What Is RFM?
Recency
How recently a customer bought.
R=10-\frac{10}{\text{Recency Window}}\times \text{Months Since Last Invoice}
Frequency
How often a customer buys.
F=\min\!\big(\text{\# Invoices in Analysis Period},\,10\big)
Monetary
How much a customer spends.
M=\min\!\left(\frac{\text{Largest Invoice in Window}}{\text{Benchmark Value}}\times 10,\,10\right)
Overall RFM
Final Average Calculation
\text{RFM Score}=\frac{R+F+M}{3}