How often should I recalculate the ration while the animal grows?

Between two and six months the ration should be revised every two weeks, because requirement follows weight and weight changes fast in that phase. Between six and twelve months a monthly review is enough. The reference is not only current weight but also body condition: if ribs become hard to palpate, reduce the amount even when weight is following the expected curve, because excessive rapid growth is a documented orthopaedic risk factor in large breeds.

My puppy will not stay on the scale: what do I do?

Use a low basket with raised sides as the tare, or put a familiar towel on the platform. If that still fails, use the indirect method: weigh yourself, then weigh yourself holding the animal and subtract, repeating twice and using the average. The indirect method is only reliable above five kilograms and at a resolution of one hundred grams or better, because the errors of the two readings add together.

The clinic weight differs from mine: which one do I record?

Record both, noting the source. Different scales are calibrated differently and a discrepancy of a few per cent is normal. The rule is to compare values measured on the same instrument: your home series is what shows the slope, the clinic weight is what the vet uses for drug dosing. Do not convert or adjust values by eye, because an arbitrary correction makes the series less reliable than keeping two separate ones.

Up to what age does an animal keep growing?

It depends mainly on expected adult size. Small breeds reach adult weight between ten and twelve months, medium breeds around twelve months, large breeds between fifteen and eighteen months, and giant breeds sometimes at twenty four months. Domestic cats usually finish growing between ten and twelve months, with some large format breeds continuing longer. Monthly weighing stays useful afterwards as the adult baseline.

Do I need to record body condition as well, or is weight enough?

You need both, because they measure different things. Weight records total mass, body condition on a nine point scale describes how that mass is distributed. An animal can gain weight and worsen its body condition, for example by losing muscle and adding fat. Assessing the ribs, the waist from above and the abdominal profile takes twenty seconds and should be done monthly, with the score written next to the weight.

The first months10 minLevel: BeginnerUpdated on July 26, 2026

Weighing a puppy or kitten and recording growth properly

Scale resolution, a six step procedure, weighing frequency by age and the weight changes that justify a phone call to the clinic today.

Audience: Pet owners
Species: Dog, Cat
Scope: Valid everywhere

What you need before you start

Una bilancia con risoluzione adeguata al peso attuale, tenuta sempre nello stesso punto della casa
Un contenitore rigido o un asciugamano da usare come tara per gli animali che non stanno fermi
Un unico posto dove annotare data, ora e peso, sempre lo stesso per tutti i mesi
Il peso dichiarato al momento della consegna, da usare come punto di partenza della curva

Body weight is the cheapest and most informative measurement of the first months: it costs ten seconds, needs no needles, and flags many problems days before they show up as a refused meal. The catch is that a weight only counts if it can be compared with the previous one. A measurement taken on a full stomach on Monday and an empty one on Thursday, on two different scales at two different times of day, produces a difference that says nothing about growth and a great deal about measurement conditions. This guide sets out the resolution each size needs, the procedure that produces comparable numbers, the correct frequency for each age, and how to tell when the curve is saying something clinical.

Why weight is measured and not estimated

Anyone who sees an animal every day cannot perceive gradual change: a ten per cent loss spread over three weeks is invisible by eye and obvious on a scale. In a growing animal the sensitivity is even higher, because growth should be continuous and any interruption is a signal. Weight also serves three very concrete purposes that have no substitute.

Calculating the daily ration, which in a growing animal changes every two or three weeks.
Determining the weight band for parasite products, which shifts quickly in the first months.
Giving the vet a time series instead of one isolated value taken on the day of the visit.
Catching weight loss while it can still be corrected by adjusting the diet.

Which scale you need and at what resolution

The rule of thumb is that scale resolution should not exceed 0.5 per cent of the animal's weight. For a 400 gram kitten that means a kitchen scale reading to 1 gram: a bathroom scale that steps in 100 gram increments hides an entire day of growth.

Minimum recommended resolution by weight band
Animal weight	Useful resolution	Typical instrument
up to 1 kg	1 gram	Kitchen scale with a wide platform
1 to 5 kg	5 to 10 grams	Baby scale or kitchen scale up to 5 kg
5 to 15 kg	20 to 50 grams	Baby scale or luggage scale with a sling
15 to 40 kg	100 grams	Digital bathroom scale, animal still at the centre
over 40 kg	100 to 500 grams	Digital bathroom scale or the clinic platform

Always put the scale on the same rigid surface: carpet can shift the reading by several hundred grams.
Check the zero before every weighing, with the platform empty and the scale already switched on for a few seconds.
Verify accuracy once a month with an object of known weight, for example a sealed 1 kilogram pack.
If you change scales, take one overlap measurement on both the same day and record the offset.

The six step procedure

Pick a fixed time and never change it
The best moment is the morning, before the first meal and after the first elimination. Between a full and an empty stomach a small animal can differ by five per cent, which is more than it grows in a week. A constant time removes that noise at no cost.
Set the tare before you pick up the animal
Put the container or towel you will use on the platform and zero the reading. For a puppy or kitten that will not stay still, a low basket with raised sides works better than any attempt to hold it in place. Always use the same container, so the tare stays identical even on a day you forget to zero.
Place the animal at the centre of the platform
The full weight must rest on the scale: one paw off the platform or a hand resting on the back distorts the reading unpredictably. If you must steady the animal, keep an open hand at its side without pushing down or lifting.
Wait for a stable reading and actually read it
Digital scales show a value that fluctuates for a few seconds before settling. Wait for the stability indicator and read the whole number, decimals included. If the animal never settles, use the dynamic weighing function if the scale has one, or move to the indirect method in the next step.
Use the indirect method if needed
Step on the scale alone, note the value, then step on again holding the animal and subtract. This works only at 100 gram resolution or better and only for animals above 5 kilograms, because the errors of the two readings add up. Repeat the pair of measurements twice and use the average.
Write down weight, date and time straight away
Record the value before putting the animal down, not afterwards. Add the time, whether it was before or after a meal, and any relevant event that day such as a vaccination or an episode of diarrhoea. A weight without context is worth half a weight logged with two words of background.

How often to weigh, by age

Weighing too often produces noise: daily swings from meals, hydration and elimination exceed the real increment and generate false alarms. Weighing too rarely means finding a problem weeks late. The frequency below is the compromise normally used in practice.

Weighing frequency and growth references
Age	How often	Indicative reference
0 to 3 weeks	every day, always at the same time	a kitten gains roughly 10 to 15 grams a day
3 to 8 weeks	twice a week	a puppy doubles its birth weight within 8 to 10 days
2 to 6 months	once a week	fastest growth phase, recalculate the ration every two weeks
6 to 12 months	every two weeks	small breeds approach adult weight between 10 and 12 months
over 12 months	once a month	large breeds finish growing between 15 and 24 months

Read the slope, not the single number

An isolated value says little. What matters is the direction of the series and its slope: an animal growing more slowly than expected but still growing, and an animal flat for ten days, are completely different situations even when today's weight is identical. Always compare at least three consecutive measurements before drawing conclusions.

How to read the change between two weighings
Observation	How to read it	What to do
Steady regular growth	Ration is adequate	Recalculate the ration every two weeks
Growth slowing as age increases	Physiological, the curve flattens towards adulthood	No action, keep measuring
Weight flat for more than 7 days under 6 months	Abnormal during rapid growth	Contact the clinic and bring the log
Drop of more than 5 per cent between two weighings	Always significant, at any age	Telephone the same day
Rapid gain with a rounding abdomen	Possible excess ration or fluid accumulation	Assess body condition and ask for a check

Note any food change next to the weight, because a transition often produces one slower week of growth.
Mark with a symbol any weighing taken in unusual conditions, for example after a meal, so you do not compare it with the rest.
Bring the full series to the appointment: the slope of the last two months is more useful than any single value.
Keep the weights recorded at the clinic too, noting that they come from a different scale than yours.

Mistakes that make the data unusable

Mistake, effect on the data and correction
Mistake	Effect	Correction
Weighing at a different time every day	Swings of up to 5 per cent unrelated to growth	Always in the morning, before the meal
Scale placed on carpet or flexing floorboards	Lower readings that cannot be repeated	Rigid surface, always the same one
Rounding the value to the nearest half kilogram	The signal disappears in the early weeks	Record the full value with decimals
Changing scale without noting it	An artificial step in the curve	Overlap measurement and a note in the log
Holding the animal without subtracting your own weight	A meaningless number	Tare with a container, or repeat the indirect method twice
Logging from memory at the end of the day	Transcription errors and missing values	Write it down before putting the animal back down

When weight becomes a clinical signal

In a growing animal there is no such thing as physiological weight loss. Any drop, however small, is a value that needs explaining rather than waiting out. The situations below justify a phone call without waiting for the appointment already in the diary.

Any weight loss in an animal under twelve months, even with no other signs.
Weight unchanged for more than seven consecutive days before six months of age.
A drop of more than five per cent between two consecutive weighings, at any age.
Normal growth but worsening body condition, with ribs becoming steadily more prominent.
Rapid weight gain with a tense abdomen, which must be told apart from simple overfeeding.
Weight falling alongside increased appetite, a combination that always needs investigating.

Frequently asked questions

How often should I recalculate the ration while the animal grows?: Between two and six months the ration should be revised every two weeks, because requirement follows weight and weight changes fast in that phase. Between six and twelve months a monthly review is enough. The reference is not only current weight but also body condition: if ribs become hard to palpate, reduce the amount even when weight is following the expected curve, because excessive rapid growth is a documented orthopaedic risk factor in large breeds.
My puppy will not stay on the scale: what do I do?: Use a low basket with raised sides as the tare, or put a familiar towel on the platform. If that still fails, use the indirect method: weigh yourself, then weigh yourself holding the animal and subtract, repeating twice and using the average. The indirect method is only reliable above five kilograms and at a resolution of one hundred grams or better, because the errors of the two readings add together.
The clinic weight differs from mine: which one do I record?: Record both, noting the source. Different scales are calibrated differently and a discrepancy of a few per cent is normal. The rule is to compare values measured on the same instrument: your home series is what shows the slope, the clinic weight is what the vet uses for drug dosing. Do not convert or adjust values by eye, because an arbitrary correction makes the series less reliable than keeping two separate ones.
Up to what age does an animal keep growing?: It depends mainly on expected adult size. Small breeds reach adult weight between ten and twelve months, medium breeds around twelve months, large breeds between fifteen and eighteen months, and giant breeds sometimes at twenty four months. Domestic cats usually finish growing between ten and twelve months, with some large format breeds continuing longer. Monthly weighing stays useful afterwards as the adult baseline.
Do I need to record body condition as well, or is weight enough?: You need both, because they measure different things. Weight records total mass, body condition on a nine point scale describes how that mass is distributed. An animal can gain weight and worsen its body condition, for example by losing muscle and adding fat. Assessing the ribs, the waist from above and the abdominal profile takes twenty seconds and should be done monthly, with the score written next to the weight.

What to do next

Choose a scale with resolution within 0.5 per cent of current weight, weigh every time in the morning before the meal and on the same rigid surface, and write the full value down before putting the animal back on the floor. Compare at least three consecutive measurements before worrying, but call the same day if the drop exceeds five per cent or if weight stays flat for a week under six months of age.