Pips, points and lots
Pips measure price moves. Lots measure position size. Together they set what each move is worth.
Pips
For most pairs a pip is the fourth decimal (0.0001). For yen pairs it's the second (0.01). Many brokers quote one more digit, called a pipette or point.
Lots
A standard lot is 100,000 units of the base currency. A mini lot is 10,000 and a micro lot 1,000. Gold is usually 100 ounces per lot, but contract sizes vary by broker: check the spec sheet.
Pip value
On EUR/USD, one standard lot moves about $10 per pip, a mini lot $1 and a micro lot $0.10. On pairs where the dollar isn't the quote currency, the value changes with the exchange rate.
Use the calculator
The trade calculators work out pip value and position size for any pair and account currency.