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savings-goals

计划并跟踪特定财务目标的储蓄,包括退休、教育和购房。当用户询问所需的储蓄率、529计划、退休积累目标、首付规划或目标优先级时使用。此外,当用户提到'我每个月需要存多少钱'、'我的退休计划是否在正轨上'、'大学储蓄'、'安全提款率'、'4%规则'、'FIRE储蓄率'、'追加供款'、'雇主匹配',或者询问如何平衡相互竞争的储蓄目标时也触发。

person作者: jakexiaohubgithub

Savings Goals

Core Concepts

Required Monthly Savings

To accumulate a future value FV in n periods at rate r per period:

PMT = FV × r / [(1+r)^n - 1]

This is the sinking fund formula (future value of annuity solved for PMT).

Inflation-Adjusted Targets

Always compute goals in future (nominal) dollars:

FV_nominal = FV_today × (1 + inflation)^years

Then solve for the required savings using the nominal return, or use the real return with today's dollars.

Education Funding

  • 529 plans: tax-free growth for qualified education expenses, state tax deductions in many states
  • Current costs (2025-26, total cost of attendance, College Board Trends in College Pricing): ~$30K/year (public four-year in-state) to ~$65K/year (private nonprofit), growing ~5%/year
  • Front-loading: maximize early contributions for compound growth
  • Superfunding: 5-year gift tax averaging (contribute 5× annual exclusion at once)
  • Financial aid impact: parent-owned 529 assets are assessed at a maximum of 5.64% in the federal Student Aid Index (SAI) formula — FAFSA has used the SAI in place of the Expected Family Contribution (EFC) since the 2024-25 award year

Retirement Accumulation

  • Target nest egg: annual spending need / safe withdrawal rate
    • Example: $80K/year spending / 0.04 = $2,000,000
  • Safe withdrawal rate: traditionally 4% (Bengen rule), adjusted for fees, taxes, longevity
  • Required savings rate: depends on starting age, current savings, expected returns
  • Employer match: always capture full match — it's an immediate 50-100% return
  • Catch-up contributions: additional 401(k)/IRA contributions allowed after age 50

Down Payment Saving

  • Typical target: 20% of home price (avoids PMI)
  • Timeline: typically 2-7 years → conservative allocation (HYSA, short-term bonds)
  • Include closing costs (2-5% of purchase price) in savings target

Goal Priority Framework

Recommended priority order:

  1. Emergency fund (3-6 months expenses)
  2. Employer 401(k) match (free money)
  3. High-interest debt payoff (>6-8% rate)
  4. HSA (triple tax advantage if eligible)
  5. Max retirement accounts (401k, IRA, Roth)
  6. Education funding (529)
  7. Other goals (home, vacation, etc.)

Multiple Goal Balancing

  • Allocate savings across goals based on priority, timeline, and flexibility
  • Non-negotiable goals (retirement) take precedence over flexible goals
  • Shorter timelines need more conservative investment allocation
  • Use goal-based investing: separate sub-portfolios per goal with appropriate risk

Savings Rate Benchmarks

  • Minimum: 15% of gross income for retirement (including employer match)
  • Aggressive: 25-50%+ for early retirement / FIRE
  • Savings rate = total savings / gross income

Key Formulas

| Formula | Expression | Use Case | |---------|-----------|----------| | Required savings (PMT) | PMT = FV × r / [(1+r)^n - 1] | Monthly savings for a goal | | Future value with savings | FV = PV(1+r)^n + PMT×[(1+r)^n - 1]/r | Project goal balance | | Inflation adjustment | FV_real = FV_today × (1+π)^t | Convert today's dollars to future | | Retirement target | Nest egg = annual spend / SWR | Size the retirement goal | | Years to goal | n = ln(FV×r/PMT + 1) / ln(1+r) | How long until goal is funded | | Savings rate | SR = total savings / gross income | Track savings discipline |

Worked Examples

Example 1: College Savings (529)

Given: Need $200,000 in 18 years, expect 7% annual return, starting from $0 Calculate: Required monthly savings Solution:

  • Monthly rate: r = 0.07/12 = 0.005833
  • Months: n = 18 × 12 = 216
  • PMT = $200,000 × 0.005833 / [(1.005833)^216 - 1]
  • PMT = $1,166.67 / [3.5125 - 1]
  • PMT = $1,166.67 / 2.5125 = $464.34/month

Example 2: Retirement Accumulation

Given: Age 30, $50,000 currently saved, wants $2,000,000 by age 65, expects 8% annual return Calculate: Required monthly savings Solution:

  • Monthly rate: r = 0.08/12 = 0.006667; months: n = 35 × 12 = 420
  • FV of current savings (monthly compounding): $50,000 × (1.006667)^420 = $50,000 × 16.2925 = $814,627
  • Remaining needed: $2,000,000 - $814,627 = $1,185,373
  • PMT = $1,185,373 × 0.006667 / [(1.006667)^420 - 1]
  • PMT = $7,902.49 / [16.2925 - 1]
  • PMT = $7,902.49 / 15.2925 = $517/month
  • With employer match of $200/mo: personal contribution = $317/month

Common Pitfalls

  • Not inflation-adjusting future goals (college in 18 years costs much more than today)
  • Neglecting employer match — it's the highest guaranteed return available
  • Too conservative allocation for long-horizon goals (20+ years can tolerate equity risk)
  • Saving for college before adequately funding retirement (retirement has no financial aid)
  • Not revisiting savings rate as income grows (lifestyle creep absorbs raises)
  • Using average returns without considering sequence risk near goal date

Cross-References

  • time-value-of-money (core plugin): FV/PV calculations, annuity formulas
  • emergency-fund (wealth-management plugin): must be funded before other goals
  • debt-management (wealth-management plugin): high-interest debt payoff competes with savings
  • tax-efficiency (wealth-management plugin): 529 tax benefits, Roth vs traditional, HSA
  • investment-policy (wealth-management plugin): goal-based allocation aligns with IPS constraints
  • asset-allocation (wealth-management plugin): glide paths for target-date retirement savings
  • finance-psychology (wealth-management plugin): mental accounting, present bias, commitment devices
  • financial-planning-workflow (advisory-practice plugin): savings goals are key inputs to the comprehensive financial planning process
  • insurance-planning (wealth-management plugin): education and survivor-income goals feed the capital-needs calculation for life insurance sizing
  • estate-gifting (wealth-management plugin): 529 superfunding (5-year gift-tax election) lets grandparents front-load education goals within annual exclusions
  • retirement-decumulation (wealth-management plugin): the drawdown-side counterpart — safe withdrawal rates and spending rules for the nest egg accumulated here

Running the script

Run the reference implementation directly:

uv run scripts/savings_goals.py      # PEP 723 header resolves dependencies automatically
python3 scripts/savings_goals.py     # standard library only — no installs needed

A bare run prints a demo covering required monthly savings, retirement accumulation, time-to-goal, inflation adjustment, shortfall analysis, education funding, savings rate, and real returns. Use --verify to recompute the demo figures and assert they match this skill's worked examples (prints PASS/FAIL, exits nonzero on mismatch), and --help to list the available classes and functions. The file is primarily meant to be imported as a module (from savings_goals import SavingsGoals) rather than run standalone.