First, each spouse needs to go to https://www.ssa.gov/myaccount/ & set up an account.
Then, plug her earnings record into this calculator. It’s much more intuitive & user friendly than SSA’s version. https://ssa.tools/calculator.html
Also, have them read this article: https://www.kitces.com/blog/why-it-rarely-pays-for-both-spou…
TL;DR version- yes, lower earning spouse will earn a smaller spousal benefit by claiming early. Roughly 10% lower than if she waited until 66 yr & 6 months, her Full Retirement Age (FRA).
https://www.aarp.org/retirement/social-security/questions-an…
Exact math- https://www.ssa.gov/oact/quickcalc/early_late.html
“In the case of early retirement, a benefit is reduced 5/9 of one percent (5/9* 0.01= 0.00555) for each month before normal retirement age, up to 36 months.” She’s 18 months early, so 18 x 0.00555= 0.0999 or 10% reduction.
That reduction is forever. When she draws spousal benefits after DH takes SSI at 70, she will get a plus up calculated from her own theoretical benefit at FRA (66.5) + her spousal benefit. The two numbers together can’t exceed 50% of husband’s benefit at FRA.
Note- DH gets delayed retirement credits by waiting until 70, but spousal benefits are capped at 50% of his FRA number, not his age 70 number.
Example. DW FRA benefit= $500/month. DH FRA benefit $2000/month.
If they both took SSI at FRA, she would get 500 (her benefit) + $500 (spousal benefit to get her to 50% of DH’s FRA number)= $1000, or 50% of DH’s $2000 FRA benefit.
By claiming 18 months early at 65, her benefit is now cut by 10%, so $450/month.
When DH draws SSI at 70, DW gets the same $500 spousal plus up she would have gotten at age 66.5, but her total benefit is only $950 because her benefit is reduced forever.
It’s a building block technique & she shortened the height of her ‘block’ by claiming early.
Important note- Spousal benefits can’t happen until higher earning spouse draws his benefit, so it’ll just just her benefit from 65 to 70.
Also- DH’s 128% larger (3.5 years x 8% credit/yr) age 70 benefit becomes the couple’s survivor benefit. Whoever dies first, the survivor draws DH’s benefit. Basically the lower earning spouse’s benefit stops.
As the Kitces article points out, it rarely pays for lower earning spouse to wait.