Guides & Articles
Long-form guides on personal finance, investing and home-buying that put the calculators on this site into context.
- Personal FinanceHow Much Life Insurance Do I Need, and for How Long?
The right amount of life insurance is the gap between what your family would need and what they would already have. That gap gets smaller every year, which changes how much and how long you should buy.
18 October 2026 · 8 min read - Personal FinanceSocial Security for Couples: Spousal and Survivor Benefits
For a married couple, Social Security is a household decision. The higher earner's claiming age sets the survivor benefit for whoever is left, and that can be worth more than a thousand dollars a month.
18 October 2026 · 8 min read - Personal FinanceThe £12,000 Cash ISA Limit: What Changes in April 2027
The overall ISA allowance stays at £20,000, but from April 2027 most savers under 65 can only put £12,000 of it into cash. Here is what that means in practice, and for whom it really matters.
18 October 2026 · 6 min read - HousingAre Mortgage Points Worth It? The Break-Even Math
A point costs 1% of the loan and buys a lower rate. Whether it pays off comes down to one question: how long you will keep the loan. Here is the arithmetic, done properly.
18 October 2026 · 7 min read - Personal FinanceRAP or IBR? Choosing a Student Loan Repayment Plan
If your federal loans were made before July 2026, you may be able to choose between RAP and IBR. Neither is always cheaper. Here is how to tell which suits you.
18 October 2026 · 8 min read - Personal FinanceNo Tax on Tips and Overtime: What It Really Saves You
The headlines said "no tax on tips" and "no tax on overtime". The reality is a set of deductions with limits and fine print. Here is what they actually save, worked through for real people.
18 October 2026 · 8 min read - Personal FinanceForm W-4 Explained: How Your Withholding Is Set
Each employer withholds as though its paycheck were your only income. For a couple earning $60,000 each, that leaves $4,360 a year unwithheld. Here is how the form fixes it, and how well.
17 October 2026 · 7 min read - Personal FinanceTake-Home Pay by State on a $100,000 Salary
A ranked table of what $100,000 takes home in 49 states and DC, each computed from its own 2026 brackets or flat rate and its own deductions, and why a state's top rate tells you so little.
12 September 2026 · 9 min read - Personal FinanceWhy You Got a Tax Refund (and What It Really Cost)
The "interest-free loan to the government" line is true, but it matters less than it sounds. Here's what a large refund really costs, and why aiming for zero is the wrong goal.
12 September 2026 · 6 min read - Personal FinanceTax Brackets Explained: Why a Raise Never Costs You
The idea that a raise can push you into a higher bracket and leave you worse off is the most stubborn myth in personal tax. Here's the arithmetic that puts it to rest.
12 September 2026 · 5 min read - Personal FinanceWhy Your Paycheck Is Smaller Than Your Salary
Being "in the 22% bracket" doesn't mean 22% of your salary goes in federal tax. On $78,000 it's 9.6%, and the deductions that outweigh it are the ones nobody mentions.
12 September 2026 · 6 min read - HousingWhat a Median Home Costs Per Month, by State (2026)
The same 20%-down, 30-year mortgage costs more than four times as much each month in Hawaii as in West Virginia, and that's before insurance, PMI or HOA fees.
8 September 2026 · 8 min read - HealthBody Fat vs BMI: Which Number Matters More?
BMI and body-fat percentage measure different things, and they disagree most for the people who most need an accurate number: athletes and older adults.
7 September 2026 · 6 min read - Personal FinanceUK Take-Home Pay 2026/27: Tax, NI and Student Loan
A salary well inside the £100,000-£125,140 taper band is taxed at a marginal rate most payslips never show, and Scotland taxes it more heavily still.
7 September 2026 · 6 min read - HousingWhat One Percentage Point Does to a Mortgage
One percentage point sounds small next to a mortgage rate, but on a typical loan it adds up to a five-figure sum by the end of the term.
7 September 2026 · 5 min read - Personal FinanceHSA vs 401(k): Where Should the Next Dollar Go?
The employer match always comes first, because nothing else pays a guaranteed return like it. After that, the HSA has a tax advantage the 401(k) doesn't.
7 September 2026 · 6 min read - Personal FinanceThe 50/30/20 Budget: How to Apply It to Your Paycheck
The 50/30/20 split only works on the money that actually reaches your account, and even then it can quietly fail in a way that has nothing to do with overspending.
7 September 2026 · 6 min read - Personal FinanceCompound Interest Explained with Real Numbers
The same stated rate gives different results depending on how often it compounds, and the rule of 72 is a genuinely handy shortcut once you know how far out it can be.
7 September 2026 · 6 min read - Personal FinanceHow Much Should You Have Saved for Retirement by Age?
A "3x salary by 40" target is a published guideline built on particular assumptions, not a law of retirement. Knowing what it assumes matters more than the number itself.
7 September 2026 · 6 min read - HousingDo Biweekly Mortgage Payments Actually Save Money?
Biweekly payments work because a year has 52 weeks, not because the schedule itself is special. The saving is real, and a do-it-yourself version gets almost all of it for free.
7 September 2026 · 6 min read - Housing15-Year vs 30-Year Mortgage: The Real Cost Difference
A 15-year mortgage always costs less in total interest. Whether it's the better choice depends on what you'd do with the money a 30-year frees up each month.
7 September 2026 · 7 min read - Personal FinanceRoth vs Traditional IRA in 2026: Which Wins?
The Roth-or-Traditional debate usually skips the one thing that actually decides it: whether your tax bracket in retirement will be higher, lower or the same as it is now.
7 September 2026 · 6 min read - HousingWhen Does PMI Drop Off? The 78% Rule Explained
PMI isn't forever, and you don't have to wait for your lender to notice. Two legal thresholds, 80% and 78% of the original value, set the timetable.
7 September 2026 · 6 min read - HousingHow Much House Can I Afford on an $80,000 Salary?
The 28/36 rule gives you a quick ceiling, but it answers the wrong question if you stop at principal and interest. Here's the full calculation on an $80,000 salary.
7 September 2026 · 7 min read - HealthBMI Explained: What the Number Means and Misses
BMI is the most widely used health number in the world, and one of the most misunderstood. It was built to describe populations, not people, which explains both why it has lasted and where it falls short.
6 August 2026 · 10 min read - Personal FinanceYour FIRE Number: the 4% Rule, Lean, Fat and Coast
The FIRE community has made popular a single number that tells you when you could retire early. The maths is simple, the variations matter, and the real-world caveats (taxes, healthcare and the order your returns arrive in) matter even more.
22 June 2026 · 10 min read - HousingUK Stamp Duty 2026: SDLT, LBTT and LTT Rates
England charges SDLT, Scotland charges LBTT and Wales charges LTT, each with its own rates and reliefs. This guide walks through all three for 2026, including the first-time buyer rules and the extra charge on additional properties.
22 June 2026 · 9 min read - Personal FinanceHow Inflation Doubles Your Retirement Number
Most retirement plans are worked out in today's money, but inflation doesn't stand still. Over a 30-year working life and 25 years of retirement, the gap is rarely small, and the pot you need can quietly double.
20 May 2026 · 10 min read - HousingHow to Save a 20% Down Payment: A Step-by-Step Plan
A down payment is the biggest single thing most people ever save for. With a plan and the right place to keep the money, it goes from daunting to doable.
20 May 2026 · 9 min read - HousingRent vs Buy: The Real Math Behind a Big Decision
Renting isn't "throwing money away", and buying isn't always the smart move. The real answer sits in five numbers most people never work out.
20 May 2026 · 10 min read - Personal FinanceLoan vs Invest: Borrow Now or Invest First?
Borrowing gets you what you want now, while investing builds wealth for later. Which makes more sense, a monthly loan payment or a monthly investment, comes down to three numbers, and the answer is often not what your gut says.
20 May 2026 · 9 min read