What Is My Coast FIRE Number? A Table for Every Age (18–75)

Your Coast FIRE number is a single figure: the amount you need invested today so that, from this point on, the market's growth alone carries you to your full retirement number. You stop saving. You don't stop living. The math below shows you exactly where you stand, at any age from 18 to 75.

The one formula behind the number

Full FIRE is your annual spending multiplied by 25 — the classic safe withdrawal rate of 4% inverted. If you'll need $50,000 a year in retirement, your full number is $1,250,000. That's the destination.

Your Coast FIRE number is that destination pulled back to today, discounted at your expected real return. The formula is:

Coast FIRE number = Full FIRE number ÷ (1 + real return)^(years until full FIRE)

$1,250,000 ÷ (1.07)^35 ≈ $117,000 if you're 30, targeting 65, at a 7% real return. That $117,000 is the number you're "coasting" from.

Once your invested assets reach that number, you've technically won the game. Everything after it is a bonus. You can keep working — but for a paycheck you actually want, at a pace you choose — because your retirement is already funded by compounding.

The full table, age 18 to 75

Assumptions: full FIRE target = $1,250,000 (i.e., $50,000/year at 4%), target retirement age = 65, real return = 7%/year. "Needed today" is the Coast FIRE number for that current age.

Age	Needed today	Years to 65
18	$51,984	47
19	$55,623	46
20	$59,517	45
21	$63,683	44
22	$68,141	43
23	$72,911	42
24	$78,014	41
25	$83,475	40
26	$89,319	39
27	$95,571	38
28	$102,261	37
29	$109,419	36
30	$117,079	35
31	$125,274	34
32	$134,043	33
33	$143,426	32
34	$153,466	31
35	$164,209	30
36	$175,704	29
37	$188,003	28
38	$201,163	27
39	$215,244	26
40	$230,311	25
41	$246,433	24
42	$263,684	23
43	$282,141	22
44	$301,891	21
45	$323,024	20
46	$345,635	19
47	$369,830	18
48	$395,718	17
49	$423,418	16
50	$453,058	15
51	$484,772	14
52	$518,706	13
53	$555,015	12
54	$593,866	11
55	$635,437	10
56	$679,917	9
57	$727,511	8
58	$778,437	7
59	$832,928	6
60	$891,233	5
61	$953,619	4
62	$1,020,372	3
63	$1,091,798	2
64	$1,168,224	1
65	$1,250,000	0
66–75	—	Coast window closed — you've reached (or passed) full FIRE age. The number to track is now your full FIRE number, not the coast number.

How to read this:

Find your current age. That row's "Needed today" is your Coast FIRE number under these assumptions. If your invested assets already equal or exceed it, you've coasted. If not, the gap is how much more you need to save before you can stop — and it shrinks every year you wait, which is exactly why starting early is so powerful.

What the table is really telling you

The steep part is at the young end

Between 18 and 30, the number moves from $52,000 to $117,000 — it roughly doubles. That's the compounding window doing its heaviest lifting. Each year you're younger, the market gets more time, and the amount you need today gets dramatically smaller.

The middle is the "normal" range

Ages 30 to 55 span $117,000 to $635,000. This is where most people are when they first hear the term "Coast FIRE." The number is large enough to feel intimidating, but it's a one-time target, not a monthly bill.

The old end is mostly a footnote

From 55 to 65 the number climbs from $635,000 to the full $1,250,000, and after 65 the concept collapses into ordinary full FIRE. If you're past 65, you're no longer coasting — you're either there or you're saving toward a conventional retirement. The table's job is done.

Three assumptions to adjust before you trust the number

Your spending. The table uses $50,000/year. If you'll need $40,000, multiply every figure by 0.8. If $60,000, multiply by 1.2. This is the biggest lever — your target number scales linearly with your spending.
Your target age. The table assumes 65. Retire at 60 and you have fewer years to compound, so every "needed today" figure rises. Retire at 70 and they fall.
Your expected return. 7% real is a common planning assumption. Use 6% and the numbers go up; 8% and they go down. A one-point change in return moves the whole table meaningfully over a 35-year horizon.

Fast re-scale rule:

Coast FIRE number scales as 1/(1+r)^n. Halve your spending and you roughly halve the number. Add five years to your horizon (you're younger than you thought) and the number drops by a factor of about (1.07)^5 ≈ 1.4 — i.e., about 28% less. These are the two dials worth turning first.

Once you hit the number, what actually changes

Reaching your Coast FIRE number doesn't mean you stop working — it means you stop needing to. The paycheck becomes optional rather than mandatory. Your options include:

Switching to a lower-paying job you'd actually enjoy, now that the money isn't the point.
Cutting hours, remote work, or sabbaticals without the panic of a shrinking account.
Redirecting the savings you no longer need toward a home, a family, or a business you care about.
Simply letting the account grow untouched, which is the most common (and least dramatic) outcome.

The psychological shift is the real payoff: the account is no longer a countdown to a deadline. It's a floor you've already cleared.

The bottom line:

Your Coast FIRE number is the smallest amount of money that, if you had it today, would let you stop saving entirely and let the market finish the job. The table above gives you that figure for every age from 18 to 75. Find your row, adjust for your actual spending and target date, and you'll know — to the dollar — whether you're coasting yet.