A standard forex account has specific lots and pip units. A lot is the minimum quantity of a security that may be traded, while a pip is the smallest amount by which a currency quote can change. Typically, one lot is worth $100,000 and a pip unit is stated in the amount of $0.0001 for U.S.-dollar related currency pairs. This is the most common pip unit and it is used for almost all currency pairs. Pip value is the effect that a one-pip change has on a dollar amount. It is important to note that pip value does not vary based on the amount of leverage used, but rather that the amount of leverage you have affects the pip value.
Leverage is the amount of money you are able to spend as a result of borrowing investment capital. Basically, the more leveraged you are, the riskier your position—a decrease of a few pips could mean losing all of the money in your account. For example, with a standard lot size of $100,000, pip value is $10 ($100,000 x 0.0001). If your account contains $10,000 and you have a leverage of 150:1, then you will have $1.5 million ($10,000 x 150) or 15 lots ($15,000,000/$100,000) that you can use for investing. It would be extremely risky to use the entire $1.5 million that you have available because each pip is worth $150 and you could clean out your account just by losing 67 pips ($10,000/150). Although there is large downside risk to having high leverage, there is also a large upside gain—if you were to make 67 pips instead, your account value would double, and you would rake in 100% returns in one day!
Increasing your leverage increases the volatility of your position because small changes in pip value will result in larger fluctuations in your account value. (See also: Getting Started in Forex, A Primer on the Forex Market, Common Questions About Currency Trading and Using Currency Correlations to Your Advantage.)