DLS means diagonal leg span
The common hobby measurement runs from the tip of one front leg diagonally across the body to the opposite rear leg with the spider in a normal spread position.
It is approximate
A living tarantula changes posture constantly, so DLS is not a millimetre-precise measurement. Shop listings and care guides use it as a practical size estimate.
Body length is different
Body length excludes the legs and produces much smaller numbers. Always check which measurement a seller is using.
Why DLS helps
DLS is useful for enclosure sizing, prey selection and comparing the adult size of species.
Do not stretch the spider
Never handle or physically extend the legs to measure a tarantula. Estimate through the enclosure or use a moult when practical.
Growth records
Recording approximate DLS after moults can show growth over time, but the moult date and life stage are usually more useful than chasing exact centimetres.