Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

BLACKROCK FUNDS

Prospectus Date

rr_ProspectusDate

Nov. 28, 2016

Supplement [Text Block]

bf15_SupplementTextBlock

BLACKROCK FUNDS^SM

BlackRock Midcap Index Fund

(the “Fund”)

Supplement dated April 5, 2017

to the Fund’s Summary Prospectus, Prospectus

and Statement of Additional Information (“SAI”), each dated November 28, 2016

Effective June 19, 2017, the Fund will change its name to iShares Russell Mid-Cap Index Fund. Accordingly, effective June 19, 2017, references to the Fund’s name in the Fund’s Summary Prospectus, Prospectus and SAI are changed to reflect the new Fund name.

BlackRock Midcap Index Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

bf15_SupplementTextBlock

BLACKROCK FUNDS^SM

BlackRock Midcap Index Fund

(the “Fund”)

Supplement dated April 5, 2017

to the Fund’s Summary Prospectus, Prospectus

and Statement of Additional Information (“SAI”), each dated November 28, 2016

Effective June 19, 2017, the Fund will change its name to iShares Russell Mid-Cap Index Fund. Accordingly, effective June 19, 2017, references to the Fund’s name in the Fund’s Summary Prospectus, Prospectus and SAI are changed to reflect the new Fund name.