In general, yes, you will owe tax on the increase. For property held for less than one year, that is a short term capital gain which is taxed as ordinary income at whatever your ordinary tax rate is. Buying another home will have no effect. The ability to defer gain by buying another home was removed from the tax code in the late 1990s. Since then, when you sell a home you must determine gain or loss and pay tax on the profit. There is no way around that. If you sold your home because of a job change or "unforeseen circumstances" you might be able to exclude some of the gain. See IRS Publication 17 for the details on that.
http://www.irs.gov/pub/irs-pdf/p17.pdf
In general, yes, you will owe tax on the increase. For property held for less than one year, that is a short term capital gain which is taxed as ordinary income at whatever your ordinary tax rate is. Buying another home will have no effect. The ability to defer gain by buying another home was removed from the tax code in the late 1990s. Since then, when you sell a home you must determine gain or loss and pay tax on the profit. There is no way around that. If you sold your home because of a job change or "unforeseen circumstances" you might be able to exclude some of the gain. See IRS Publication 17 for the details on that.
http://www.irs.gov/pub/irs-pdf/p17.pdf