How to Use FOIL Calculator
The FOIL Calculator expands two binomials. Enter an expression such as (x + 3)(x + 5), then the FOIL Calculator shows the final polynomial and the four FOIL parts.
Because the steps are separated, the FOIL Calculator is useful for learning why the middle coefficient appears after the outer and inner products are combined.
Formula & Theory — FOIL Calculator
The FOIL Calculator uses (a + b)(c + d) = ac + ad + bc + bd. The first product is ac, the outer product is ad, the inner product is bc, and the last product is bd.
After the four products are made, like terms are combined. The FOIL Calculator gives both the step pieces and the simplified result.
Use Cases for FOIL Calculator
Use the FOIL Calculator for algebra homework, binomial multiplication practice, quadratic expression checks, factoring verification, and classroom examples. The FOIL Calculator is best for two-binomial products where seeing each part matters.