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A plan runs short in a year when income, plus every account your withdrawal order can draw from, can’t pay that year’s spending and taxes. CoastMath doesn’t cut the spending. It records the unpaid amount as unfunded spending, carries it forward, and subtracts it from net worth until later cash repays it.
The first year this happens is the plan’s failure year. It stays the failure year even if the plan recovers, and the Overview shows Spending unfunded from that year under the plan name.
Each year, after income, spending and savings rules, CoastMath withdraws what’s needed in your withdrawal order. Whatever is still uncovered is added to the unfunded balance. Every year after that, once the year’s own spending is paid, it tries to repay the whole carried balance the same way, so surplus a later year deposits goes straight back out to clear it. Homes and other property with Auto-liquidate on depletion turned on are sold at that point to cover it, other property before a primary home.
A 60-year-old spends $60,000 a year from $120,000 of savings until a $90,000 pension starts at 64. Savings run out in 2028; each pension year’s surplus repays the balance until it clears in 2035. The plan’s failure year stays 2028.
Show data
| Year | Unfunded spending carried |
|---|---|
| 2026 | $0 |
| 2027 | $0 |
| 2028 | $55,189 |
| 2029 | $115,189 |
| 2030 | $96,159 |
| 2031 | $76,678 |
| 2032 | $57,197 |
| 2033 | $37,716 |
| 2034 | $18,235 |
| 2035 | $0 |
| 2036 | $0 |
While a balance is carried it lowers net worth, so net worth can be negative with no debts at all: in 2029 it’s −$115,189. It also counts against the estate at the end of the plan.
An expense set to Fund from a specific account draws only from the accounts you selected, in their listed order. If they can’t cover it, the rest goes unpaid and CoastMath doesn’t fall back to your other accounts. That unpaid amount is never repaid from other accounts or from later cash, so it stays in net worth for the rest of the plan. It also sets the failure year, even when other accounts hold plenty.
| Checking at the end of 2040 | $32,924 | |
|---|---|---|
| − | Unfunded spending carriedTravel checking couldn’t pay from 2027 to 2037 | $160,058 |
| = | Net worth | −$127,134 |
The same plan as above, with the travel expense added. Checking refills from 2036, but the unpaid travel stays.
Start at the failure year: select it on the Overview’s net worth chart. The year ledger shows Unfunded spending in red, and the cash-flow diagram shows a Shortfall flowing into after-tax cash. Then look at what changed that year or just before, in rough order of how often it’s the cause:
- Income stopped at a retirement milestone before other income started, and savings couldn’t bridge the gap.
- A large expense started or recurred, or spending grows faster than income.
- An account holding money isn’t in your withdrawal order, so it’s never drawn. New accounts are added automatically except 529 plans.
- The expense is paid from specific accounts that ran dry, as described above.
- A home or other property holds the value, but Auto-liquidate on depletion is off and no sale is scheduled; see Selling a home or property.
- An account paying a substantially equal periodic payment series gives only its scheduled payment until the series ends.
The failure year belongs to this one steady-return projection. Success odds reruns the plan across many return sequences and counts how many run short, so a plan can be funded here and still fail in some trials, or the reverse; see Why the projection and success odds differ.