Bottle feeding fails on arithmetic more often than on technique. Three numbers decide whether a kitten gains weight: the powder-to-water ratio, the energy that ratio produces, and the daily volume its body weight allows. Get those right and the rest is warmth, posture, and patience.
The ratio is 1:2 by volume
Mix 1 part powder to 2 parts water, which means 1 scoop to 2 scoops, or roughly 10 g powder to 20 ml water depending on the brand. The result runs about 20 to 25 kcal per 100 ml, close to queen's milk at 22 to 24 kcal per 100 ml. Follow the tin, because scoop sizes differ between brands. A 1:1 mix is the most common and most expensive error, and it produces diarrhea and dehydration in a kitten with no reserves.
Mix with water at 45 to 50C so the powder dissolves, then cool to feeding temperature. Made formula keeps 24 hours in the fridge and 2 hours at room temperature, and whatever is left in the bottle after a feed goes down the sink. Bacteria multiply fast, and a 3-week-old has nothing to spend on a gut infection.
Daily volume: 15 to 20 ml per 100 g
The working rule is 15 to 20 ml of made formula per 100 g of body weight per day, split across 6 to 8 feeds. A 200 g kitten takes 30 to 40 ml a day, or 4 to 6 ml per feed over 7 feeds. Newborns under 1 week need 8 to 10 feeds including overnight; by 3 weeks, 6 feeds; by 4 weeks, 5 to 6 as weaning starts.
Weigh daily at the same time, before the first feed, on a scale with 1 g resolution. Trust the weight, not the appetite: a kitten that drains every bottle but gains 5 g a day is underfed.
| Body weight | Daily formula | Per feed, 7 feeds |
|---|---|---|
| 100 g | 15-20 ml | 2-3 ml |
| 150 g | 22-30 ml | 3-4 ml |
| 200 g | 30-40 ml | 4-6 ml |
| 250 g | 37-50 ml | 5-7 ml |
| 300 g | 45-60 ml | 6-9 ml |
38C, wrist-tested, never microwaved
Feed at 38C (100.4F). Drop a little on your inner wrist: it should feel neither warm nor cool. A microwave creates hot spots that burn the mouth even when the bottle feels right, so stand the bottle in a cup of hot water for 2 to 3 minutes and swirl. Do not shake hard. Shaking whips air into the milk, and that air is what comes back up.
Posture, pace, and the burp
Feed belly down with the head level or slightly up, never on the back like a human baby. A kitten on its back aspirates, and aspiration pneumonia moves fast. Let it suck at its own pace, hold the bottle at 45 degrees so the nipple stays full, and finish a feed in 5 to 10 minutes. A kitten that empties the bottle in 60 seconds is getting too much too fast, and a nipple that drips when inverted has too large a hole.
Burp after every feed: sit the kitten upright, support the chest, and rub the back in slow circles for 30 to 60 seconds until you hear or feel the release.
Stimulation first, then the box
Kittens under 3 weeks cannot urinate or defecate unaided. Before and after each feed, stroke the genitals and anus with warm damp cotton for 10 to 15 seconds. Expect urine at every feed and stool once or twice a day. No stool in 48 hours is a vet call, not a reason to stimulate harder.
At 3.5 to 4 weeks the pan appears: 2 to 3 cm of non-clumping litter in a shallow tray, 30 cm from the sleeping spot, with the kitten placed in it after every feed. Most get it within 3 to 5 days, and the earlier the tray shows up the fewer puddles you mop. Keep it at least 1 m from food and water, because no kitten toilets next to its dinner, and if the tray gets used as a bed or not at all, the placement rules in litter box training fix most of it.
Weight gain and the weaning curve
Target 10 to 15 g of gain per day, about 100 g a week, from birth to 4 weeks, with birth weight doubled by day 7 to 10. At 4 weeks offer gruel, 1 part kitten canned food to 3 parts formula, and drop one bottle every 3 to 4 days. By 6 to 8 weeks the kitten should be eating solid food and lapping water. Size the portions with the food calculator rather than by eye: a weaning kitten needs roughly 2 to 2.5 times adult calories per kilogram, so a 500 g kitten at 6 weeks may take 60 to 70 kcal a day split over 4 meals.
When the kitten starts mouthing hands
Between 5 and 7 weeks a bottle kitten discovers that fingers are warm, mobile, and attached to the person who brings food. That mouthing is the start of play biting, and it gets reinforced every time a hand pulls away fast or pushes back. Swap in a soft toy at the first contact, break off the cuddle for 30 seconds, and let a littermate do the teaching when there is one. A single orphan has nobody to yelp, which is why the habit sticks so hard in hand-raised kittens.
A kitten that latches onto a hand during burping is not being dominant. It is 6 weeks old and teething on the nearest warm object. Never flick the nose or hold the mouth shut; both raise arousal and make the next bite harder.
Red flags
Call a vet the same day for diarrhea lasting over 12 hours, no gain for 48 hours, a bloated belly after a feed, milk coming from the nose, a body cool to the touch, or a kitten too weak to suck. Hypoglycemia moves from sleepy to seizing in hours. Never add sugar, honey, or cow's milk: cow's milk causes diarrhea, and honey carries a botulism risk in the first year.
Five steps for the next feed
- Weigh the kitten and write the number down.
- Calculate 15 to 20 ml per 100 g, then divide by 6 to 8 feeds.
- Mix 1:2 with 45 to 50C water and cool to 38C.
- Feed belly down, 5 to 10 minutes, then burp for 30 to 60 seconds.
- Stimulate elimination, and log the weight again tomorrow.
Frequently asked
Can I mix a whole day of formula at once?
You can make 24 hours at a time if it goes straight into the fridge and stays below 4C, but no longer. Anything warmed and fed must be discarded after 2 hours at room temperature, and leftover milk in the bottle goes down the sink. For a 100 g kitten taking 15 to 20 ml a day, single-feed mixing is easier and safer.
My kitten finishes every bottle but is not gaining weight. Why?
Either the mix is too dilute or the daily total is too low. Check that you are using 1 part powder to 2 parts water and that the volume is 15 to 20 ml per 100 g of body weight, not per kitten. A kitten gaining under 10 g a day for 48 hours needs a vet visit to rule out parasites, diarrhea, or an infection.
When can I stop stimulating the kitten to poop?
Usually between 3 and 4 weeks, once it starts using a shallow tray on its own. Keep stimulating after feeds until you see it produce stool in the litter, then stop. If stools stay soft or the kitten strains, keep the tray closer and check with a vet rather than adding cereal or changing the ratio.