Needed length of roller chain
Utilizing the center distance among the sprocket shafts as well as amount of teeth of each sprockets, the chain length (pitch quantity) can be obtained from the following formula:
Lp＝（N1 ＋ N2）/2＋ 2Cp＋｛（ N2－N1 ）／2π｝2
Lp : All round length of chain (Pitch amount)
N1 : Quantity of teeth of small sprocket
N2 : Amount of teeth of large sprocket
Cp: Center distance concerning two sprocket shafts (Chain pitch)
The Lp (pitch number) obtained through the over formula hardly becomes an integer, and typically incorporates a decimal fraction. 
Round up the decimal to an integer. Use an offset website link when the variety is odd, but select an even variety as much as probable.
When Lp is established, re-calculate the center distance among the driving shaft and driven shaft as described in the following paragraph. Should the sprocket center distance can’t be altered, tighten the chain using an idler or chain tightener .
Center distance concerning driving and driven shafts
Clearly, the center distance among the driving and driven shafts must be more compared to the sum with the radius of each sprockets, but normally, a right sprocket center distance is regarded as for being 30 to 50 instances the chain pitch. However, when the load is pulsating, 20 times or significantly less is correct. The take-up angle in between the modest sprocket and also the chain have to be 120°or far more. In case the roller chain length Lp is provided, the center distance between the sprockets can be obtained from your following formula:
Cp＝１/4Lp－(N1＋N2)/2+√(Lp－(N1＋N2)/2)^2－2/π2（N2－N1）^2
Cp : Sprocket center distance (pitch variety)
Lp : Overall length of chain (pitch variety)
N1 : Quantity of teeth of smaller sprocket
N2 : Quantity of teeth of huge sprocket