Number Pooling
US (established); Canada (phasing in by exchange, 2026–2027) · also called thousands-block pooling
Allocating numbers in 1,000-blocks instead of whole NXX codes, so capacity is shared and conserved.
Number pooling (thousands-block number pooling) is the practice of allocating telephone numbers to carriers in blocks of 1,000 (thousands-blocks) rather than in whole 10,000-number NXX codes. Unused blocks return to a shared pool administered by the Pooling Administrator, dramatically slowing area-code exhaust.
Pooling has long been used in the US in most rate centers. Canada is now phasing thousands-block pooling in on an exchange-by-exchange basis under a CRTC decision — the first exchanges convert by 28 July 2026 and the final exchanges by 28 July 2027 — so whether a given Canadian rate center pools depends on where it is in that schedule; check the Canadian Numbering Administrator for current status. Pooling is the reason a single NXX can be shared among several carriers.
Pooling did not "fix" number shortages permanently; it slowed exhaust. Codes still fill up, just more slowly, and relief is still needed.