It's not cheap to leave an apartment in the middle of your lease. Most landlords will charge you some kind of lease breakage fee to help cover the cost of re-renting your unit. If you live in a building managed by a large property management firm, they probably have a fee in place that's between one and three months' rent. If you live in a rental unit managed by an individual person, then there's probably more room to negotiate—you might be able to get them to take one month of rent or less. Fees also vary by location. You will typically see higher termination fees in New York than in California, for instance.
Sometimes your landlord will use your security deposit to cover part of the fee, but not always. Many states have strict laws about what landlords can use security deposits to pay for, in which case your landlord should return your money after they've inspected the unit for damage.
The information provided on this website does not, and is not intended to, constitute legal advice.