Cradle-to-gate vs cradle-to-grave

A carbon figure is only meaningful with its system boundary — the slice of the life cycle it covers. Mixing boundaries is one of the most common ways material comparisons go wrong.

The three you will meet

Cradle-to-gate covers raw-material extraction, transport and manufacturing up to the factory gate. In EN 15804 (the European construction-products standard) this is modules A1–A3. Most of MatQuo's verified factors — polymers, steel products, primary aluminium, flat glass — are cradle-to-gate. Cradle-to-grave adds distribution, use and end-of-life (modules A4–C). Cradle-to-cradle goes further and folds the recycling loop back in; MatQuo's container-glass number (FEVE) is on this basis, which is exactly why it cannot be lined up against a cradle-to-gate polymer number.

Why it matters

A cradle-to-cradle number already contains a recycling benefit that a cradle-to-gate number does not. Put them side by side and the cradle-to-cradle material looks unfairly good. That is not a real difference in the material — it is a difference in what was counted. MatQuo's tools check the boundary before comparing and block pairs that do not match.

And Module D

EN 15804 also defines Module D — benefits and loads beyond the system boundary, such as an end-of-life recycling credit. It is reported separately and must not be subtracted from A1–A3. See what Module D means in steel EPDs.