In summary: constexpr variables are constant and usable in constant expressions constinit variables are not constant and cannot be used in constant ex

In summary: constexpr variables are constant and usable in constant expressions constinit variables are not constant and cannot be used in constant expressions constexpr can be applied on local automatic variables; this is not possible with constinit, which can only work on static or thread_local objects you can have a constexpr function, but it’s not possible to have a constinit function declaration