@ arkhe:
The swap value for buy positions and sell positions depends on the currency pair, as interest rates vary from country to country.
The calculation method:
For currency pair A/B:
Buy position, swap = ((interest rate of country A - interest rate of country B) x lot x contract size)) / 365 days
Sell position, swap = ((interest rate of country B - interest rate of country A) x lot x contract size)) / 365 days
Here are the swaps as of November 27, 2015 from one broker:
EUR/USD : swap for buy : -USD 3.60 ; swap for sell : +USD 1.15
AUD/USD : swap for buy : +USD 4.15 ; swap for sell : -USD 7.06
USD/CHF : swap for buy : +2.39 ; swap for sell : -USD 7.86
US interest rate : +0.25%, Eurozone interest rate : +0.05, Australian interest rate : +2.0% and Swiss interest rate : -0.75%.
For swaps, each broker is different but not significantly so.