How we calculate

Puppy weight calculator

The puppy weight calculator and the breed charts share one growth model, fitted separately for each of five size classes.

1. Correct for body condition. If you give a body condition score on the 9-point WSAVA scale, we first estimate the weight your puppy would have at an ideal score (5): ideal weight = weight ÷ (1 + 0.10 × (score − 5)). Each point away from 5 counts as about 10% of body weight; the 2021 AAHA nutrition guidelines use the same step for each point above 5 (see open question D6).
2. Pick a size class. A breed sets its class from the AKC adult range. Without a breed we test each class and keep the one whose own projection lands inside that class; if two fit, the result covers both.
3. Divide by the share of adult weight reached so far. Each class has three curves, for an early, a typical and a late maturing puppy. Adult range = today’s weight ÷ share on the early curve, up to today’s weight ÷ share on the late curve. The marked point uses the typical curve.
4. Compare with the breed. If you picked a breed, we show where the estimate falls against its AKC range and suggest mentioning it at your next visit when the marked point is more than 25% outside it.

The curves follow a Gompertz shape, a standard growth model in which the share of adult weight is f(t) = exp(−exp(−k × (t − t_i))). Each curve is set by two ages: when a puppy reaches half of its adult weight, and when it reaches 99%. Results stop at 104 weeks.

• Toy: Fitted to a published growth study of 65 Toy Poodles (Menchetti et al. 2020).
• Small: Estimated from published curves; to be refit. Set between the toy and medium curves.
• Medium: Estimated from published curves; to be refit.
• Large: Fitted to published Labrador Retriever growth data (Trangerud et al. 2007).
• Giant: Estimated from published curves; to be refit. Guided by Newfoundland data (Trangerud et al. 2007) and the WALTHAM charts.

Breed charts start from the AKC adult range instead of your puppy’s weight: at each age the low end is the bottom of the range times the late curve’s share, and the high end is the top times the early curve’s share. When the AKC gives only an upper weight (“up to 28 lb”), we set the bottom at 70% of it. That is our own assumption, and each affected breed page says so.

Size classes and life expectancy come from a 2023 study of dog life expectancy (Montoya et al.): toy under 12 lb, small 12–24 lb, medium 24–57 lb, large 57–99 lb, giant 99 lb or more.

Puppy growth chart

The growth chart draws the expected band for your puppy’s size class, week by week, from the same curves. Each weigh-in is marked as below, within or above the band. With two weigh-ins at least 2 weeks apart, we also compare the adult weight each one points to.

If that projected adult weight moves by 15% or more between weigh-ins, the chart suggests a vet check. The 15% trigger is our own choice, set as a stand-in for a puppy crossing centile lines on the WALTHAM charts.

Dog age calculator

The dog age calculator shows the span between two published methods, so you can see how far they disagree.

• Epigenetic estimate (Wang et al. 2020, a study of 104 Labrador Retrievers): human years = 16 × ln(dog years) + 31.
• Traditional estimate (the AVMA rule as quoted by the AKC): 15 human years for the first year, 9 more for the second, then a fixed number per year that depends on size. Below 1 year we scale the first 15 years evenly; that step is ours.

The yearly step after age 2 is 5 human years for a medium dog, scaled by how long each size class lives (Montoya 2023): step = 5 × medium life expectancy ÷ class life expectancy. That gives toy 4.75, small 4.69, medium 5.00, large 5.52, giant 6.68. The scaling is our own.

Life stages: puppy until 12 months for toy to medium dogs and 18 months for large and giant dogs (VCA), young adult until 4 years, and senior for the last quarter of the expected life span (AAHA 2019, read through a secondary source; see D9). Using each class’s life expectancy, senior starts at toy 10.0 years (of 13.4), small 10.2 years (of 13.5), medium 9.5 years (of 12.7), large 8.6 years (of 11.5), giant 7.1 years (of 9.5).

Dog food calculator

Daily calories start from the resting energy requirement (Merck Veterinary Manual): RER = 70 × (body weight in kg)^0.75, using the ideal weight from the body condition step above. RER is then multiplied by the AAHA 2021 factor range for the dog’s life stage and activity:

• Neutered adult × 1.4–1.6, intact adult × 1.6–1.8, inactive or prone to weight gain × 1.0–1.2.
• Light work × 1.6–2.0. Moderate work × 2.0–3.0; AAHA’s range goes higher, and for heavier work we suggest asking your vet.
• Seniors: the range × 0.8, from the National Research Council’s note that older dogs need about 20% fewer calories.
• Where AAHA gives one value instead of a range (growth, weight loss), we show 0.9–1.1 times that value. That spread is our own.

Cups or grams come from the calorie count on your food’s label. Treats should stay under 10% of daily calories (VCA). For a dog with a body condition of 7 or more we show a starting point only (RER × 1.0 at the ideal weight) and ask you to see your vet. We do not calculate calories for pregnant or nursing dogs.

Puppy feeding chart

A growing puppy needs RER × 3.0 until about 4 months (17.4 weeks) and RER × 2.0 after that (AAHA 2021, Merck), shown as 0.9–1.1 times the value. Later rows project the puppy’s weight along the typical growth curve, in 4-week steps up to 1 year.

Meals per day follow the AKC: 4 until 12 weeks, 3 until 6 months, then 2. Where the AKC schedule leaves the exact week of each change open, the cut-off is ours. The switch to adult food: at 7–9 months for dogs under 20 lb as adults, and 12–14 months for bigger dogs (VCA / CAVN).

Chocolate toxicity calculator

Dose (mg per kg of body weight) = grams eaten × methylxanthines per gram ÷ dog’s weight in kg. Methylxanthines are the stimulants in cocoa, mainly theobromine and caffeine. Per gram, from the Merck Veterinary Manual and USDA FoodData Central (we take the span of both where both give a value):

Merck’s dose levels: mild signs from 20 mg/kg, heart effects from 40–50 mg/kg, seizures from 60 mg/kg, and a lethal dose for half of dogs at 100–200 mg/kg. We use bands at 20, 40, 60 and 100 mg/kg and place you by the high end of your dose range. If you don’t know the type, we count dark chocolate (70–85%) and say so; that isn’t the worst case, so the form asks you to pick baking chocolate or cocoa powder if it could be either. Every result above the lowest band tells you to call a poison line or go to an emergency vet now.

Dog pregnancy calculator

Due-date windows depend on which date you know. A mating date gives the widest window: the Merck Veterinary Manual gives the outer window and VCA the narrower, most likely one. The other windows count from a hormone test or a smear (Merck). The ovulation window is our own, worked out from the LH-peak window (see D11).

An ultrasound before about day 21 can miss a pregnancy, and an X-ray shows the skeletons from about day 42 (VCA). More than 70 days after a known mating, the tool tells you to call your vet (Merck, dystocia).

How we check numbers

• Every figure the calculators use sits in a data file next to its source, the web address and the date we read it. The tables on this page and on the sources page are generated from those files when the site is built, so they cannot drift from what the calculators use.
• Each source carries a status. Of 34 sources, 25 were checked against the original, 8 through a secondary source such as a press release or a quote, and 1 not yet.
• 59 worked examples, calculated by hand from the formulas on this page, run against the calculator code before every release. If an example and the formula disagree, we keep the formula and write down why.
• Wherever a step is our own choice rather than a published figure, this page says so.
• We recheck every source at least once a year, and the date at the top of this page changes only after every formula and source has been checked again.

Open questions

These are the points we have not been able to confirm yet, and what each one changes. We will update this list as we resolve them.

D1 The AKC breed chart gives separate male and female weights for only two breeds (Standard Poodle and Giant Schnauzer).

Breed charts use one combined range and do not split males from females.

D2 Our breed list holds the AKC web address of each breed page, and we have opened only a few of them so far.

Breed weights come from the AKC chart, which we did check. Only the links to single AKC breed pages may be out of date.

D3 The AKC chart’s values for Beagle, Pembroke Welsh Corgi, Boxer and Cane Corso could not be read as a clean range.

We took Beagle, Corgi and Boxer from their own AKC breed pages. We could not confirm a weight for the Cane Corso, so the calculator has no Cane Corso option yet.

D4 The 2017 growth standard charts (Salt et al.) publish their centiles as curves, not as numbers we can use.

Small, medium and giant growth curves are estimated from published curves; to be refit when we can work from the raw data.

D5 The Toy Poodle study reports a growth rate of 11.8%. We read it as a weekly rate; the full text may say otherwise.

The age at which a toy puppy is treated as full grown could shift.

D6 The 2021 AAHA guidelines treat each body condition point above 5 as about 10% extra weight; we have not read the 1997 study behind it, and no source we read gives the step for thin dogs below 5.

The ideal-weight correction in the puppy weight and dog food calculators, mainly for underweight puppies.

D7 The Merck Veterinary Manual does not say whether its chocolate dose levels count theobromine alone or theobromine plus caffeine.

We apply them to both together, which gives the higher, more cautious dose.

D8 The ASPCA Animal Poison Control page does not state its consultation fee.

The chocolate tool says only that a fee may apply.

D9 We could not open the full text of the AAHA 2019 Canine Life Stage Guidelines.

Life stage cut-offs in the dog age calculator come from a secondary summary.

D10 We used the AVMA dog-age rule as the AKC quotes it, not from the AVMA itself.

The traditional dog-years estimate rests on a secondary source.

D11 The commonly quoted “63 days from ovulation” is not stated in the Merck Veterinary Manual pages we read.

The due-date window counted from ovulation is worked out from the LH-peak window.

D12 The WSAVA adult calorie table does not match its own footnote.

We use it only to cross-check the dog food calculator, never to produce a result.

D13 We have no sourced range of calories per cup for dry food in general; the one study we found covers weight-control foods only.

We quote that range only for weight-control foods, and the dog food calculator shows cups only after you enter the number from your bag.

D14 We have not confirmed sourced figures for a safe weight-loss rate or for how often older dogs should see a vet.

Our answers on these topics give no numbers.

D15 The note about raisins, macadamia nuts and xylitol in the chocolate tool still needs its source confirmed.

The wording of the low-risk chocolate result.

D16 We found no study that links paw size to adult size.

We removed paw size from our answers.

Corrections

If a number, formula or statement looks wrong, email hello@puprange.com with the page address, what you think is wrong and, if you have one, a source. We aim to reply within 7 days.

When a fix changes a result or a safety message, we add a dated note to the page it affects saying what changed and why, and list it here. Small layout or wording fixes don’t get a note. See our editorial policy for how we choose sources.

Corrections so far: none.