No single clue dates a found kitten reliably, because nutrition, litter size and sheer individual variation all bend the timetable. Read as a sequence, though, her eyes, teeth, weight and walking usually narrow her age to a window of about a week in the first month of life — close enough to guide feeding and care until a vet examines her and confirms the estimate. Work through the clues in the order she developed them, and write down what you find while she is in front of you.
Eyes and Ears: The First Fortnight
She is born with her eyes sealed and her ears folded flat. Her eyes typically begin opening from around one week and are usually fully open by about two weeks, and all kittens start with blue eyes, so blue alone tells you she is young rather than giving you an exact week; her true eye colour develops later. Cloudiness, discharge or one eye staying shut is not an ageing clue but a reason for prompt veterinary care. Her ears unfold and start standing during roughly the third week, the same period her hearing becomes useful, so a kitten with pricked ears who turns toward sounds is unlikely to be under three weeks. A newborn also cannot regulate her own temperature well or toilet without her mother's stimulation, so a kitten who still needs help with either is very young indeed, and keeping her warm comes before every other assessment.
Teeth: The Most Readable Clock
Her baby teeth erupt in a dependable order, which makes her mouth the clearest guide you have. The small front teeth, the incisors, usually appear first from about two to three weeks. The pointed canine teeth follow at roughly three to four weeks. The cheek teeth, her premolars, come through across about four to six weeks, so a mouth with front teeth and canines but no cheek teeth yet points to roughly a month, while a full set of baby teeth suggests she is around six weeks or beyond. Look gently, without forcing her jaw, ideally while she yawns or nurses a finger-sized toy, and never use teeth alone: a well-grown three-week-old and a small four-week-old can look deceptively similar across a single feature, which is why the remaining clues matter.
Weight and Walking: The Cross-Checks
She typically weighs around 100 grams (about 3.5 ounces) at birth and gains roughly 100 grams (about 3.5 ounces) a week through the early weeks, so a kitten near 200 grams (about 7 ounces) is often around two weeks and one approaching 400 grams (about 14 ounces) is often near four weeks — hedged figures, since an underfed older kitten can weigh what a thriving younger one does. Weigh her daily at the same time on kitchen scales, because the direction of travel matters more than any single reading. Her movement completes the set: she crawls and paddles in week one, begins pushing up and wobbling on unsteady legs across weeks two to three, walks with improving steadiness during week four, and starts pouncing and running in short bursts as she moves toward five and six weeks. A kitten whose teeth suggest four weeks but who still only wobbles fits the range; one who runs confidently is telling you she is older than her size implies.
Confirming the Estimate and Acting on It
Treat the combined estimate as a working range and let a vet refine it promptly, checking her hydration, heart, temperature and any parasites at the same visit, because feeding frequency, warmth and weaning decisions all hang off her true age. If she is cold, limp, crying persistently or not feeding, skip the detective work and seek veterinary help urgently, since very young kittens deteriorate quickly. Once her age window is set, care becomes a rota of feeds, warmth checks and daily weights that several willing helpers can easily scramble, so putting the rota in writing protects her while everyone means well, and KinsLe protects it further as Care Teams lists every helper's assigned duties with completion times recorded beside each one.