In the title mol-ecule, C11H10O3, the fused dihydro-pyran ring is in a half-chair conformation with the O atom and the methyl-ene C atom positioned 0.1318 (13) and 0.143 (2) Å, respectively, on either side of the mean plane formed by the other four atoms. In the crystal, weak C-H⋯O hydrogen bonds link mol-ecules along [001].