Puppy Scale
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The register

Data and sources, every one dated.

Every dataset behind the calculators: where it comes from, its licence, its version and the date we last checked it against the source.

  1. Cat age: the 2010 AAFP-AAHA human-age chart and the 2021 life stages

    Source
    AAFP-AAHA Feline Life Stage Guidelines 2010; AAHA/AAFP 2021
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 55036e19a48a…55036e19a48a0dcd5391c43089cc051e5336f0e2193c916758443ff6294a26f7

  2. Dog age: epigenetic clock, the classic rule, life stages and lifespans

    Source
    Wang et al. 2020; UC Davis; AAHA 2019; AVMA; Urfer 2020; McMillan 2024
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 0cbfb8e2bc59…0cbfb8e2bc591c3132c2af636ff1988e4d6850b85c344c270bc1f15237214bd8

  3. Breed figures used to pick a growth size class (CC BY sources only)

    Source
    Andersson 2023; O’Neill 2023/2026 (VetCompass); Bannasch 2021; Hayward 2016; Salt 2017 Table 1
    Version
    compiled 2026-10-07
    Checked
    a fixed, published dataset
    Licence
    CC BY 4.0
    File checksum
    SHA-256 f800f96809ee…f800f96809eeafd347ac784def6a7df207e6ea5790e2ab175151b3c3eb839a6c

    Breed weights: Andersson L, Emanuelson U, Ringmark S, Bjørnvad CR, Hedhammar Å, Höglund K (2023) Scientific Reports 13:443, doi:10.1038/s41598-022-27055-4; O’Neill DG, McMillan KM, Church DB, Brodbelt DC (2023) PLOS ONE 18(7):e0288081, doi:10.1371/journal.pone.0288081; O’Neill DG, Curtis TJ, York GOJ, Brodbelt DC, Church DB, Engdahl KS (2026) Canine Medicine and Genetics 13:4, doi:10.1186/s40575-026-00152-7; Bannasch D et al. (2021) Canine Medicine and Genetics 8:12, doi:10.1186/s40575-021-00111-4; Hayward JJ et al. (2016) Nature Communications 7:10460, doi:10.1038/ncomms10460 — all CC BY 4.0. Size classes: Salt C et al. (2017) PLOS ONE 12(9):e0182064, Table 1, CC BY 4.0.

  4. ASPCA “Cutting Pet Care Costs” line items (2021 update)

    Source
    ASPCA
    Version
    2021 update (no newer edition on 2026-10-07)
    Checked
    checked when a new survey is due
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 e7600e1430a1…e7600e1430a16668a647f12d8dc07e6da731cc1a9b79b50dded3e2bc2319bba4

  5. Published cost ranges for comparison (dated; never used as defaults)

    Source
    Rover; Synchrony; NAPHIA; AVMA; APPA; BLS
    Version
    read 2026-10-07
    Checked
    checked when a new survey is due
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 e7600e1430a1…e7600e1430a16668a647f12d8dc07e6da731cc1a9b79b50dded3e2bc2319bba4

  6. Energy equations (RER, NRC growth, gestation and lactation reference equations, modified Atwater)

    Source
    Merck; AAHA; NRC 2006 (via FEDIAF 2025 and peer-reviewed papers); AAFCO/state rules
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 f64e0cc124bd…f64e0cc124bd9e55d5ed22ca27e1c6c1262004d14a32f999ebbecb6ee100cbe2

  7. Daily energy factors (multiples of RER) for dogs and cats

    Source
    AAHA 2021 Nutrition and Weight Management Guidelines (Box 1); Merck; WSAVA
    Version
    AAHA 2021 (read 2026-10-07)
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 71c448de10c6…71c448de10c6038692c791bbde0981c38f1a55997a656e6141a5312804d9623e

  8. Pet-food label calorie statement and food-amount inputs

    Source
    AAFCO; Kentucky 12 KAR 3:042; Wisconsin ATCP 42; FDA (archived)
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced

  9. Puppy weight centile lines by size class, sex and week (derived)

    Source
    University of Liverpool DataCat 377 (Salt et al. 2017 data)
    Version
    derived 2026-10-07 (Table 1 size classes, N23)
    Checked
    a fixed, published dataset
    Licence
    CC BY 4.0
    File checksum
    SHA-256 037805e35e5d…037805e35e5d49bc17c418cef725b91c7a64857762c50891e5a84069f3c0ec83

    Salt C, Morris PJ, German AJ, Wilson D, Lund EM, Cole TJ, Butterwick RF (2017) Growth standard charts for monitoring bodyweight in dogs of different sizes - SUPPORTING DATA. University of Liverpool DataCat, doi:10.17638/datacat.liverpool.ac.uk/377, licensed CC BY 4.0. Paper: Salt C et al. (2017) PLOS ONE 12(9):e0182064, doi:10.1371/journal.pone.0182064.

  10. Age at which the median puppy reaches 50/75/90/95% of adult weight, by size class (derived)

    Source
    University of Liverpool DataCat 377 (Salt et al. 2017 data)
    Version
    derived 2026-10-07 (Table 1 size classes, N23)
    Checked
    a fixed, published dataset
    Licence
    CC BY 4.0
    File checksum
    SHA-256 2f1d1d258330…2f1d1d2583309b0a1e805176ed6f3a9b1bb7b9a1abf984a348934834adc52a62

    Salt C, Morris PJ, German AJ, Wilson D, Lund EM, Cole TJ, Butterwick RF (2017) Growth standard charts for monitoring bodyweight in dogs of different sizes - SUPPORTING DATA. University of Liverpool DataCat, doi:10.17638/datacat.liverpool.ac.uk/377, licensed CC BY 4.0. Paper: Salt C et al. (2017) PLOS ONE 12(9):e0182064, doi:10.1371/journal.pone.0182064.

  11. Puppy weight as a share of adult weight, by size class and age (derived)

    Source
    University of Liverpool DataCat 377 (Salt et al. 2017 data)
    Version
    derived 2026-10-07 (Table 1 size classes, N23; G-MONO applied)
    Checked
    a fixed, published dataset
    Licence
    CC BY 4.0
    File checksum
    SHA-256 78276ae27d28…78276ae27d28f4109a8391608c73f6b974b77fd5f51b11fdccad57b2485e7b16

    Salt C, Morris PJ, German AJ, Wilson D, Lund EM, Cole TJ, Butterwick RF (2017) Growth standard charts for monitoring bodyweight in dogs of different sizes - SUPPORTING DATA. University of Liverpool DataCat, doi:10.17638/datacat.liverpool.ac.uk/377, licensed CC BY 4.0. Paper: Salt C et al. (2017) PLOS ONE 12(9):e0182064, doi:10.1371/journal.pone.0182064.

  12. How far the folk rules (“double the weight at 16 weeks” …) miss, by size class (derived)

    Source
    University of Liverpool DataCat 377 (Salt et al. 2017 data)
    Version
    derived 2026-10-07 (Table 1 size classes, N23)
    Checked
    a fixed, published dataset
    Licence
    CC BY 4.0
    File checksum
    SHA-256 0f6a71272807…0f6a7127280756d6bbec847e823d1446df7025ec8b33e5095d823bb578916e62

    Salt C, Morris PJ, German AJ, Wilson D, Lund EM, Cole TJ, Butterwick RF (2017) Growth standard charts for monitoring bodyweight in dogs of different sizes - SUPPORTING DATA. University of Liverpool DataCat, doi:10.17638/datacat.liverpool.ac.uk/377, licensed CC BY 4.0. Paper: Salt C et al. (2017) PLOS ONE 12(9):e0182064, doi:10.1371/journal.pone.0182064.

  13. Kitten weight centile lines by sex and week (derived)

    Source
    University of Liverpool DataCat 1456 (Salt et al. 2022 data)
    Version
    derived 2026-10-07
    Checked
    a fixed, published dataset
    Licence
    CC BY 3.0
    File checksum
    SHA-256 fae1a58d4d52…fae1a58d4d52d47854313d40aefb0a6852bbab32245f93436fa1f88803ec960b

    German A, Salt C, Butterwick R (2021) Growth standard charts for monitoring bodyweight in Domestic Shorthair kittens - SUPPORTING DATA. University of Liverpool DataCat, doi:10.17638/datacat.liverpool.ac.uk/1456, licensed CC BY 3.0. Paper: Salt C, German AJ, Henzel KS, Butterwick RF (2022) PLOS ONE 17(11):e0277531, doi:10.1371/journal.pone.0277531.

  14. Kitten weight as a share of adult weight, by age (derived, research colony)

    Source
    University of Liverpool DataCat 1456 (Salt et al. 2022 data)
    Version
    derived 2026-10-07
    Checked
    a fixed, published dataset
    Licence
    CC BY 3.0
    File checksum
    SHA-256 8cfe5fdbd8fb…8cfe5fdbd8fb5550263e60cf5fe33abb92e84223985fa706d03f52ca3c67d0af

    German A, Salt C, Butterwick R (2021) Growth standard charts for monitoring bodyweight in Domestic Shorthair kittens - SUPPORTING DATA. University of Liverpool DataCat, doi:10.17638/datacat.liverpool.ac.uk/1456, licensed CC BY 3.0. Paper: Salt C, German AJ, Henzel KS, Butterwick RF (2022) PLOS ONE 17(11):e0277531, doi:10.1371/journal.pone.0277531.

  15. Dog heat cycle intervals and stages

    Source
    Merck Veterinary Manual; Threlfall (dvm360)
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 b4974138decc…b4974138deccfa5b130ab141d0321cea424c7a9294b38ab9c6bfc90706b99fda

  16. When to call the vet during whelping or queening (professional thresholds)

    Source
    Merck Veterinary Manual (professional); Musters 2011
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced

  17. Dog pregnancy milestones by day after the LH surge (paraphrased)

    Source
    Concannon 2000 (IVIS); Merck
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 aeec600a4ca2…aeec600a4ca219c623668b48e51feea02c1ee049d06227a1d69303ac29fb6583

  18. Due-date reference points and windows (dog and cat)

    Source
    Merck Veterinary Manual; Concannon 2000; Siena & Milani 2021; Root Kustritz 2006
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 b1a388546511…b1a38854651166982071752b5a2c00fa7409d4db90a36d4b07b164abc8d6fb0c

  19. Chocolate: methylxanthines per ounce and the dog dose bands

    Source
    Merck Veterinary Manual; USDA FoodData Central; ASPCA
    Version
    Merck full review Sept 2024, updated Feb 2026; FDC read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 89627a3157c8…89627a3157c8d43d706081b705a3b86a43ebb2615fe134212f7f7ee4bc2b417d

  20. Animal poison-control hotlines (U.S.)

    Source
    ASPCA Animal Poison Control Center; Pet Poison Helpline
    Version
    read 2026-10-07
    Checked
    checked at least every 35 days
    Licence
    Facts cited with a link; text and tables not reproduced
    File checksum
    SHA-256 26352c5f25d9…26352c5f25d9a8aaf639b12626dc94a653545b52b4e6f30565df9bc34f897c5d

  21. Toxins with no safe number: the call-now cards

    Source
    Merck Veterinary Manual; ASPCA; Pet Poison Helpline; peer-reviewed papers
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced

  22. Water intake: the “too much” thresholds and typical total water

    Source
    Pavlovsky 2026 (CC BY review); Washabau & Day 2013; NRC 2006 via CC BY papers; cat case reports
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced

  23. Body condition score (1–9), ideal-weight method and weight-loss rules

    Source
    WSAVA; AAHA 2021 and 2014; Merck; German et al. 2009
    Version
    read 2026-10-07
    Checked
    checked at least every 90 days
    Licence
    Facts cited with a link; text and tables not reproduced

Updates and corrections

  • — (https://www.aspca.org/pet-care/animal-poison-control → https://www.aspca.org/pet-care/aspca-poison-control)
  • — (Green discharge before the first puppy. → Green discharge (Merck lists green discharge during labor as abnormal).)
  • —
  • — (surveyDate 2026-05, n 1000 → researchEdition 2026)
  • — (class by breed average adult weight (< 6.5 kg → I) → class by Salt 2017 Table 1 (6 / 8 / 5 lightest breed codes → I / II / III))
  • —

Data licences

Growth bands derived by Puppy Scale from Salt C et al. (2017), PLOS ONE 12(9):e0182064, data: University of Liverpool DataCat 377, licensed CC BY 4.0. Our tables are empirical summaries, not the published model curves. Changes: see the method.

Kitten bands derived by Puppy Scale from Salt et al. (2022), data: University of Liverpool DataCat 1456, licensed CC BY 3.0. Our tables are empirical summaries, not the published model curves.

Breed weights: Andersson L et al. (2023) Scientific Reports 13:443 (CC BY 4.0); Bannasch D et al. (2021) Canine Medicine and Genetics 8:12 (CC BY 4.0). Kennel-club breed standards: see the club’s own breed page.

Questions about a dataset? Write to us from the contact page.