The following formula can be used to determine the monthly cost of a long-distance plan based on your specific calling habits.
Cost = [(X1*R1) * (1+ U)] + (X2*R2) + (X3*R3) + F + I
Where,
X1 = Number of State-to-State minutes per month.
X2 = Number of InterLATA minutes per month.
X3 = Number of IntraLATA minutes per month.
R1 = State-to-State rate per minute.
R2 = InterLATA rate per minute.
R3 = IntraLATA rate per minute.
F = Monthly Fee
U = Universal Service Fund Fee
I = In-State Connection Fee
For Example, the monthly cost for an Average Volume User (120 minutes per month with 50% State-to-State, 25% InterLATA, and 25% IntraLATA) for a C-COM customer (excluding taxes) would be calculated as follows:
Cost = [(X1*R1) * (1+ U)] + (X2*R2) + (X3*R3) + F + I
Cost = [(60 * $0.079) * (1 + 0.0667)] + (30 * $0.089) + (30 * $0.089)
Cost = $10.40
Keep in mind that some calling plans have minimum charges that may apply if your actual call volumes are too low.