Personal money

Budgets, debt, saving and retirement, each decision worked through with the arithmetic shown.

• How Much Life Insurance Do I Need? Calculator and DIME Method

  How much life insurance you need, worked two ways: the DIME method ($1,075,000 in the example) and needs minus what you have ($1,022,059).

• Pension Lump Sum vs Annuity Calculator: The Return You Are Offered

  Should you take the pension lump sum? Work out the return the annuity pays and the break-even age. Example: $2,400 a month or $400,000.

• Social Security Break Even Calculator: 62 vs 67 vs 70

  When to take Social Security, worked out. On a $2,000 benefit, 62 pays $1,400, 70 pays $2,480, and waiting catches up at age 80.4.

• Compound Interest Calculator With Monthly Contributions, Worked

  Compound interest with monthly contributions, worked: $10,000 plus $300 a month at an example 6% for 20 years ends at $171,714.31. Formula and withdrawals.

• Roth vs Traditional 401k Calculator (With Employer Match)

  Roth vs traditional 401(k) comes down to two tax rates: yours today and yours in retirement. Worked with a match, which lands pre-tax either way.

• 50/30/20 Budget Calculator: The Rule, Worked on a Paycheck

  The 50/30/20 budget rule as a calculator. Take-home pay of $4,800 splits into $2,400, $1,440 and $960, plus what biweekly pay changes.

• Car Affordability Calculator Based on Income: Budget the Total

  How much car you can afford on your income, worked backward from the payment formula - and why budgeting the payment alone overshoots by $18,803.

• Coast FIRE Calculator With Inflation: The Formula and a Worked Example

  Coast FIRE is your FIRE number discounted at the real return. The formula, a worked example ($462,932 today), and the inflation mistake that halves it.

• Daycare vs Nanny Cost: Is a Nanny Cheaper Than Daycare?

  Daycare is billed per child, a nanny per household - plus employer payroll tax. Worked example of daycare vs nanny cost a year and a month.

• Net Worth Calculator: How to Calculate Net Worth, With a Mortgage

  How to calculate net worth, step by step, including a mortgage. A worked example where $558,000 owned minus $303,200 owed leaves $254,800.

• Capitalized Interest on Student Loans: What a Pause Actually Costs

  Capitalized interest means unpaid interest is added to your student loan balance. A 12-month pause on $38,000 at 6.8% costs $4,733.93. The math.

• Sinking Funds: Meaning, Categories, and How to Calculate Each One

  A sinking fund turns a known future bill into a monthly amount. The formula, a $7,140 example that becomes $595 a month, and how to catch up late.

• Wedding Budget Breakdown: Fixed Costs and the Real Cost per Guest

  An illustrative $28,950 wedding averages $241.25 a guest, but one more guest costs $144. The fixed vs per-guest breakdown, worked.

• The 100 Envelope Challenge: How Much It Totals, and a Pace You Can Keep

  The 100 envelope challenge totals $5,050. What that means week by week, the worst week you can draw, and gentler versions if it's too much.

• Debt Snowball vs Avalanche: What the Order Actually Costs, Worked Through

  Avalanche is mathematically optimal - but by how much? Two worked examples: one where snowball costs $104.43, one where it costs $1,450.67.