How to determine the ATM_strike and ATM_vol?

[tyskland]

How do I determine the ATM_strike and ATM_vol if I have the following information?

Spot price = 100
Strike prices = [100 120 140 160 180 200]
Market implicit volatilities = [18.7 16.9 12.8 11.9 10.1 9.7]/100
T = time to maturity = 0.185

If I plot the volatility smile (i.e. plotting strike prices against impl_vol), is the ATM_strke and ATM_vol the minimum point on this smile?

 

[latency]

typically, traders use what is called the At the money forward. Just compute the forward price of the underlying and the strike closest to this forward price is the ATM. the point with the lowest vol is not necessarily the atm.

 

[tyskland]

typically, traders use what is called the At the money forward. Just compute the forward price of the underlying and the strike closest to this forward price is the ATM. the point with the lowest vol is not necessarily the atm.

Thanks that is reasonable.