Red-eared sliders typically live 15–30 years (PetMD), with reports of 30–40 in captivity (RSPCA) and up to 30 in the wild. A 5-year-old male is usually 3.8–6 in long and a 5-year-old female 6.1–6.4 in. A 10-year-old slider is about 32.5 in human years.
Estimates only. Tortoises and turtles age at very different speeds by species and care. See a reptile vet for health concerns.
Red-eared slider lifespan: how long do sliders live?
The red-eared slider lifespan surprises many owners who bought a coin-sized hatchling. PetMD's vet-reviewed lifespan table gives 15–30 years, and its species profile says sliders can enjoy "a lifespan of well over twenty years". The RSPCA says terrapins have been reported living around 30 to 40 years in captivity. The oldest slider in the AnAge longevity database lived 41.3 years in captivity. The calculator uses PetMD's 15–30 years as the typical range and flags older turtles as beyond typical.
Enter your slider's age and sex above to see its age in human years, its life stage, how much of a typical lifespan it has used and the shell length expected for its age. Females grow noticeably larger than males, so choosing the sex narrows the size range.
Slider turtle lifespan in captivity vs the wild
AnAge notes that in the wild "these animals live up to 30 years", and that field studies found no increase in mortality with age. Oregon Sea Grant's species guide says sliders can live more than 20 years and up to 30. In captivity the upper end depends heavily on care. PetMD notes that pets generally outlive wild turtles because they avoid predators and get veterinary care, but only when their water, heat, light and diet are right.
| Slider age | Human years | Life stage |
|---|---|---|
| 10 years | 32.5 | Adult |
| 15 years | 48.7 | Adult |
| 20 years | 65 | Senior |
| 25 years | 81.2 | Senior |
| 30 years | 97.5 | Senior |
| 35 years | 113.7 | Senior (beyond typical) |
| 40 years | 130 | Senior (beyond typical) |
Red-eared slider age and size chart
This chart shows the typical shell (carapace) length of male and female red-eared sliders by age. It is based on a 37-year study in Indiana and an earlier study in Texas, compiled by Lewis et al. (2018) in Herpetological Conservation and Biology. Each range spans the two populations. Hatchlings emerge at about 1.1 inches (27.65 mm). Growth slows sharply after about 9 years, so the chart stops there.
| Age | Male shell length | Female shell length | Human years | Life stage |
|---|---|---|---|---|
| At hatching | 1.1 in | 1.1 in | — | Hatchling |
| 1 year | 1.8–2.6 in | 2.6 in | 3.2 | Juvenile |
| 2 years | 2.4–3.8 in | 3.7–3.8 in | 6.5 | Juvenile |
| 3 years | 2.9–4.7 in | 4.7–4.9 in | 9.7 | Juvenile |
| 4 years | 3.4–5.4 in | 5.5–5.7 in | 13 | Juvenile |
| 5 years | 3.8–6 in | 6.1–6.4 in | 16.2 | Adult |
| 6 years | 4.2–6.5 in | 6.7–7 in | 19.5 | Adult |
| 7 years | 4.6–6.8 in | 7.2–7.5 in | 22.7 | Adult |
| 8 years | 4.9–7.1 in | 7.6–7.9 in | 26 | Adult |
| 9 years | 5.2–7.3 in | 7.9–8.2 in | 29.2 | Adult |
Converted from plastron (bottom shell) length with the paper's plastron-to-carapace ratios. Wild turtles from colder or less productive habitats grow more slowly, and well-fed captive turtles may grow faster.
Male vs female size
Lewis et al. found that female growth pulls away from males' by about the fourth year of life. Across the populations they compiled, adult males averaged about 135–184 mm (5.3–7.2 in) of shell length and females about 189–228 mm (7.4–9 in). The RSPCA gives roughly 21 cm for males and 25 cm for females in captivity. On our chart a 3-year-old male is about 2.9–4.7 in and a 3-year-old female 4.7–4.9 in. At 9 years, males are 5.2–7.3 in and females 7.9–8.2 in. Males also mature earlier: 2–6 years vs 4–9 for females in normal habitats (Lewis et al. 2018, Table 4). Adult males have longer front claws and thicker tails (Oregon Sea Grant).
Terrapin or turtle? The UK vs US names
It's the same animal. In the United States, Trachemys scripta elegans is usually called the red-eared slider or slider turtle. In the UK and Ireland, freshwater turtles like this are commonly called terrapins. The RSPCA's care page is titled "How to care for a terrapin", and the UK's National Wildlife Crime Unit lists the species as "Terrapin (also known as Sliders)". So the red-eared terrapin lifespan is the same as the red-eared slider lifespan: typically 15–30 years, with reports of 30–40 in captivity.
What shortens or extends a slider's life?
- Water quality: sliders eat, drink and defecate in their water. The RSPCA recommends a filter plus weekly 20% water changes, dechlorinated water and test kits for ammonia and nitrite. It suggests about 400 litres of water for a 25 cm terrapin.
- Basking and UVB: sliders need a dry basking spot where they can completely dry off, plus UVB lighting. PetMD says to "make sure to get bulbs that produce UVB", and the RSPCA recommends a UV index of 3–5 in the basking zone, falling to zero in the shade.
- Diet: sliders are omnivores. PetMD recommends a varied diet of vegetables, insects and worms, feeding young sliders daily but adults only every 2–3 days to prevent obesity. Poor diets cause calcium and vitamin deficiencies.
- Space: PetMD suggests at least a 20-gallon tank for one turtle, with dimensions at least 4–5 times the turtle's length. A growing female soon needs far more.
- Veterinary care: PetMD lists vitamin A and calcium deficiencies, abscesses, parasites, infections and shell damage among the problems that shorten turtle lives.
Common health issues
The problems vets see most often in sliders are mostly linked to husbandry (general information only):
- Metabolic bone disease (MBD): caused by low calcium or vitamin D3, often from missing UVB. The RSPCA lists swellings around the mouth or eyes and an uneven shell as signs.
- Eye problems and mouth rot: both named by the RSPCA as common in terrapins.
- Respiratory infections and parasites: listed by PetMD for red-eared sliders.
Swollen eyes, a soft or misshapen shell, swimming lopsided, breathing with an open mouth or refusing food all deserve a prompt visit to a reptile vet.
Never release a slider
Because they live so long and grow so large, sliders are often released into ponds when owners can no longer keep them. That is harmful and, in many places, illegal. The US Geological Survey says released pets now live in many non-native areas, where they compete with native turtles for food and basking sites. Oregon Sea Grant notes that the red-eared slider is on the Global Invasive Species Database's list of the "100 of the World's Worst Invasive Alien Species". It is illegal to release turtles in Oregon, and since 1975 it has been illegal in the US to sell turtles with shells under 4 inches. In the EU the species has been on the list of invasive alien species of Union concern since 2016. In the UK, the Invasive Alien Species Order 2019 means you must not release, breed or sell a terrapin without a licence (National Wildlife Crime Unit). If you can't keep your slider, contact a reptile rescue.
How the slider calculator works
Human years are scaled to PetMD's typical 15–30 year lifespan against the WHO human life expectancy of 73.1 years, so each slider year counts as about 3.2 human years. Life stages use the maturity ages above: about 4 years for males, 6 for females and 5 if you're not sure. Senior starts at 75% of the typical lifespan. The expected shell length comes from the age and size chart. Compare sliders with other species in our turtle and tortoise lifespan by species guide, or use the tortoise and turtle age calculator for box turtles, painted turtles and more.
Frequently asked questions
What is the red eared slider lifespan?
Typically 15–30 years according to PetMD, and often well over 20. The RSPCA reports 30–40 years in captivity, and the oldest recorded lived 41.3 years (AnAge).
What is the red eared terrapin lifespan?
The same as the red-eared slider's, because 'terrapin' is the usual UK name for the same species. The RSPCA says terrapins have been reported living around 30–40 years in captivity.
What is the red slider turtle lifespan in the wild?
AnAge's longevity database says wild sliders live up to 30 years, and field studies found no increase in mortality with age. Oregon Sea Grant says sliders can live more than 20 years.
What is the slider turtle life expectancy as a pet?
About 15–30 years with good care (PetMD). Clean, filtered water, UVB lighting, a basking spot and a varied diet help sliders reach the upper end.
How big is a 3 year old red eared slider?
Typically 2.9–4.7 in for a male and 4.7–4.9 in for a female (Lewis et al. 2018).
How big is a 5 year old red eared slider?
Typically 3.8–6 in for a male and 6.1–6.4 in for a female.
How old is a 10 year old red eared slider in human years?
About 32.5 human years, scaled to a 15–30 year lifespan.
How old is a 20 year old red eared slider in human years?
About 65 human years, which is in the senior stage.
Do male or female red eared sliders get bigger?
Females. Their growth pulls ahead by about the fourth year, and adult females averaged about 189–228 mm of shell length across populations versus 135–184 mm for males (Lewis et al. 2018).
Can I release my red eared slider into a pond?
No. Sliders are invasive in many regions and harm native turtles. Releasing them is illegal in many places, including Oregon, the EU and the UK. Contact a reptile rescue instead.
This calculator gives an estimate for education and fun. Every pet ages differently — for health decisions, talk to your veterinarian.