What is a calling range in poker?

A calling range is the hands a player continues with against another player's raise or shove, rather than folding - at push/fold depths, that usually means calling all-in.

A calling range is generally wider than an opening range from the same seat would be, since a caller only has to beat the one range the opener actually shoved, not the whole field left to act. It also depends heavily on who opened: the calling range against a tight opener is much narrower than the calling range against a loose one, even from the identical seat and stack depth.

The mechanism is pot odds. Calling a 10bb shove from the big blind means putting in 9bb more to win a pot of roughly 21.5bb, so the call needs about 42% equity to break even on chips alone. That threshold is what decides the boundary of the range, and it moves with the shove size: against a 6bb shove the big blind is getting a much better price and can defend far wider, while against a 20bb shove it needs a genuinely strong hand.

Which hands clear that threshold is less intuitive than it looks. A hand like K9o has real equity against a wide shoving range but is dominated by a large slice of the hands that shove tight, so it swings from a clear call to a clear fold depending only on who is pushing. Small pairs behave the opposite way - they are close to a coinflip against almost everything, which makes them stable calls across a very wide band of opponent ranges.

Tournament payouts move the boundary again, and always in the same direction. Once busting costs more than doubling gains, the equity a call needs rises above the raw pot-odds number, and hands sitting near the edge drop out of the range first. That gap is what risk premium and bubble factor measure, and it is why an ICM-aware calling range near the money is visibly tighter than the chip-EV one from the identical seat.