According to this process for manufacturing a laminated glazing unit so that it withstands predetermined stresses, a reference laminated glazing unit is identified that withstands the predetermined stresses and that comprises at least one substrate and one interlayer having the same chemical compositions as those of the laminated glazing unit to be manufactured; the tear strength (Jc-ref) of the interlayer of the reference laminated glazing unit, and also the interlayer thickness (ei-ref) and the substrate thickness (eg-ref) of the reference laminated glazing unit are then determined; then, using a graph (C4) representative of the minimum interlayer tear strength (Jc-min) required so that any laminated glazing unit, comprising at least one substrate and one interlayer having the same chemical compositions as those of the laminated glazing unit to be manufactured, withstands the predetermined stresses, as a function of the interlayer thickness (ei) and/or of the substrate thickness (eg), a combination of optimum values (ei-opt, eg-opt) of the interlayer thickness and of the substrate thickness is deduced; the laminated glazing unit is then sized with an interlayer thickness (ei-dim) and a substrate thickness (eg-dim) that are greater than or equal to the optimum values (ei-opt, eg-opt).