Purpose: This study aims to conduct a comprehensive life cycle assessment (LCA) of wood-based boards to support environmentally conscious design. The goal is achieved by the following objectives: to produce generic LCA data for production of wood-based boards (cradle-to-gate) and to evaluate the human health impacts through life cycle including the use stage (cradle-to-grave), based on the latest regulations for formaldehyde emissions in Japan. Methods: Production data of particleboard (PB), hard fiberboard (HB), medium-density fiberboard (MDF), and insulation fiberboard (IB) were obtained from major manufacturers of wood-based boards in Japan. We evaluated the impact categories of climate change, abiotic resource depletion, human toxicity (cancer and non-cancer effects), and ecotoxicity (cradle-to-grate assessment). For the human health impacts by formaldehyde emissions from PB and MDF in the use stage (40 years), we calculated the impacts through the life cycle (cradle-to-grave assessment), at all grades of formaldehyde emission rates set by the formaldehyde regulation. Results and discussion: Cradle-to-gate assessment indicated that adhesives constituted 28–55% of the impacts in all categories for PB and MDF, whereas 74–98% of the impacts resulted from utilities supply for HB and IB. In particular, heat supply from wood boilers accounted for more than 92% of human health (non-cancer) and 71% of ecotoxicity impacts in HB. Cradle-to-grave assessment of PB and MDF, which satisfy strict regulations on formaldehyde emissions (&lt
0.005 mg/m2/h), demonstrated that impacts on human health (total of cancer and non-cancer effects) were decreased by more than 90% compared with a conventional product (0.15 mg/m2/h). The production stage impacts of the products meeting the string regulations were more than half of the total owing to the lower formaldehyde emissions in the use stage. Conclusions: Generic LCA data for wood-based board production (cradle-to-gate) in Japan are calculated. Significant impacts are adhesives for PB and MDF and utility supply for HB and IB. The cradle-to-grave assessment of PB and MDF revealed that shifting to low-formaldehyde emission products has markedly reduced impacts on human health. We recommend preferentially improving the environmental performance of the production process of wood-based boards in countries with strict regulations on formaldehyde emissions.