How to Weigh a Cat at Home

Quick answer Weigh a cat on a baby scale, or a kitchen scale with a tared box or carrier, or hold the cat and subtract your own weight. A 100 g error is 2.5% of a 4 kg cat, so use a scale that reads to 10 to 50 g, the same method each time, and judge trends over several weeks.

Cats hide weight changes well. A fluffy coat covers a gain, and a loss of 400 g in a 4 kg cat, a tenth of its weight, can go unnoticed for weeks. Yet weight is one of the best early signs of a problem, in either direction, and the cat’s small size makes errors large. A bathroom scale that reads to 100 g can hide a change that matters. This guide describes four ways to weigh a cat at home, how accurate each is, how to get a cat to cooperate and how to log the numbers so that trends show. It builds on our guide to weighing a dog at home and the arithmetic in how to track your pet’s weight change.

Why accuracy matters more for cats

The same error is a bigger share of a small cat.

Cat weight	10 g error	50 g error	100 g error	200 g error
3 kg	0.3%	1.7%	3.3%	6.7%
4 kg	0.2%	1.2%	2.5%	5.0%
5 kg	0.2%	1.0%	2.0%	4.0%
6 kg	0.2%	0.8%	1.7%	3.3%

A change of 5% in a month is a good threshold for a call to the vet: 200 g for a 4 kg cat. With a scale that reads to 100 g, the reading could be 100 g out in either direction, enough to hide half of that change or to invent half of it. A scale that reads to 10 to 50 g is much better.

Method 1: baby scale

A baby scale is built for small weights and reads to 5 or 10 g. Many have a curved tray that holds a squirming infant, which suits a cat too.

Place the scale on a flat, stable surface and zero it, with a towel on the tray if you use one.
Lift the cat on, with a hand near but not pressing.
Wait until the reading settles, and note it.
Repeat twice and take the average.

If the scale has a hold function, use it, since cats move. This is the most accurate home method for most cats, provided the cat fits and stays on.

Method 2: kitchen scale with a box

A kitchen scale reading to 1 to 5 g and a capacity of at least 5 to 10 kg works with a box or a carrier on top.

Put the empty box on the scale and press tare (zero).
Place the cat in the box, which may have a lid with air holes if the cat is nervous.
Read the weight, which is the cat alone.

A box with a non-slip mat and a familiar blanket helps the cat settle. Check that the scale’s maximum is above the combined weight of the box and cat. Cardboard boxes crush and affect readings; use a rigid one.

Method 3: carrier on a bathroom scale

If you have a carrier, weigh it empty and with the cat, and subtract. Cats are often comfortable in their own carrier.

Step	Example
Weight of carrier and cat	7.6 kg
Weight of empty carrier	3.4 kg
Cat alone	4.2 kg

The result carries the rounding error of two readings. On a scale that reads to 0.1 kg, each reading could be 0.05 kg out, so the result could be about 0.1 kg out, 2.4% of the cat’s weight, which is too coarse for tracking small changes. Use a scale with a finer reading if you can.

Method 4: hold and subtract

Weigh yourself, then weigh yourself holding the cat, and subtract.

Step	Example
You and the cat	64.3 kg
You alone	60.1 kg
Cat	4.2 kg

Use the same clothes, take both readings in a row and hold the cat securely, since a fall can injure you both. As with the carrier method, the error is that of two readings, so it suits only scales that read to 0.1 kg or finer, and you should treat the result as approximate. Many cats dislike being held, and a frightened cat may scratch.

Choosing a method

Method	Typical reading	Best for	Watch for
Baby scale	5 to 10 g	Most cats	The cat fitting and staying
Kitchen scale with a box	1 to 5 g	Small and medium cats	Box weight, capacity
Carrier on a scale	50 to 100 g	Cats used to carriers	Coarse error
Hold and subtract	100 g or more	Occasional checks	Coarse error, safety

For a cat you want to track closely, such as one on a weight plan or an older cat, invest in a baby or kitchen scale. A vet’s scale is another option; many practices allow free weigh-ins, and a nurse can record the weight.

Getting the cat to cooperate

Most cats accept weighing if it is calm and short.

Choose a quiet time, when the cat is relaxed, not just after a meal or play.
Leave the scale out, so the cat gets used to it, with a blanket on top.
Reward calm behaviour with a small treat within the daily allowance; see how many treats a cat can have.
Keep sessions short and stop if the cat is stressed.
Use a carrier or box with a lid for cats that hate open spaces.
Weigh at the same time and before meals.

If a cat will not accept any method, ask your vet’s practice about nurse weigh-ins, which can be a quick, low-stress visit.

How often and when

Cat	Frequency
Healthy adult	Monthly
Kitten	Weekly
Cat on a weight plan	Every one to two weeks, as the vet advises
Senior cat	Monthly or as the vet advises
Cat with a health condition	As the vet advises

Weigh in the morning before breakfast, after a toilet visit, and on the same day of the week. Do not weigh daily; day-to-day changes are noise.

Logging weights

Date	Method	Weight (kg)	Change since last	Change since start	Body condition	Notes

The Pet Weight Change Calculator turns two weights and a number of weeks into a percentage and weekly pace. The Pet Weight Converter switches between kilograms, pounds and ounces; see kilograms to pounds for pets.

Reading the trend and acting on it

A 4 kg cat that was 4.2 kg three months ago has lost 200 g, 4.8%. If you did not plan it, tell your vet. A cat that is gaining 50 g a month is gaining 1.2% a month, which over a year is nearly 15%. Cats should not lose weight quickly, since rapid loss can be dangerous in cats; a vet should supervise any plan. Our guide to senior cat care includes weighing in a monthly checklist, and the Cat Calorie Calculator shows daily energy for any weight.

Weight	Neutered adult (1.2 × RER)	Inactive adult (1.0 × RER)
3 kg	191 kcal	160 kcal
4 kg	238 kcal	198 kcal
5 kg	281 kcal	234 kcal
6 kg	322 kcal	268 kcal

Body condition as a check

Weight does not tell you whether a cat is too fat or too thin. Combine it with a look and a feel: ribs should be easy to feel under a thin layer of padding, with a waist behind them when viewed from above. Photograph your cat from above and the side each month. Ask your vet to show you the body condition scale for cats.

A worked example

Pip is a neutered cat. Her owner weighs her on a kitchen scale with a box on the first of each month.

Date	Weight	Change since last	Change since start
1 Jul	4.20 kg
1 Aug	4.25 kg	+1.2%	+1.2%
1 Sep	4.31 kg	+1.4%	+2.6%
1 Oct	4.38 kg	+1.6%	+4.3%

Each month’s change is small, but the trend is steady: 4.3% in three months. At 238 kcal a day she needs about 63 g of a 3,800 kcal/kg food. The owner checks: she has been getting about 70 g plus treats. She cuts the meals to 56 g with treats of 24 kcal inside the total, and keeps weighing. By the next quarter the weight has levelled. A scale that reads to 10 g made the early trend visible.

Common mistakes

Using a scale that reads to 100 g or more.
Weighing at different times or with different methods.
Forgetting to zero a box or carrier.
Weighing too often.
Ignoring slow, steady change.
Forcing a frightened cat.
Not telling the vet about a drift.

Quick summary

Use a baby scale, a kitchen scale with a tared box, a carrier on a scale or hold-and-subtract.
A 100 g error is 2.5% of a 4 kg cat, so choose a scale that reads to 10 to 50 g.
Weigh monthly (adults) or weekly (kittens), at the same time, with the same method.
Log the weights; a 5% change in a month, or a steady drift, deserves a call to your vet.
Do not push a cat to lose weight quickly; ask your vet.
Use the Pet Weight Change Calculator.

Frequently asked questions

How do I weigh a cat at home?

Put a box or carrier on a kitchen or baby scale, zero it, and place the cat inside. Or weigh yourself with and without the cat.

How accurate does a cat scale need to be?

A reading to 10 to 50 g is good. A 100 g error is 2.5% of a 4 kg cat, which hides a meaningful change.

How often should I weigh my cat?

Monthly for healthy adults, weekly for kittens, and as your vet advises for older cats or cats on a plan.

What change in weight should I report to the vet?

A loss or gain of 5% or more over a month, or a steady drift across several weighings. For a 4 kg cat, 5% is 200 g.

My cat will not stay on the scale. What can I do?

Use a carrier or a box with a lid, put a familiar blanket in it, and reward calm behaviour. Weigh the empty container first.

Is it normal for a cat's weight to vary day to day?

Yes, by a percent or two from food, water and toileting. Compare the same time of day and look at the trend.

Sources

Reviewed by the CalcuPaw Veterinary Review Team

Last reviewed 19 Oct 2026 · Meet the review team · This guide is general information, not veterinary advice.