Litter Weights in Week 1: 10-15 g a Day, +15% by Day 7

Week 1 has 3 numbers worth memorizing: a newborn kitten weighs 90 to 120 g, a healthy kitten gains 10 to 15 g a day, and by day 7 the litter floor is 15 percent above birth weight. Weigh once a day at the same hour on a 1 g scale, write the number down, and compare it with the day before rather than with the littermates.

This page covers grams and weighing frequency only. It is a record-keeping protocol for a litter that is already on the ground, not a guide to mating, pregnancy, or birth, and nothing here replaces an exam when a kitten stops gaining.

The 3 numbers for week 1

Birth weight first. A kitten under 90 g at birth starts behind and needs a weight check twice a day for the first 3 days. A kitten at 120 g or more has a buffer measured in days rather than hours, which is why birth weight is recorded before anything else on the sheet.

Daily gain second. Ten to 15 g a day is the working range for the first 7 days, and it roughly doubles birth weight by day 7 to 10 in a well-fed litter. A gain of 8 g a day is not a crisis on day 1 and is a pattern by day 4. Gain third: the percentage. Ten grams on a 90 g kitten is 11 percent; 10 g on a 130 g kitten is 8 percent. Percent is what lets you compare a small kitten with a large one without arguing about size.

Weigh once a day, same hour

One weighing per 24 hours, at the same clock time, before the first feed of the day. Same scale, same towel, zeroed each time. A towel that weighs 40 g one day and 55 g the next silently adds 15 g to the reading, which is a full day of growth. Write the towel weight on the sheet once and check it every 7 days.

A 1 g kitchen scale is enough for a litter above 90 g at birth. Below that, use a 0.1 g scale, because 1 g is already more than 1 percent of the kitten. Put the scale on a hard floor or a stone counter, never on carpet, and weigh with the kitten in the same small basket every time. The whole set of 5 kittens takes 4 minutes once the basket is on the counter.

Do not weigh more than twice a day in week 1. Hourly weights bounce with feeding and urination by 5 to 10 g, and the noise hides the trend you are trying to see. Twice a day is for a kitten under 90 g at birth or one that lost weight on the previous check.

The 3-column sheet

Column 1: date and clock time. Column 2: weight in grams, to the nearest gram. Column 3: gain against birth weight in percent, filled in at the end of each day. Three columns, 7 rows, one page per litter, with the litter letter and the queen's name on the header (naming rule), and the page stays on the wall next to the scale. A phone note works too, but a paper sheet survives a wet hand at 3 a.m.

Add 1 optional field: the smallest kitten's weight, circled. In a litter of 5, the smallest kitten is the one that decides whether the week went well, and circling it means you never have to search 7 rows to find it.

2 abnormal curves

Curve 1 is loss. Any kitten below its birth weight on day 2, or down 10 percent or more at any check, is abnormal. A 100 g kitten at 89 g on day 2 is a 11 percent loss and a same-day call. A kitten below birth weight on day 3 is a call regardless of how active it looks.

Day	Target weight (g)	Gain vs birth (%)	Flag below (g)
0	100	0	90
1	110 to 115	10 to 15	100
2	120 to 130	20 to 30	100
3	130 to 145	30 to 45	105
5	150 to 175	50 to 75	110
7	170 to 205	70 to 105	115

The flag column is the day-7 floor of 15 percent spread backward, so a kitten at 112 g on day 7 is above the floor and still well below the track. Both facts go in the same sentence when you call: 112 g on day 7, up 12 percent, gaining 2 g a day for 3 days.

Curve 2 is flat. The same weight plus or minus 2 g for 2 consecutive days, while littermates gain 10 to 15 g a day, is the earliest reliable signal in the whole week. Flat is easier to miss than loss, because the kitten is not going backwards, and it is the curve that most often turns into a 3-day problem before anyone calls.

Litter totals, and why the average lies

Weigh the litter as a group only as a cross-check. A litter of 5 that gains 50 g in total looks healthy, but that total can hide 1 kitten at plus 18 g and another at minus 8 g. The group number is a 30-second sanity check; the individual number is the record.

Track the spread too. In week 1, the gap between the heaviest and the lightest kitten commonly runs 30 to 60 g, and a gap that widens by 15 g or more across 3 days is worth a call even when every kitten is gaining. A shrinking gap is the sign that the small one has caught up.

What the scale cannot tell you

A weight is a trend, not a diagnosis. The scale will not tell you why a kitten is flat, and it will not tell you whether the cause is temperature, feeding, infection, or something congenital. It tells you when to ask, and the answer to when is: 2 flat days, 1 loss of 10 percent, or any kitten below 90 g at birth. Call with the sheet in hand and read the last 3 numbers.

Take the litter to the vet with the sheet rather than a summary. Seven rows of grams let a vet see a 4-day trend in 20 seconds, and a trend is what separates a kitten that needs help today from one that needs a check on Friday.

Week 1, in 5 steps

Day 0: weigh every kitten within 2 hours, record birth weight, towel weight, and scale model.
Day 1: set the daily weighing at the same hour, before the first feed, and circle the smallest kitten.
Day 2: check for any kitten below birth weight, and call if 1 exists.
Day 4: compare each kitten's 4-day gain; a gain under 8 g a day for 2 days is a call.
Day 7: confirm every kitten is at or above 115 percent of birth weight, then photograph the page.

Keep the 7 pages. A second litter, or the same queen 12 months later, is compared against these numbers, and 1 page of grams beats every memory of how the last litter went.

Frequently asked

How often should newborn kittens be weighed in the first week?

Once a day at the same hour, before the first feed, on a 1 g scale. Weigh twice a day only for a kitten under 90 g at birth or one that lost weight on the previous check. More frequent weighing adds noise, because a full belly or a full bladder moves the number by 5 to 10 g. Record grams and the percent gain over birth weight, then compare each kitten with its own yesterday.

What weight gain is normal for a kitten in week 1?

Ten to 15 g a day is the working range, which puts a 100 g kitten near 170 to 205 g by day 7. The floor is 15 percent above birth weight, so 115 g for that kitten. A gain of 8 g a day is acceptable on day 1 and a pattern by day 4. Any kitten below birth weight on day 3, or down 10 percent at any check, needs a call rather than another day of watching.

The litter total looks fine but one kitten is small. What now?

Trust the individual number, not the total. A litter of 5 can gain 50 g overall while one kitten loses 8 g, so keep a per-kitten column and circle the smallest. If the gap between heaviest and lightest widens by 15 g or more across 3 days, call with the sheet and read the last 3 weights. The group total is a 30-second cross-check, never the record.