Female House Finch lacks the distinctive face pattern of the female Purple Finch. Cassin's Finch is very similar in all plumages but has streaked undertail coverts and a larger bill. Male Cassin's has a brighter red crown. Female Cassin's has finer streaking on the breast and a less noticeable face pattern. Pine Siskin is similar to female but smaller and lacks face pattern.
Sparrows are slimmer with longer tails and different markings.