Some people wonder how many days the stock market is open in the United States. This is a very useful number because many of the online day traders want to calculate how much money they need to make per day, to replace their current salary.

The numbers below represent standard stock market hours in 2009 which usually span from 9:30 to 16:00 Eastern Standard Time.

Some futures markets will trade up to 16:15 Eastern Standard time.

The markets are usually open for the normal trading session Monday Through Friday.

I have not included after hours trading, pre market trading, currency (FOREX) markets, international markets or GLOBEX.

So lets take a look at the number of trading days in 2009 by month:

January: 20 days

February: 19 Days

March: 22 Days

April: 21 Days

May: 20 Days

June: 22 Days

July: 22 Days

August: 21 Days

September: 21 Days

October: 22 Days

November: 19.5 Days (The 0.5 is because Nov. 27,2009 is a half day for the market)

December: 21.5 Days (The 0.5 is because Dec. 24,2009 is a half day for the market)

This brings the total number of trading days in 2009 to: 251 trading days in 2009.

So if you wanted to replace a salary of $100,000 per year before taxes, we could need to do the following math:

$100,000 divided by 251 trading days equals $398.41 dollars per day.

The trader would then need to have an average net profit of $398.41 dollars per day in 2009 (after commissions, software, data services, taxes and other overhead is factored into the picture.)

Many traders do not trade every single day for a wide variety of reasons, but at least you know the maximum numbers of days you could possible trade in 2009