Editorial principles
- Every formula and figure is verified against official sources (laws and public agency notices).
- When rates change, the calculator and its guide content are updated together.
- Reported errors are fixed as soon as they are confirmed.
Calculators by Sin Dongho (178)
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Health
Macronutrient Calorie Calculator
Free macronutrient calorie calculator using Atwater factors (4/4/9 kcal/g) per USDA FoodData Central. Convert grams of carbs, protein, fat, and alcohol into calories with percentage split.
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Education
Exam Percentile Calculator
Free exam percentile calculator. Find your percentile from class rank, or convert a raw score to percentile using the mean and standard deviation (z-score / normal distribution).
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Education
Reading Speed Calculator
Free reading speed (WPM) calculator. Measure your words-per-minute by timing a passage, or estimate how long a book will take at your current speed. Average adult reads 200-300 WPM.
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Education
Study Time Planner
Free study time planner. Set your exam date, daily study hours, and per-subject weight percentages — get total study hours, per-subject allocation, and daily breakdown.
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Real Estate
Property Auction Profit Calculator
Free property auction profit calculator. Models foreclosure auctions, sheriff sales, and tax deed auctions. Includes auction premium, inherited liens, rehab budget, and 70% rule check.
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Real Estate
Home Equity Loan & HELOC Calculator
Free HELOC and home equity loan calculator. Compare HELOC (variable rate, Prime+margin), fixed home equity loan, and cash-out refinance. Includes max CLTV (80-85%) and TCJA tax deduction rules.
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Real Estate
LTV Calculator
Calculate your Loan-to-Value ratio instantly to see PMI status, home equity, and how much you can pull in a cash-out refinance under conventional, FHA, and VA limits.
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Taxes
Qualified Dividend Tax Calculator
Calculate federal tax on qualified dividends using the same 0/15/20% LTCG brackets, plus 3.8% NIIT for high earners and state-level dividend tax — full bracket stacking with ordinary income.
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Real Estate
DTI Calculator
Calculate your front-end and back-end Debt-to-Income ratio to see whether you qualify for conventional, FHA, and VA mortgages — and the maximum housing payment each program allows.
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Real Estate
Mortgage Stress Test Calculator
Stress-test your mortgage qualification under rate hikes (+1%, +2%) and income drops (job loss, reduced hours). See worst-case DTI before you sign — not after.
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Real Estate
DSCR Calculator
Calculate the Debt Service Coverage Ratio for any rental property: NOI ÷ debt service. See whether you qualify for non-QM DSCR loans at 1.25+, plus cap rate and gross rent multiplier.
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Taxes
Paycheck Withholding Calculator
Calculate take-home pay using the actual IRS Publication 15-T 2026 percentage method. Federal + FICA + state, W-4 adjustments, 401(k)/health pre-tax, and OBBBA brackets.
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