I just turned 62 (Dec 2018), but plan to wait until FRA of 66 & 4 months to claim. My projected benefit will be $2866 per month. At that time my wife will just turn 63 and we plan to have her take a spousal benefit of $1433 as that would be larger than her FRA projected benefit 4 years later. We also have an adopted minor child who at that time could get a benefit for another two years. After reading Get What's Yours- Social Security, it sound like our full family benefit would be 1.8 times my FRA benefit ( $5158.80 ), is that correct or will the family limit be lower? Also after reading the book it sounds like for my daughter to get a benefit, I have to be collecting a benefit?
Family maximum benefits (FMB) normally can't exceed 175% of the worker's primary insurance amount (PIA). So, if your PIA is $2866 your FMB would likely be roughly $5015. If your wife files for spousal benefits at age 63, she'll be deemed to also be filing for her own Social Security retirement benefits unless your child is either under age 16 or disabled. If your child isn't either under age 16 or disabled, your wife would then receive essentially the higher of her retirement or spousal rates, and her benefit rate would be reduced for age if she files prior to her full retirement age (FRA).
However, if your child is either under age 16 or disabled, then your wife could potentially qualify for child in care spousal benefits. In that case she wouldn't be required to file for her own retirement benefits and her spousal benefit rate would not be reduced for age.
Neither your wife nor your child can be paid benefits from your record until you start drawing your benefits. If they both qualify for benefits on your account, their benefit rates will be calculated by subtracting your PIA from the FMB and then splitting the remainder. If your PIA is $2866, that would give each of them an unreduced rate of roughly $1074 (i.e. ($5015-$2866)/2). But, your wife's rate would be subject to reduction for age if she doesn't qualify for child in care spousal benefits.
If both you and your wife filed for Social Security retirement benefits and your child qualifies on both records, your and your wife's FMBs could then be combined to potentially allow more total family benefits to be paid. I don't know whether or not that would be the best option in your case, but it's something to consider. You and your wife should strongly consider using our software to compare your various options so that you can choose the best possible strategy for claiming your benefits.