I breed Golden Retrievers, so read this knowing that. I am going to try to be straight with you anyway, because a family that wanted a Labrador and ended up with a Golden is not a good outcome for anyone, least of all the dog.
They are close relatives and they overlap heavily. Both were bred to retrieve shot game, work with a handler all day and carry something soft in their mouth without damaging it. That shared job is why both are biddable, food-motivated, people-focused and generally excellent with children. If you are choosing between them, you have already narrowed it to two very good answers.
Coat and grooming, the real difference
This is the one that actually changes your daily life.
A Labrador has a short, dense double coat. It sheds constantly, the hair is short and bristly and gets into everything, and grooming is a brush and not much else.
A Golden has a longer double coat with feathering on the legs, chest, tail and ears. It sheds heavily too, in longer strands that clump rather than embed. It needs brushing two or three times a week, more when it blows its coat, and the feathering picks up mud, burrs and pond water enthusiastically.
Neither is low-maintenance. If somebody tells you either of these breeds does not shed much, they have not lived with one. The honest framing is: the Labrador is less work to groom, the Golden is less work to vacuum.
Energy and intensity
Broadly, Labradors run a little hotter and stay boisterous a little longer. Goldens tend to mature slightly earlier and sit a fraction softer. Both are adolescent lunatics from about eight months to two years and anyone who tells you otherwise is remembering it fondly rather than accurately.
The variation within each breed is far larger than the difference between them. A calm Labrador from calm parents will be calmer than a busy Golden from busy parents, every time. That is why I keep telling people to look at the actual parents rather than the breed page.
Temperament
Labradors are often described as more independent and a bit more robust. Goldens are often described as more sensitive and more emotionally attentive, which is a genuine tendency and cuts both ways. A Golden will notice you have had a bad day and come and sit with you. A Golden will also take a harsh telling off harder than it needs to, and a heavy-handed household gets less out of one.
If you want a dog that is a bit thicker-skinned and gets on with things, the Labrador has a slight edge. If you want a dog that is tuned in to the household’s mood, the Golden does.
Health
Both are prone to hip and elbow dysplasia and both are prone to putting on weight, which makes the joints worse. Goldens have a higher cancer rate than most breeds, and that is a real and well-documented difference worth knowing before you choose. Labradors have their own genetic issues and a famous appetite that will get them fat if you let it.
For both, the two things that most affect how long the dog stays sound are entirely in your hands: keep it lean, and do not over-exercise it while the growth plates are still open.
Size and colour
Similar sizes, with Goldens often looking bigger because of the coat. Labradors come in black, yellow and chocolate. Goldens come in one pigment expressed from cream through to deep red, which the colour guide goes into properly.
So which one
Choose the Labrador if grooming time is genuinely scarce, if you want a slightly more robust dog, or if your household is loud and busy in a way that a sensitive dog might find wearing.
Choose the Golden if you want the softer, more emotionally attentive version, if you do not mind the coat, and if the people in the house will enjoy a dog that follows them from room to room.
And if you are still genuinely torn, that is a good sign rather than a bad one. Go and meet the actual parents of an actual litter of each. You will know within ten minutes, and it will have nothing to do with the breed and everything to do with those particular dogs.