Muna Abdirazak, aged 21 months, suffered severe head injuries when she plunged from the third floor of the building in Bristol.
Avon Coroner's Court heard Muna climbed out of bed in the early hours of the morning on July 15, 2013 and pushed open the kitchen door. She is believed to have clambered on to a wooden chair and then on to the kitchen table - before toppling out of the open window next to it.
Muna's horrified parents, Layla Mohamed and Abdi Abdirazak, woke to find their daughter missing from the two-bedroom home in Polden House, Windmill Hill.
They spotted the window open at a 45-degree angle and ran downstairs to find Muna receiving treatment from paramedics.
Muna was rushed to Bristol Royal Hospital for Children, where she was pronounced dead a short time later. Avon Coroner Maria Voisin returned a verdict of of accidental death at the inquest.