The male House Finch can be told from Cassin's and Purple Finches by its streaked belly, browner back and nape, longer unforked tail and different call notes. Female House Finches have much plainer faces than the other finches. Pine Siskins are smaller with yellow patches in the wings and tail. Sparrows typically have more distinctive face patterns.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.