The name "millipede" comes from the Latin for "thousand feet," which is misleading. No commonly kept millipede species has a thousand legs. Most have somewhere between 100 and 400, depending on the species and the individual's age. But the real answer is more interesting than a single number.
It changes with every moult
Millipedes undergo anamorphic development, which means they add new body segments with each moult. More segments means more legs. A newly hatched millipede (called a pedeling) has very few segments and only a handful of leg pairs. With each successive moult, it gains more segments, and each new segment comes with its own two pairs of legs.
This is different from insects, which are born with their full complement of legs (six, always). A millipede's leg count is a moving target that increases throughout its life, slowing as it reaches maturity. So asking "how many legs does a millipede have?" without specifying the species and the animal's age is a bit like asking how tall a person is without specifying their age.
Typical counts for common species
Archispirostreptus gigas, the giant African millipede, typically has somewhere around 250-300 legs as an adult, though counts vary between individuals. Other large Spirostreptida species have similar numbers.
Smaller species tend to have fewer, but not always proportionally. The leg count depends on the number of body segments, which varies considerably between millipede families.
Flat-backed millipedes (order Polydesmida) are interesting because many species have a fixed number of segments as adults, usually 20 body segments (including the collum and telson), which gives them around 62 legs. That's a lot fewer than the giant round-bodied species, but they're still recognisably millipedes with their diplosegments and wave-like leg motion.
The actual record holder
In 2021, researchers described Eumillipes persephone, a species found deep underground in Western Australia. The specimen they studied had 1,306 legs across 330 segments, making it the first true millipede ever documented with more than a thousand legs. It's a threadlike, eyeless species adapted to subterranean life. You won't find it in any pet shop, but it did finally give the name "millipede" some legitimacy.
Before that discovery, the record was held by Illacme plenipes, a species from California with up to 750 legs. Still well short of a thousand, but impressive.
Why two pairs per segment?
The defining feature of millipedes (class Diplopoda) is the diplosegment: each visible body ring is actually two fused segments, each bearing a pair of legs. So each ring has two leg pairs. This is the key anatomical difference between millipedes and centipedes, which have one leg pair per segment.
The diplosegment arrangement allows millipedes to generate the pushing force they need to burrow through soil and leaf litter. All those legs work in coordinated metachronal waves, with each leg slightly out of phase with its neighbour. The result is a smooth, continuous forward push rather than the rapid, jerky movement of a centipede. It's a body plan built for pushing through substrate, not for chasing prey.
If you watch a millipede walking, you can see the wave pattern rippling along its underside. The legs on each side move in a sequence from back to front, creating a wave that travels down the body. It's hypnotic once you start watching it.
The first few legs are different
The very first body segment behind the head (the collum) has no legs. The next few segments have only one pair each rather than two. This is because the anterior segments haven't fused into diplosegments. Males also have modified legs on the seventh segment called gonopods, which are used for mating rather than walking. So even in a single animal, not every "leg" is doing the same job.
Does the count matter for keeping them?
Not really. There's no husbandry reason to count your millipede's legs. But understanding that the leg count increases with age matters because it tells you something about their biology. If you find a small millipede in your enclosure that's clearly a juvenile, you can expect it to gain segments and legs with each moult as it grows. It's a visible sign of development.
The main practical takeaway is that you can't use leg count to identify a species. A juvenile of a large species might have fewer legs than an adult of a small species. Species identification relies on body shape, colour, segment count in adults, the structure of the gonopods in males, and geographic origin.
So the answer to "how many legs does a millipede have?" is: it depends, it changes, and it's almost certainly not a thousand. But at least one species finally proved the name isn't completely wrong.