The nominal fracture energy of concrete structures is constant for relatively large structures, whereas it increases with size for relatively small structures. If the energy dissipation space is modeled as a monofractal domain, with a non-integer dimension comprised between 2 and 3, a unique slope in the bilogarithmic fracture energy versus size diagram is found, as was stated in a previous paper [1]. On the other hand, when the scale range extends over more than one order of magnitude, a continuous transition from slope + 1/2 to zero slope may appear, according to the hypothesis of multifractality of the fracture surface [1]. This means that, at small scales, a Brownian microscopic disorder is prevalent whereas, at large scales, the effect of disorder vanishes, yielding a macroscopical homogeneous behavior. The dimensional transition from disorder to order may be synthesized by a Multifractal Scaling Law (MFSL) valid for toughness, in perfect correspondence with the MFSL valid for strength, which has been described in a previous paper [2]. The MFSL for fracture energy is applied, as a best-fitting method, to relevant experimental results in the literature, allowing for the extrapolation of fracture energy values valid for real-sized structures.