vets watch for before euthanizing a dog?
Vets watch seven things: uncontrolled pain or laboured breathing, not eating, not drinking, not being able to stay clean, withdrawing from the household, not being able to get up, and more bad days than good. No one sign decides it. Several at once, over weeks, is what families and vets act on.
What happens during euthanasia?
A sedative first, so your dog relaxes and stops noticing the room. Then a second injection, usually into a vein in the leg, and the heart stops within a minute or so. The vet confirms it. You can stay the whole time, and most vets encourage it.
Does the dog feel anything?
Vets describe it as falling asleep. The sedative does its work first. The body may move or breathe out afterwards, which is a reflex and not the dog, and the vet will tell you to expect it.
Can it be done at home?
In most areas, yes. Many practices do home visits and there are services that do only this. Ask your vet. It costs more, and for many families the familiar floor is worth it.
How much does it cost?
It varies a great deal by region, whether it's at home or in the clinic, and whether cremation is included. Ask your vet for the figure plainly. They're used to the question.