How Old Was Jacob When Isaac Died?

Jacob was 120 years old when Isaac died. Isaac lived 180 years, and he was 60 when Jacob and Esau were born, so Jacob’s age at Isaac’s death is 180 − 60 = 120.

The calculation from two clear ages

Genesis 25:26 says Isaac was threescore years old when Rebekah bare Jacob and Esau. Genesis 35:28–29 says the days of Isaac were an hundred and fourscore years, and he gave up the ghost and died.

Subtracting Isaac’s age at the twins’ birth from his age at death yields Jacob’s age at the funeral: 180 − 60 = 120. Esau was the same age, and the brothers buried their father together.

Where this sits in Jacob’s life

On the wider chronology Joseph had already been sold when Jacob was about 108, so Isaac’s death about twelve years later falls while Joseph is in Egypt and Jacob still believes Joseph is dead. Ten years after Isaac’s death Jacob enters Egypt at 130.

Isaac’s death is therefore a firm mathematical point rather than an estimated service year. It helps confirm the structure of Jacob’s later life.