CALCMONEY // GUIDES
Blog.
Numbers-first guides on mortgages, taxes, retirement, and net worth. No opinions, no fluff.
How to Calculate VAT on International Transactions and Reclaim Input Tax
Most US businesses selling or buying across borders miscalculate VAT and leave recoverable input tax on the table. The math is straightforward, but the jurisdiction rules are not. Here is exactly how to get the numbers right.
How to Calculate What Percentage of Your Salary Goes to Taxes
Most Americans confuse their marginal tax rate with their actual tax burden, and that mistake distorts every financial decision they make. Your effective tax rate is the only number that tells you what you actually paid. Here is exactly how to calculate it.
How to Calculate a Seller-Paid Rate Buy-Down (With Real Numbers)
Most buyers treat seller concessions as a discount on closing costs. That's the wrong frame. A seller-paid rate buy-down can cut your monthly payment by hundreds and save tens of thousands over the loan's life. The math is straightforward once you know what to ask for.
Charitable Deduction Bunching: The Math That Turns Donations Into Real Tax Savings
Most donors give the same amount every year and never claim a single dollar of itemized deduction. Bunching charitable contributions into alternating years can generate thousands in additional tax savings without changing your total generosity. The math is straightforward once you know the threshold.
How to Calculate the Value of an Assumable Mortgage in a High Rate Market
Most buyers ignore assumable mortgages entirely. That oversight can cost them tens of thousands of dollars over the life of a loan. Here is the exact math for quantifying what a below-market rate is actually worth.
How to Calculate the Credit Score Boost You'll Actually Get as an Authorized User
Most people add themselves as an authorized user and wait, with no idea whether they'll gain 20 points or 80. The boost is calculable before you make the call. Knowing the variables in advance tells you which accounts to target and which ones to skip.
How to Calculate Business Use of Home Percentage for Tax Deductions
Most self-employed workers calculate their home office deduction on gut feel, not square footage. That guess costs them hundreds of dollars per year in legitimate deductions they simply leave on the table. The correct method takes under ten minutes and produces a defensible number the IRS will accept.
Current Dividend Yield vs Trailing Yield: You're Probably Using the Wrong Number
Most investors quote dividend yield from a screenshot, not a calculation. That single habit distorts income projections by hundreds of dollars per year. Current yield and trailing yield measure different things, and confusing them changes every decision you make about income-generating holdings.
How to Calculate the Right Auto Insurance Deductible for Your Situation
Most drivers pick a deductible based on a gut feeling and leave hundreds of dollars on the table every year. Calculating the right deductible is a math problem, not a preference. The analysis takes under five minutes and changes the answer entirely.
CalcMoney vs Calculator.net: Which Financial Calculator Is More Accurate
Most online financial calculators produce numbers that look precise but hide dangerous assumptions. The difference between a tool that models reality and one that models a textbook costs real money. Calculator.net falls short in several key areas, and this comparison shows what CalcMoney does differently.
401k Rollover to IRA Calculator: Direct vs Indirect Rollover, Tax Impact
A direct rollover is $0 in taxes. An indirect rollover triggers 20% mandatory withholding and a 60-day clock. Here's how to do it right and whether you should at all.
1099 vs W2 Calculator: How Much More Do You Need to Earn as a Contractor?
To match a $80K W2 job as a 1099 contractor, you need to earn $110K-$118K. Here's the full calculation including taxes, benefits, and how to price your rate.
72(t) SEPP Calculator: Early IRA Withdrawal at Any Age
A 72t distribution plan on a $600,000 IRA at 5% IRS-allowed rate pays $30,000/year starting at age 50. You avoid the 10% early withdrawal penalty. Miss a single payment, and the penalty applies retroactively to all distributions.
1031 Exchange Calculator: How to Defer Capital Gains on Real Estate
Selling a rental property with $300,000 in gains triggers $86,400 in federal and state taxes. A 1031 exchange defers the entire bill. Here is the math and the strict IRS rules you must follow.
How to Calculate Stock Portfolio Percentage Allocation and Rebalance to Target
Most investors know what they own but not what percentage they actually hold. A portfolio that started at a disciplined 60/40 split can drift to 75/25 after a single bull run, exposing you to far more risk than you intended. Here is the exact math to measure drift and trade back to target.
Calculate Your Real Investment Return After All Taxes
Gross returns are a fiction. After federal income tax, state tax, and inflation, a reported 10% annual gain can shrink to under 5% in real purchasing power. Most investors never run the actual number.
How to Calculate XIRR for Investments With Irregular Cash Flows
Standard IRR assumes your cash flows arrive at perfectly equal intervals. Real investments never work that way. XIRR fixes that, and the difference in your calculated return can exceed 3 percentage points on a typical portfolio.
How to Calculate Year-Over-Year Growth Rate for Your Investment Portfolio
Most investors quote their portfolio returns incorrectly. They confuse absolute dollar gains with actual growth rate, and that gap distorts every allocation decision they make. Here is the exact method professionals use.
How to Calculate Your Savings Rate as a Percentage of Income (And Why You're Probably Using the Wrong Number)
Most people calculate their savings rate wrong. They use gross income as the denominator, which deflates their true rate and distorts every projection they make. Here is the correct method, the math behind it, and what a accurate savings rate actually tells you about your financial position.
CalcMoney vs Dinkytown: Which Calculator Actually Earns Its Place in Your Financial Toolkit
Most financial calculators were built for classrooms, not capital allocation decisions. Dinkytown has served a purpose for decades, but the gap between what it shows and what you actually need to know is costing you precision where precision matters most.
The 10 Best Free Financial Calculators in 2026 (Ranked by Usefulness)
The best financial calculators are the ones that give you clear numbers without making you wade through ads or paywalls. Here's the honest category-by-category breakdown.
Annuity Calculator: Should You Take the Lump Sum or Monthly Payments?
A $500,000 pension lump sum vs $2,800/month for life. Which is worth more? The answer depends on your age, life expectancy, and what you'd do with the lump sum.
Break-Even Calculator: How Many Sales Before Your Business Is Profitable?
A coffee shop with $8,000/month in fixed costs, $4 average ticket, and $1.20 COGS needs to sell 2,857 cups before making a cent. Here's the formula and how to use it.
AMT Calculator: Who Pays the Alternative Minimum Tax and How to Avoid It
The AMT exemption in 2026 is $89,075 for single filers. Most middle-income earners owe nothing. But if you exercise ISOs or have large itemized deductions, the AMT can cost tens of thousands. Here is how to calculate your exposure.
Auto Loan Calculator: Total Cost of a Car Loan Including Interest
A $35,000 car at 7.5% over 72 months costs $43,344 total. The extra $8,344 is pure interest. Stretching to 84 months at the same rate costs $9,844 in interest. Here is the full breakdown.
Asset Allocation by Age Calculator: The Right Stock/Bond Mix
The old rule was 100 minus your age in stocks. At 40, that means 60% stocks. Today most advisors use 110 or 120 minus age. Meaning 80% stocks at 40. Here is the full framework and how to choose your allocation.
BRRRR Method Calculator: How Real Estate Investors Recycle the Same Capital
Buy a $120,000 distressed property, spend $40,000 on rehab, refinance at $200,000 value and pull out $140,000. Recovering more than you put in. Then repeat. Here is how the BRRRR numbers work.
CalcMoney vs NerdWallet 2025: 7 Advanced Features for HNW Investors
NerdWallet works for credit cards and score monitoring. For a Roth conversion at 60, a FIRE number on $1.8M, or a mortgage with your state's actual property tax rate, you need something else. Here is what we found.
APR vs Interest Rate: What's the Actual Difference on Your Loan?
Two lenders quote a 6.75% rate on a $400,000 mortgage. Lender A's APR is 6.89%, Lender B's is 7.12%. Over 30 years, that APR gap means Lender B costs $14,400 more. Here is how to read the real number.
401k Early Withdrawal Calculator: The True Cost of Cashing Out
A $30,000 early 401k withdrawal at age 35 in the 22% tax bracket costs $9,000 in taxes plus a $3,000 penalty. But the real cost is the $200,000+ that money would have grown to by retirement.
Budget by Income 2025: Percentages for $500K–$5M Net Worth
The 50/30/20 budget rule breaks down as 50% needs, 30% wants, 20% savings. But the percentages shift as income rises. At $150,000, a 35% savings rate is achievable without sacrifice. Here is how to calibrate your budget.
Car Lease vs Buy Calculator: Which Option Actually Costs Less?
Leasing a $40,000 car for 3 years costs $16,200 in payments with nothing to show at the end. Buying and selling after 3 years costs $23,668 net. Buying and keeping 10 years costs $3,200-$4,000/year. Here is the full comparison.
Backdoor Roth IRA Calculator: How High Earners Access Roth Benefits
Earning over $165,000 as a single filer means you cannot contribute directly to a Roth IRA. The backdoor method lets you do it anyway. Here is the exact two-step process and what it costs.
Cap Rate Calculator: The One Number That Tells You If a Rental Property Is Worth Buying
A property with a 7% cap rate returns $7 of net operating income for every $100 of value. A 4% cap rate property is priced for appreciation, not income. Here is how to calculate cap rate and what it tells you.
Bonus Tax Calculator: Why Your $10,000 Bonus Only Puts $6,500 in Your Account
Bonuses are withheld at 22% federal plus FICA plus state. A $10,000 bonus with 22% federal + 6.2% Social Security + 1.45% Medicare + 5% state = $3,465 in taxes. Here is the full breakdown.
Balance Transfer Calculator: Is a 0% APR Offer Actually Worth It?
A 0% balance transfer on $8,000 in credit card debt saves $1,860 in interest over 18 months. But the 3% transfer fee is $240. Here is how to calculate whether the deal makes sense.
401k Contribution Limit Calculator: How to Max Out and What It Saves You
Maxing your 401k at $23,500 on a $100,000 salary saves $4,712 in federal taxes this year, plus roughly $1,175 in state taxes at 5%. Over 30 years, the tax-deferred compounding produces significantly stronger after-tax returns than a taxable account. Here is the full math.
529 vs Roth IRA for College Savings: Which Account Wins?
A 529 gives you state tax deductions upfront. A Roth IRA gives you flexibility if your kid does not go to college. For most families the answer depends on whether you have maxed your own retirement first.
Barista FIRE Calculator: The Math Behind Semi-Retirement
Barista FIRE means working part-time to cover basic expenses while your portfolio covers the rest. With $800,000 invested and $20,000 in part-time income, you can retire 8 years earlier than full FIRE.
The 4% Rule Explained: Is It Safe for Retirement?
The number one fear of retirees is outliving their money. How do you know how much you can spend from your portfolio without going broke at age 85? Enter the 4% Rule.
How to Calculate Payoff Timeline Across Multiple Loans With Custom Payment Allocation
Most people split extra payments evenly across their debts. That single habit can cost thousands in unnecessary interest. The math behind payment allocation is precise, and running it correctly changes both the timeline and the total cost.
Avalanche vs Snowball: The Debt Payoff Method That Saves More Money
Most people pick a debt payoff method based on feeling, not math. That choice can cost thousands of dollars and add years to their repayment timeline. The numbers between avalanche and snowball are not close.
Debt Payoff vs. Investing: The Math That Decides For You
Most people treat this as a values question. It is a math question. The spread between your debt's interest rate and your expected investment return tells you everything you need to know.
Real Compound Interest: Calculate Your After-Inflation Growth Rate
Most investors track nominal returns and call it progress. Inflation has already eaten a portion of that number. The real compound growth rate tells you what your money actually earned, and it's almost always smaller than you think.
Compound Interest With Monthly Investments: How Much You'll Have in 10, 20, and 30 Years
Most investors underestimate what consistent monthly contributions actually produce over time. The gap between a $300 monthly investment and a $500 monthly investment at 30 years is not $72,000. It's over $200,000. The math is working for you or against you right now.