While there is no need for special language on IRA hardship withdrawal limits, due to the ability to take your money out at any time, 401(k) plans are a different story. 401(k) plans, and similar qualified plans such as the 403(b) and 457(b), are more restrictive than IRAs; they are easier to fund (because they're funded with after-tax dollars) but you generally cannot touch any of the money until retirement. However, such a plan is permitted (but not required) to provide for hardship distributions. The rest of this article will assume a 401(k), but the rules for the other qualified plans are similar.
A hardship distribution must be made due to an immediate and heavy financial need, and must be sufficient to satisfy the need. (The need can be of the account owner directly or of the owner's spouse or children). A need does not have to be unforeseen to be immediate and heavy. Examples of legitimate expenses include medical expenses, buying a (primary) home, educational posts, avoiding eviction from your primary home, funeral and burial expenses, and repairing damage to your primary home. Such a distribution may only be made if no other resources are available to meet the need.
There is no fixed dollar limit of how much you can withdraw from your plan; however, it cannot be more than is required to meet the hardship need or more than the total amount of contributions (not earnings or matching contributions from your employer) made to the plan.