Coast FIRE and Social Security: Claim at 62, 67 or 70?
Your portfolio pays everything until the first check. After that, it only pays the gap.
TL;DR
- At 30, retiring at 65 on $4,000 a month, your Coast FIRE number is $217,548. With $2,000 a month of Social Security from 67, it drops to $116,981. That's 46% less.
- Before the first check, your portfolio pays all of your spending. After it, the portfolio pays only the gap.
- Claiming at 70 needs the least invested today in every case below. The bigger check is worth more than the extra bridge years cost.
- Your benefit at full retirement age is on your Social Security Statement at ssa.gov/myaccount.
Social Security cuts the Coast FIRE number almost in half in the default case. Say you're 30, spend $4,000 a month and want to retire at 65. Without Social Security, you need $217,548 invested today. With $2,000 a month from 67, you need $116,981.
Every number here assumes 5% a year after inflation and a 4% withdrawal rate. All amounts are in today's money. They come from the Coast FIRE calculator.
How Social Security changes the Coast number
Your Coast FIRE number is the amount that grows to your target by retirement with no more saving. Without Social Security, the target is your FIRE number: a year of spending divided by your withdrawal rate. $4,000 a month is $48,000 a year. At 4%, that's $1,200,000.
The bridge years
Retire at 65 and claim at 67. For those two years, your portfolio pays the full $48,000 a year. These are the bridge years.
The gap after the first check
From 67, Social Security pays $2,000 a month. Your portfolio pays the other $2,000. That's $24,000 a year for life. At 4%, it takes $600,000.
Add the two bridge years. The target at 65 becomes $645,266. Divide it by 1.05 for each of the 35 years from 30 to 65. You get $116,981.
Target at retirement = the bridge years at full spending + the gap after, each year valued at your withdrawal rate. Coast FIRE number = target ÷ 1.05 ^ years to retirement.
If the checks started the day you retired, the target would be $600,000. Waiting two years adds $45,266.
Coast FIRE numbers with Social Security
Your statement shows your benefit at full retirement age. That's 67 for anyone born in 1960 or later. Claim at 62 and you get 70% of it (SSA). Wait until 70 and you get 124%, from an 8% credit for each year past 67 (SSA).
The tables use two statement figures: $1,500 and $2,500 a month at 67. Each row shows the check at that claim age. Spending is $4,000 a month throughout. The last two columns are what you need invested today at 30 and at 40.
Retire at 55
| Social Security | Needed at 55 | Invested at 30 | Invested at 40 |
|---|---|---|---|
| None | $1,200,000 | $354,363 | $577,221 |
| $1,050/mo from 62 ($1,500 at 67) | $960,626 | $283,675 | $462,077 |
| $1,500/mo from 67 | $918,931 | $271,363 | $442,022 |
| $1,860/mo from 70 ($1,500 at 67) | $890,162 | $262,867 | $428,183 |
| $1,750/mo from 62 ($2,500 at 67) | $801,043 | $236,550 | $385,315 |
| $2,500/mo from 67 | $731,552 | $216,029 | $351,889 |
| $3,100/mo from 70 ($2,500 at 67) | $683,604 | $201,870 | $328,825 |
Retire at 60
| Social Security | Needed at 60 | Invested at 30 | Invested at 40 |
|---|---|---|---|
| None | $1,200,000 | $277,653 | $452,267 |
| $1,050/mo from 62 ($1,500 at 67) | $908,765 | $210,268 | $342,504 |
| $1,500/mo from 67 | $858,037 | $198,530 | $323,385 |
| $1,860/mo from 70 ($1,500 at 67) | $823,035 | $190,432 | $310,193 |
| $1,750/mo from 62 ($2,500 at 67) | $714,608 | $165,344 | $269,328 |
| $2,500/mo from 67 | $630,062 | $145,782 | $237,464 |
| $3,100/mo from 70 ($2,500 at 67) | $571,725 | $132,284 | $215,477 |
Retire at 65
| Social Security | Needed at 65 | Invested at 30 | Invested at 40 |
|---|---|---|---|
| None | $1,200,000 | $217,548 | $354,363 |
| $1,050/mo from 62 ($1,500 at 67) | $885,000 | $160,442 | $261,343 |
| $1,500/mo from 67 | $783,950 | $142,122 | $231,503 |
| $1,860/mo from 70 ($1,500 at 67) | $741,365 | $134,402 | $218,927 |
| $1,750/mo from 62 ($2,500 at 67) | $675,000 | $122,371 | $199,329 |
| $2,500/mo from 67 | $506,583 | $91,839 | $149,595 |
| $3,100/mo from 70 ($2,500 at 67) | $435,608 | $78,971 | $128,636 |
Retire at 55 and Social Security does less. The portfolio pays 7 to 15 bridge years before the first check. With a $1,500 statement figure, a 30-year-old still needs $262,867 to $283,675.
Retire at 65 and it does the most. A $2,500 statement figure claimed at 70 cuts the number at 30 from $217,548 to $78,971.
Every starting age: 25, 30, 35, 40 and 45
Retire at 55, invested today by age
| Social Security | Needed at 55 | At 25 | At 30 | At 35 | At 40 | At 45 |
|---|---|---|---|---|---|---|
| None | $1,200,000 | $277,653 | $354,363 | $452,267 | $577,221 | $736,696 |
| $1,050/mo from 62 | $960,626 | $222,267 | $283,675 | $362,050 | $462,077 | $589,741 |
| $1,500/mo from 67 | $918,931 | $212,620 | $271,363 | $346,336 | $442,022 | $564,144 |
| $1,860/mo from 70 | $890,162 | $205,964 | $262,867 | $335,493 | $428,183 | $546,482 |
| $1,750/mo from 62 | $801,043 | $185,343 | $236,550 | $301,905 | $385,315 | $491,771 |
| $2,500/mo from 67 | $731,552 | $169,265 | $216,029 | $275,714 | $351,889 | $449,110 |
| $3,100/mo from 70 | $683,604 | $158,171 | $201,870 | $257,643 | $328,825 | $419,674 |
Retire at 60, invested today by age
| Social Security | Needed at 60 | At 25 | At 30 | At 35 | At 40 | At 45 |
|---|---|---|---|---|---|---|
| None | $1,200,000 | $217,548 | $277,653 | $354,363 | $452,267 | $577,221 |
| $1,050/mo from 62 | $908,765 | $164,750 | $210,268 | $268,361 | $342,504 | $437,131 |
| $1,500/mo from 67 | $858,037 | $155,554 | $198,530 | $253,381 | $323,385 | $412,730 |
| $1,860/mo from 70 | $823,035 | $149,208 | $190,432 | $243,045 | $310,193 | $395,894 |
| $1,750/mo from 62 | $714,608 | $129,551 | $165,344 | $211,026 | $269,328 | $343,739 |
| $2,500/mo from 67 | $630,062 | $114,224 | $145,782 | $186,059 | $237,464 | $303,070 |
| $3,100/mo from 70 | $571,725 | $103,648 | $132,284 | $168,832 | $215,477 | $275,010 |
Retire at 65, invested today by age
| Social Security | Needed at 65 | At 25 | At 30 | At 35 | At 40 | At 45 |
|---|---|---|---|---|---|---|
| None | $1,200,000 | $170,455 | $217,548 | $277,653 | $354,363 | $452,267 |
| $1,050/mo from 62 | $885,000 | $125,710 | $160,442 | $204,769 | $261,343 | $333,547 |
| $1,500/mo from 67 | $783,950 | $111,357 | $142,122 | $181,388 | $231,503 | $295,462 |
| $1,860/mo from 70 | $741,365 | $105,308 | $134,402 | $171,535 | $218,927 | $279,413 |
| $1,750/mo from 62 | $675,000 | $95,881 | $122,371 | $156,180 | $199,329 | $254,400 |
| $2,500/mo from 67 | $506,583 | $71,958 | $91,839 | $117,212 | $149,595 | $190,926 |
| $3,100/mo from 70 | $435,608 | $61,876 | $78,971 | $100,790 | $128,636 | $164,176 |
Claim at 62, 67 or 70?
In this model, claiming at 70 needs the least invested today. That holds in every row above, even with more bridge years. The Social Security break-even calculator gives the crossover ages for your own statement figure.
Take a $2,500 statement figure and retire at 65. Claim at 62 and the target is $675,000. Claim at 70 and it's $435,608. At 30, that's $122,371 against $78,971 invested today.
The check at 70 is 77% bigger than the check at 62. It lasts for life. The bridge years end. At a 4% withdrawal rate, every lifelong dollar a month is worth $300 of portfolio.
The trade-off
The model treats the money as if it has to last for life. That's the right test for a plan you can't redo at 85.
If you die early, claiming early would have paid more. A claimer at 62 gets eight years of checks before a claimer at 70 gets one. With a $2,500 statement figure, that's $168,000. The claimer at 70 catches up around age 80. That count uses today's money with no interest.
Against 67, the gaps are shorter. Claiming at 67 passes 62 at about 79, and 70 passes 67 at about 82.
Benefits can change too. The 2026 Trustees Report projects the retirement trust fund runs out in late 2032. From then on, incoming taxes cover 78% of scheduled benefits.
To test that, enter 78% of your benefit. $2,000 becomes $1,560 a month. The Coast FIRE number at 30 then rises from $116,981 to $139,105.
Where to find your benefit
Sign in to my Social Security to get your Social Security Statement. It estimates your benefit at different claim ages.
The calculator takes the monthly check at the age you claim it. Claiming at 62? Enter 70% of your full-retirement-age figure. Claiming at 70? Enter 124%.
What the Coast calculator leaves out
The Coast FIRE calculator takes one benefit and the age it starts. Three things stay outside it:
- Spousal benefits. A spouse can get up to 50% of your benefit at full retirement age (SSA).
- The earnings test. Claim before full retirement age while still working, and SSA holds back $1 for every $2 you earn above $24,480 in 2026 (SSA).
- Taxes on benefits. Part of your benefit can count as taxable income, depending on your other income.
The Fire Planner covers two of these with US taxes on. You enter your statement figure and claim age. It adds the spousal top-up for a partner. It taxes your benefit every year with the rest of your income. With no statement, it estimates your benefit from your salary history. A Social Security cut stress test shows what a smaller check does to your plan. The earnings test stays out of the planner too.
Run your own numbers
Open the Coast FIRE calculator. Enter your check under “Social Security or pension”, with the age it starts. A pension works the same way. The calculator's link to the Fire Planner carries both.
Frequently Asked Questions
The standard formula leaves it out: your FIRE number divided by growth, with your portfolio paying all of your spending for life. Adding Social Security lowers the target at retirement. At 30, retiring at 65 on $4,000 a month, $2,000 a month from 67 cuts the Coast FIRE number from $217,548 to $116,981. The Coast FIRE calculator takes the benefit and the age it starts.
In this model, 70 needs the least invested today. With a $2,500 statement figure and retirement at 65, a 30-year-old needs $78,971 claiming at 70. Claiming at 62 needs $122,371. Claiming early pays more in total if you die before about 80. It also needs fewer bridge years, which matters if you retire early with little outside the portfolio.
Your benefit, your claim age, your Coast FIRE number. No sign-up.