Pick the parents' eye colors (and grandparents', for a sharper estimate) to see the likely odds for your baby or child's eye color.
Pick both parents' eye colors above (and grandparents', if you know them, for a sharper estimate) to see rough odds for brown, hazel/green and blue/gray. Eye color is influenced by several genes working together, so this is a simplified estimate rather than a certainty — two brown-eyed parents can still have a blue-eyed baby, and vice versa.
Many babies are born with a grayish-blue or indeterminate eye color that shifts as melanin builds up over their first several months — most eye color is fairly settled by around 6–9 months, though some continue to shift subtly until closer to their first birthday.
It's uncommon but not impossible — eye color depends on multiple genes, not a single simple trait, so unusual combinations can occasionally appear even when both parents share the same eye color. It's far more likely with brown, since brown is generally dominant over blue.
Not this one — hair color depends on a different, even more complex set of genes than eye color, so we don't estimate it here. As a rough guide, darker hair tends to be genetically dominant over lighter shades, but the actual outcome for any specific baby is much harder to predict reliably.
Yes — the genetics don't change after birth, so the same odds apply whether you're estimating for a newborn or an older child. Just keep in mind that eye color can keep shifting for the first several months to a year of life, so a very young baby's current eye color isn't necessarily their final one.