Kitten Weight Curve: Weigh Weekly, Read 3 Signals

One weigh-in a week, on the same scale, before the same meal, is enough to catch a kitten sliding backwards 10-14 days before it looks thin. Healthy kittens gain 10-15 g a day in the first 12 weeks, which is 70-105 g a week. Three numbers do the work: daily gain, 7-day gain, and the 14-day trend. Everything else is noise from a full belly or a full bladder.

Set up a scale that gives usable numbers

Use a kitchen scale with 1 g resolution, not a bathroom scale that jumps 200 g. Weigh at the same hour, before the first meal and after the litter box, and put a towel in a shallow box so the kitten stays in one place for 5 seconds. Write the grams down, never the rounded kilos. If the kitten will not sit still, weigh yourself holding the kitten and subtract your own weight once, then never use that method again.

Why 10-15 g a day is the number

A newborn weighs 90-110 g and gains 10-15 g a day in the first 2 weeks, doubling birth weight by day 7-10. The same 10-15 g a day carries through to about 12 weeks, so an 8-week kitten at 800 g reaches roughly 1.1-1.3 kg at 12 weeks. From 12 to 20 weeks the daily gain rises to 15-25 g, and from 5 to 8 months it slows to 5-10 g a day as the curve flattens toward adult weight.

The weekly table

Ranges below cover most domestic kittens; large breeds such as Maine Coons sit at the top or above, and small-framed cats at the bottom. Use the action column only after 2 consecutive weigh-ins, never after one bad morning.

Age (weeks)	Typical weight (g)	Gain per week (g)	Gain per day (g)	Action if below range
1	120-200	70-105	10-15	Warm, feed every 3-4 h, call vet
2	200-300	70-105	10-15	Check latch, weigh daily for 3 days
4	350-500	70-105	10-15	Deworm, recheck in 72 h
6	500-700	70-105	10-15	Count calories, add a 4th meal
8	700-900	70-105	10-15	Vet visit within 48 h
10	900-1100	70-105	10-15	Fecal test, check for fleas
12	1100-1400	105-175	15-25	Bloodwork if flat 14 days
16	1600-2000	105-175	15-25	Review diet and portion size
20	2000-2600	70-105	10-15	Weigh every 14 days instead

The 3-tier judgment

Tier 1, normal: 70 g or more gained in 7 days, or 10 g a day. Change nothing. Tier 2, watch: 35-69 g in 7 days, or a flat week in a kitten under 16 weeks. Reweigh in 72 hours, count actual food intake for 3 days, and confirm the deworming schedule. Tier 3, vet: any weight loss, under 35 g a week for 2 straight weeks, or a flat curve plus diarrhea, sneezing or lethargy. A kitten has 1-2 days of reserve, not 1-2 weeks, so tier 3 means a call within 24 hours, not a wait for the next scheduled visit.

Read the trend, not the single point

Compute 3 values every Sunday: the 7-day gain in grams, the same gain as a percentage of body weight, and a 4-week average. A 1.2 kg kitten gaining 60 g a week is up 5%, which is fine; a 2.6 kg kitten gaining 60 g is up 2.3%, which is slow. A single weigh-in 40 g lower is usually a meal or a bowel movement, so never change the diet on one reading. Two points make a line; four make a trend.

What the scale cannot tell you

Weight hides body condition. Score ribs, spine and waist every 2 weeks on a 1-9 scale, target 5: ribs felt with light pressure, a visible waist from above. A kitten gaining 15 g a day but with a hard, distended belly after meals may be carrying worms rather than muscle. A kitten that gains well but looks pot-bellied at 8 weeks needs a fecal test before a diet change.

Common stalls that are not emergencies

Three normal reasons a curve flattens for 7-10 days: a vaccine day (a 24-48 hour dip of 20-50 g), a switch from 4 meals to 3, and the week after deworming when appetite drops briefly. A kitten rehomed in the past 7 days often eats 20-30% less for 3-5 days, so weigh daily during that week instead of weekly. A stall that lasts 14 days, or any stall with a 100 g drop, is not normal. The full decision tree for a flat line is in when kitten weight stalls, and the chart-reading method is covered in reading a kitten weight chart.

Sex and breed move the curve 20-30%

Males pull ahead from about 12 weeks and finish 20-25% heavier than females of the same breed. A Maine Coon at 16 weeks may weigh 2.5-3.2 kg where a Siamese sits at 1.5-1.9 kg, and both are healthy. Check the expected adult range for the breed before reading a slow week as a problem; the adult-size ranges for common breeds are a 2-minute lookup.

Two kittens, two curves

Littermates are not a control group. Weigh each kitten separately and plot 2 lines, because a pair that shares a bowl hides a 100 g gap easily. A 10% difference between siblings is normal; a 25% gap that widens over 2 weeks is a reason to watch the smaller one eat alone for 3 days and then call the vet.

Five steps this Sunday

Weigh before breakfast and log the grams, not kilos.
Compute 7-day gain in grams and in percent.
Score ribs and waist on the 1-9 scale.
Compare with the table row for the kitten's age.
Repeat in 7 days at the same hour, same scale.

Size and breed shift every number here by 20-30%, so check the expected adult range with the breed size guide before you worry about a curve.

Frequently asked

How much should a kitten gain per week?

Expect 70-105 g a week, or 10-15 g a day, through about 12 weeks. From 12 to 20 weeks the pace rises to 15-25 g a day, then slows to 5-10 g a day from 5 months as the curve flattens.

Is one flat week on the scale a problem?

Usually not. A vaccine, a meal change or deworming can flatten the curve for 7-10 days. Reweigh in 72 hours, count intake for 3 days, and act only if the next reading is also flat or lower.

When does a kitten weight problem need a vet?

Any weight loss, under 35 g a week for 2 straight weeks, or a flat curve with diarrhea, sneezing or lethargy. Kittens have 1-2 days of reserve, so call within 24 hours rather than waiting for the next visit.