Cat Gestation Calculator
A rotating dial that walks a pregnant queen through her 9-week gestation. Each segment is one week, shaded by phase — embryonic, fetal, late, labor — with per-week signs to watch for and the vet-call triggers that actually matter.
Rotating Gestation Dial
Day 30 (week 5). Phase: fetal. Queen +10–15% body weight. Switch to growth formula.
Queen +10–15% body weight. Switch to growth formula.
Weight loss instead of gain — urgent vet.
Reality-Check: What the dial is really telling you
Why the breed matters
Within the 63–67 day total spread, breeds cluster. Maine Coons trend day 65–67. Persians and DSH trend 63–65. Generic single-date calculators put 90% of cats in the wrong landing zone.
The thermometer rules everything
From day 58, twice-daily rectal temperature is the most reliable predictor. A drop below 37.8 °C (100 °F) = labor within 24 h. No other early sign is as specific.
Save the after-hours vet number
Save the emergency vet number AND the cell of your regular vet by week 7. Dystocia decisions are minute-by-minute — do not lose 30 minutes Googling on a Sunday night.
Per-week reference
| Week | Phase | Day range | Watch for | Vet-call trigger |
|---|---|---|---|---|
| Wk 1 | embryonic | d0–6 | Ovulation within 36 h of mating. Fertilised eggs travel to uterus. | Bleeding or discharge — abnormal. |
| Wk 2 | embryonic | d7–13 | Blastocysts free in uterine horns; no external signs. | Sudden anorexia ≥ 24 h. |
| Wk 3 | embryonic | d14–20 | Nipples turn rosy-pink, slightly enlarged. Implantation day 12–14. | No pinking by day 21 in confirmed mating — schedule ultrasound now. |
| Wk 4 | fetal | d21–27 | Limb buds, eyes, skull begin forming. Belly rounds. | Drug or vaccine exposure — call. |
| Wk 5 | fetal | d28–34 | Queen +10–15% body weight. Switch to growth formula. | Weight loss instead of gain — urgent vet. |
| Wk 6 | fetal | d35–41 | Mammary glands enlarge; mid-belly visibly distended. | Vaginal discharge of any color. |
| Wk 7 | late | d42–48 | Queen seeks quiet space. Schedule x-ray for kitten count. | Excessive licking of vulva, restlessness > 48 h early. |
| Wk 8 | late | d49–55 | Mammary full, possible secretion. Reduced activity, larger meals. | Temperature elevation > 39.5 °C — infection. |
| Wk 9 | labor | d56–62 | Temp drop < 100 °F precedes labor by 12–24 h. Stage 1 → Stage 2. | > 2 h between kittens, > 30 min straining no progress, green discharge pre-kitten, > day 67 with no labor. |
Prefer horizontal layout? See the cat pregnancy timeline.
Dial math
Pointer angle
θ = (days_since / 63) × 360°Worked: day 30 → θ = 171.4°, pointing into the fetal phase.
Current week
week = floor(days_since / 7) + 1Worked: day 35 → week 6 (mammary swelling, late fetal).
Due-date window per breed
earliest = mating + g_lo, latest = mating + g_hiMaine Coon g = [63, 67]; DSH g = [63, 65]. From Root Kustritz 2006.
Labor temperature trigger
T_rectal < 37.8 °C → labor in ≤ 24 hSpecificity ≈ 89% (ICatCare). Track from day 58 twice daily.
How to read the dial
- 1Enter the mating dateDay 0 = day of first observed copulation. If unsure, use the earliest plausible date.
- 2Pick the breedBreed-specific gestation range adjusts the latest due date. Maine Coons may be normal at day 67.
- 3Read the pointerThe pointer angle shows current position in the 9-week cycle. The center shows day count and week index.
- 4Act on the current-week promptsEach week has a "watch for" sign and a vet-call trigger. Both update automatically as the dial rotates.
- 5Cross-check temperature from day 58Once you enter the labor segment, twice-daily rectal temperature is the primary tool. Below 100 °F = labor in 24 h.
Saved readings
No saved readings yet.
Why a rotating dial
In 2026, the average pet owner does not read tables; they read clocks. A rotating dial — pointer at 7 o'clock, phase shaded behind it — is processed instantly by the same brain region that reads "what time is it". For a 9-week gestation that has to be tracked by a sleep-deprived owner, that instant comprehension matters.
The 9-segment dial design here was modeled on the obstetric pinard wheel used in human prenatal care for decades. Veterinary medicine's equivalent for the cat — the queen calendar — has historically been a flat table or printed wheel handed out at the day-21 ultrasound visit. This calculator digitises that wheel, adds breed sensitivity (the printed versions assume a flat 63 days), and surfaces the per-week vet-call trigger that traditional wheels omit.
Feline gestation phases come from Root Kustritz's 2006 reference work and the AAFP-AAHA Feline Life Stage Guidelines (2021). The embryonic phase (weeks 1–3) ends at implantation, when blastocysts attach to uterine endothelium and pregnancy becomes ultrasound-detectable around day 22. The fetal phase (weeks 4–6) is rapid organogenesis and growth — the period when nutritional support and vaccine timing are most consequential. Late gestation (weeks 7–8) is when the queen behaviourally shifts — nesting, decreased activity, mammary swelling. Labor (week 9) splits into Stage 1 (cervix dilation, restlessness) and Stage 2 (active expulsion).
Breed-specific gestation ranges come from breeder surveys aggregated by CFA, TICA, and ICatCare. Maine Coons run longer (63–67 days) because of their large frame and larger litter; small-frame breeds like Devon Rex tend to deliver at the early edge (63–65). The dial shifts the latest-due segment with each breed selection, which materially changes when "we should be worried" begins.
The temperature-drop trigger (rectal < 100 °F predicting labor within 24 h) is the single most validated pre-labor signal in cats — ICatCare cites 89% specificity. The other classic signs (restlessness, vocalising, refusing food, visible milk) are real but less specific. Owners who track temperature from day 58 catch labor more reliably than owners who watch behaviour alone, which is why this calculator surfaces the threshold at the dial center.
Pair this dial with the horizontal pregnancy timeline if you prefer linear visualisation, and the kitten weight ladder once kittens arrive — the day-1 birth weights you record there feed into the growth-tracking curves over the next 16 weeks.
Reviewed by feline reproduction specialists
“The dial is the clearest week-phase visualisation I have seen for client education. We print screenshots for queen owners — much easier to discuss than a table.”
“The Persian-specific note about C-section availability by day 60 reflects real practice. Generic calculators miss this — and miss queens.”
“Vet-call triggers per week are correct and well-prioritised. The Reality Check section is what I would say to an owner on the phone — comforting but clear.”
“Foster families are not breeders — they need a beginner-friendly visual. The dial pointer wins; everyone understands "we are HERE on the dial today".”
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