Kitten Weekly Weight Log: 50 to 100 Grams a Week

Weigh a growing kitten once a week on the same weekday, at the same hour, on a scale that reads to 5 grams, and write the number down. Between 8 and 20 weeks a healthy kitten adds 50 to 100 grams a week. A flat line for 2 weeks, or a drop of more than 5 percent from the highest weight on the sheet, is the point to book a vet visit instead of waiting for the next month.

A fixed weekly slot beats daily weighing

After 8 weeks, daily weighing produces noise more than information. A kitten's weight moves 20 to 40 grams across a single day depending on when it last ate, drank, or used the litter box. One reading a week, same weekday, same hour, before the first meal, lets a 50 to 100 gram weekly trend show through the daily swing. The exception is a kitten under 8 weeks or under 500 grams: weigh that one daily, because at 500 grams a 10 gram change is 2 percent of body weight and 2 flat days in a row is an event.

Set up a scale that reads 5 grams

A digital kitchen scale with 1 gram resolution costs less than a bag of treats and holds 5 gram accuracy once a wriggling kitten is on the platform. Put a shallow cardboard box on it, tare to zero, and set the kitten in with all 4 feet down. Read the display 3 times over 10 seconds and keep the middle value, because a moving kitten can swing the number by 15 to 25 grams. For cats over 4 kg a baby scale with a 10 gram step is enough, since 10 grams is 0.25 percent of a 4 kg cat. Record grams only, keep the same decimals, and never mix pounds into the sheet.

What 50 to 100 grams a week looks like by age

Growth starts fast and flattens near 6 months. At 8 weeks a typical kitten weighs 700 to 900 grams and gains about 100 grams a week. At 12 weeks it sits at 1.1 to 1.4 kg with a 100 to 120 gram weekly gain. At 16 weeks the gain eases to 80 to 100 grams, and at 20 weeks to 50 to 80 grams. Large breeds such as Maine Coons and Norwegian Forest Cats run 20 to 30 percent above those figures at the same age, so an adult size estimate keeps you from chasing the wrong target; the breed size quiz returns a range in about 2 minutes.

Three abnormal lines that force a decision

A log without rules is a diary. Three lines turn it into a decision tool. Line 1 is 2 consecutive weeks under 50 grams of gain. Line 2 is any single week that is flat or negative. Line 3 is a drop of 5 percent or more from the highest weight already recorded. Cross 1 line and reweigh in 48 hours at the same hour; cross 2 lines, or stay across the same line for 2 weeks, and book a visit within 7 days. Write the 3 lines at the top of the sheet so anyone in the house applies the same rule.

Weekly targets by age

Age	Typical weight	Weekly gain	Action if the gain is missed
8 weeks	700 to 900 g	80 to 100 g	reweigh in 48 hours
12 weeks	1.1 to 1.4 kg	100 to 120 g	count food intake for 3 days
16 weeks	1.6 to 2.0 kg	80 to 100 g	vet visit within 7 days
20 weeks	2.0 to 2.6 kg	50 to 80 g	fecal test plus recheck
6 months	2.6 to 3.5 kg	30 to 50 g	move to monthly weighing

Six fields per entry, 40 seconds of work

Each row needs date, hour, weight in grams, food eaten in the previous 24 hours in grams, litter box output (normal, soft, or none), and a 1 to 5 body condition note. Six fields take about 40 seconds and separate a growth problem from a measurement problem. A kitten that ate 15 grams less the day before reads 15 to 20 grams light. One with soft stool for 2 days can read 30 grams light from water loss alone. Without those fields you cannot tell which line you just crossed.

Read the slope, not the single number

One weight is a point; 4 points make a line. Plot every weekly number and compare the slope with the 50 to 100 gram band for the age. A curve that is smooth but low is usually a small kitten from a small litter. A curve that bends down once and recovers is usually a feeding or illness blip. A curve that bends down and stays down is the pattern that needs bloodwork. The guide to reading a weight chart explains the percentile bands, and the weight stall protocol walks through the first 48 hours of a flat line in order of what to check.

When the sheet says see a vet

Call within 24 hours for any of these: no gain for 7 days in a kitten under 12 weeks, a 5 percent drop plus vomiting or diarrhea, weight loss with a swollen belly, or a gain under 30 grams a week at 16 weeks. Bring the sheet to the appointment. A vet who can see 8 weekly numbers in 10 seconds orders fewer tests than one starting from a single weight in a 15 minute slot, and you leave with a plan instead of a guess.

Five steps for this week

Buy or borrow a scale with 1 gram resolution and check it with a 100 gram calibration weight.
Fix the slot: same weekday, 06:00 to 08:00, before food, clothes off the scale, box tared.
Write the 3 abnormal lines on the sheet: under 50 grams twice, any flat week, a 5 percent drop.
Fill all 6 fields for 4 weeks before judging the trend; 4 points is the minimum for a slope.
Set a phone reminder for the weekly weigh and a second one 48 hours after any missed line.

Frequently asked

My kitten gained only 40 grams this week. Should I worry?

Check the age first. Between 8 and 20 weeks the floor is 50 grams a week, so 40 grams is one crossed line, not an emergency. Reweigh in 48 hours at the same hour, before food, and look at the food eaten in those 2 days. If the next number is also under 50 grams, or lower than today, book a visit within 7 days and bring the whole sheet.

Is a 5 gram scale accurate enough for a kitten?

Yes for a kitten over 8 weeks that already weighs 700 grams or more, where 5 grams is under 1 percent of body weight. Under 8 weeks, or under 500 grams, use 1 gram resolution and weigh daily, because a 10 gram change there is 2 percent of the kitten and 2 flat days in a row is a real event rather than noise.

When in the day should I weigh the kitten?

Same hour every week, in the morning between 06:00 and 08:00, after the litter box and before the first meal. A kitten weighed 30 minutes after eating reads 20 to 30 grams heavy, and a full bladder adds another 10 to 20 grams. Fixing the hour removes most of that error without any equipment beyond the scale.