Lot size and pair in. The dollar value of a single pip move out.
This assumes the quote currency is USD and uses a standard pip definition (0.0001, or 0.01 for JPY pairs). Actual pip value varies by the specific pair and current exchange rate, always confirm with your broker's own calculator before sizing a live position.
A standard lot moving 20 pips can mean a meaningfully different dollar swing than the same trade in a mini or micro lot. Forex's leverage means position sizing mistakes compound faster here than in most other instruments, knowing your exact pip value before entry is part of knowing your real risk, not just an afterthought.