What a one-pip move is worth on your position, in the currency your account is actually denominated in.
Every other calculation on this site needs this number first. Position size needs it, risk per trade needs it, and the cost calculators need it.
It is not a fixed $10. It depends on the pair, the size, and what currency your account is held in, and yen pairs use a different pip size entirely, which is the most common way a position ends up sized ten times wrong.
A model, not a quote. Every figure here comes from what a broker publishes or what you type, and real fills, spreads and rates move.
One standard lot of EUR/USD in a dollar account: 100,000 units × 0.0001 = $10 a pip. Straightforward, and where the familiar $10 comes from.
One standard lot of USD/JPY at 150: 100,000 × 0.01 = ¥1,000 a pip, which at 150 to the dollar is about $6.67.
Same lot size, two-thirds the risk per pip. A stop measured in pips therefore means something different on each, which is why position size has to be worked out per pair rather than assumed.
Most platforms quote a fifth decimal place on non-yen pairs and a third on yen pairs. That last digit is a tenth of a pip, not a pip.
A spread displayed as 12 on a five-decimal feed is 1.2 pips. Reading it as 12 pips overstates your costs tenfold and will make every broker look unaffordable.
Only for a pair quoted in your account currency, at one standard lot. Change the pair, the size or the account currency and it changes.
A tenth of a pip: the extra decimal place most brokers now quote. Useful for pricing precision, and a reliable source of confusion when reading spreads.
Because the exchange rate runs in the hundreds rather than near one. A pip is meant to be a small but meaningful move, and on a rate of 150 the fourth decimal place is not one.
For pairs quoted in your account currency, no. Where a conversion is involved it drifts slightly with the conversion rate, which matters over a long hold and not within a trade.