Blog
Field notes.
Short reads on the math, formulas, and design decisions behind Calcverse.
- Financial··5 min read
The Real Cost of a Car Loan: Term Length, Rates, and Depreciation
The real cost of a car loan isn't the monthly payment. Here's how 48 to 84-month terms change total interest, plus depreciation, negative equity, and 20/4/10.
Read → - Health··5 min read
How Many Calories Should I Eat to Lose Weight?
How many calories to lose weight: start from TDEE, subtract a sustainable deficit, respect a floor. Worked example, deficit table, and why the math drifts.
Read → - Financial··5 min read
Roth IRA vs Traditional IRA: Which Should You Choose?
Roth IRA vs Traditional IRA comes down to one question: is your tax rate higher now or in retirement? Worked comparison, limits, and when each one wins.
Read → - Auto··5 min read
What Does It Really Cost to Drive a Mile?
The true cost per mile to drive includes fuel, depreciation, insurance, and maintenance. Here's the full calculation, a worked example, and how to cut it.
Read → - Math··4 min read
Median vs Mean: When Averages Lie
Median vs mean explained: why income and house prices always use the median, how one outlier distorts the mean, and which average to use for skewed data.
Read → - Health··4 min read
Resting Heart Rate: What's Normal and What Yours Says About Fitness
What is a normal resting heart rate? The 60-100 bpm range, athlete values, how to measure it correctly, what raises it, and when a reading warrants a doctor visit.
Read → - Construction··4 min read
How to Calculate Square Footage of a Room or House
How to calculate square footage for rooms, L-shapes, and whole houses — including what counts as finished space in a listing, and a full worked example with conversions.
Read → - Financial··5 min read
Amortization Schedule Explained: Reading Your Loan Table
An amortization schedule explained column by column, with a worked first-three-months example on a $300,000 mortgage at 6.5% and how extra payments change the table.
Read → - Math··4 min read
Z-Score Explained: What It Means and How to Calculate It
Z-score explained: the (x - mean) / standard deviation formula, how to read sign and magnitude, a worked test-score example, and a z-score to percentile table.
Read → - Health··5 min read
How Many Steps a Day Do You Really Need? (What Research Says)
How many steps a day do you need? Where 10,000 came from, what research actually shows about the 7,000-8,500 plateau, and steps-to-distance-to-calories math.
Read → - Financial··4 min read
Markup vs Margin: The Difference That Changes Your Prices
Markup vs margin explained: why a 50% markup is only a 33% margin, both conversion formulas, a worked pricing example, and a full markup to margin table.
Read → - Health··5 min read
How Much Water Should You Drink a Day? (Beyond 8 Glasses)
How much water should you drink a day? The 8x8 rule has no real evidence behind it. Here are the actual guidelines, body-weight math, and adjustments.
Read → - Financial··5 min read
Simple vs Compound Interest: The Difference in Real Dollars
Simple vs compound interest explained with both formulas, a $10,000 side-by-side over 20 years, and where each one shows up in real financial products.
Read → - Everyday··4 min read
What Is a Good GPA? (High School, College, and What Employers Check)
What is a good GPA? Here's how the 4.0 scale works, weighted vs unweighted, real averages, honors thresholds, and when GPA stops mattering entirely.
Read → - Math··4 min read
How to Calculate Percentage Increase (and Why Decrease Isn't Symmetric)
How to calculate percentage increase with the (new − old) ÷ old formula, worked examples both ways, and the asymmetry that makes a 50% loss need a 100% gain.
Read → - Health··5 min read
Is BMI Accurate? What It Misses and What to Use Instead
Is BMI accurate? It works for populations and fails for individuals. Here's what BMI misses — muscle, age, ethnicity, fat distribution — and better metrics.
Read → - Financial··5 min read
Debt Snowball vs Avalanche: Which Payoff Method Is Faster?
Debt snowball vs avalanche compared with a worked three-debt example: months to payoff, total interest saved, and how to pick the method you will actually finish.
Read → - Financial··5 min read
How Much Should I Save for Retirement? The 4% Rule and 15% Guideline
How much should you save for retirement? The 25x target, the 4% withdrawal rule, the 15% savings guideline, and age-based milestones with a full worked example.
Read → - Financial··4 min read
Credit Utilization: What It Is and Why 30% Matters
What is a good credit utilization ratio? How to calculate it per card and overall, why under 30% (ideally 10%) matters, and how statement timing changes what gets reported.
Read → - Health··5 min read
How Much Protein Do You Need Per Day? (By Goal and Body Weight)
How to calculate protein intake by body weight and goal: the 0.8 g/kg RDA versus 1.2-2.2 g/kg for active people, a worked example, and per-meal distribution.
Read → - Financial··5 min read
How to Calculate Take-Home Pay from Your Salary
Convert gross salary to take-home pay: federal brackets, FICA (7.65%), state tax, and pre-tax deductions — with a full worked example on a $70k salary.
Read → - Construction··4 min read
How Much Paint Do I Need? Wall Coverage Math
Calculate paint gallons needed: wall area minus doors and windows, ~350 sq ft per gallon, double for two coats — with a worked 12×12 room example.
Read → - Health··5 min read
How Pregnancy Due Dates Are Calculated (Naegele's Rule)
Due dates are estimated from your last period using Naegele's rule (LMP + 280 days). Learn how it works, cycle-length adjustments, and ultrasound accuracy.
Read → - Everyday··5 min read
How to Calculate Hours Worked (With Lunch Breaks & Overtime)
Calculate hours worked correctly: decimal hours, unpaid lunch breaks, weekly overtime at 1.5×, and the 7-minute rounding rule — with a full timecard example.
Read → - Science··4 min read
'Feels Like' Temperature: Wind Chill vs Heat Index Explained
Wind chill measures how cold it feels with wind; heat index how hot with humidity. Learn when each applies, danger thresholds, and why thermometers miss it.
Read → - Financial··4 min read
The Rule of 72: How Fast Will Your Money Double?
The Rule of 72 tells you how many years it takes money to double at a given rate: 72 ÷ rate. Learn why it works, its accuracy, and when to use variants.
Read → - Financial··5 min read
How Much House Can I Afford? The 28/36 Rule Explained
Use the 28/36 rule to estimate how much house you can afford based on income, debts, down payment, and rate — with a worked example and price table.
Read → - Financial··4 min read
APR vs Interest Rate: What's the Difference?
APR includes fees; the interest rate doesn't. Learn why APR is usually higher, when it matters, and how to compare loans with a worked example.
Read → - Health··5 min read
How to Calculate Body Fat Percentage at Home (Navy Method)
Estimate body fat percentage at home with the US Navy tape method — the formula, a worked example, category ranges, and how accurate it really is.
Read → - Math··5 min read
Standard Deviation Explained Simply (With Steps)
Learn what standard deviation measures, calculate it by hand in 5 steps, understand population vs sample, and apply the 68-95-99.7 rule.
Read → - Health··8 min read
BMR vs TDEE: What's the Difference and Which Should You Use?
BMR is what your body burns at complete rest. TDEE adds everything else you do in a day. Here's how they're calculated, when each matters, and how to use them together for weight loss, maintenance, or muscle gain.
Read → - Math··5 min read
Cm to Inches: The Complete Conversion Guide (with History & Formula)
Convert centimeters to inches with the exact 1 in = 2.54 cm ratio, a worked example, a full reference table, and the surprising history behind the international inch.
Read → - Math··5 min read
Kg to Lbs: The Complete Conversion Guide (Formula, Table, History)
Convert kilograms to pounds using the exact 1 lb = 0.45359237 kg definition. Worked examples, a reference table, and where the pound came from.
Read → - Math··5 min read
Celsius to Fahrenheit: Formula, Table, and Why the Scales Disagree
Convert °C to °F with the exact formula F = C × 9/5 + 32. Includes a reference table, common landmarks, and the history of both scales.
Read → - Math··5 min read
Cm to Feet: Height Conversion Explained (Formula and Chart)
Convert centimeters to feet-and-inches for height, using the exact 1 ft = 30.48 cm ratio. Includes a full height chart from 140 cm to 200 cm.
Read → - Math··4 min read
Miles to Km: Formula, Table, and Why the Numbers Look Golden
Convert miles to kilometers using the exact 1 mi = 1.609344 km ratio, with a table, a mental shortcut, and the history of both units.
Read → - Math··4 min read
Meters to Feet: Formula, Table, and Everyday Reference Points
Convert meters to feet with the exact 1 m = 3.28084 ft ratio, a full reference table, and everyday landmarks from ceiling heights to skyscrapers.
Read → - Math··4 min read
Ml to Fl Oz: US and UK Fluid Ounces Explained
Convert milliliters to fluid ounces using the exact US (29.5735 mL) and UK (28.4131 mL) definitions. Table, examples, and why the two ounces differ.
Read → - Math··4 min read
Grams to Ounces: The Cook's Conversion Guide
Convert grams to ounces using the exact 1 oz = 28.3495 g ratio, with a kitchen-focused reference table and the history of the ounce.
Read → - Math··4 min read
Mm to Inches: Precise Conversion for Engineering and Craft
Convert millimeters to inches with the exact 1 in = 25.4 mm ratio, plus a reference table and where mm-precision actually matters.
Read → - Math··4 min read
Liters to Gallons: US vs Imperial, Explained
Convert liters to gallons using the exact US (3.78541 L) and UK imperial (4.54609 L) definitions. Table, examples, and why the two gallons differ by 20%.
Read → - Financial··3 min read
Compound Interest Formula Explained (With Examples)
Learn the compound interest formula A = P(1 + r/n)^nt step by step, with worked examples, a growth table, and common mistakes to avoid.
Read → - Math··3 min read
How to Calculate Percentages: All 3 Types, Step by Step
Master the three percentage problems — X% of Y, X is what % of Y, and percent change — with formulas, examples, and mental math shortcuts.
Read → - Financial··6 min read
How mortgage amortization actually works
Every payment splits between interest and principal. Here's the math, why early payments are mostly interest, and how extra payments change the curve.
Read → - Health··3 min read
How Many Calories Do You Need a Day? The TDEE Method
Estimate your daily calorie needs with the TDEE method: BMR formula, activity multipliers, and how to adjust for losing or gaining weight.
Read → - Health··4 min read
BMI: what it tells you, and what it doesn't
Body Mass Index is a fast screening number, not a diagnosis. Here's how it's calculated and where it breaks down.
Read → - Financial··3 min read
Loan Payment Formula: Calculate Your Monthly Payment
The exact formula behind every loan payment, a worked example, and the three levers — rate, term, principal — that change what you pay.
Read → - Math··5 min read
Converting units without losing precision
Rounding errors add up. Here's how to convert between units — length, mass, temperature — while keeping your numbers honest.
Read → - Construction··3 min read
How Much Concrete Do I Need? Slab & Footing Math
Calculate concrete for slabs, footings, and columns: the volume formula, cubic yard conversion, waste factor, and a bag-count table.
Read → - Everyday··3 min read
How to Calculate GPA on the 4.0 Scale (Step by Step)
Calculate your GPA from letter grades and credit hours: the grade-point table, a worked semester example, cumulative GPA, and weighted vs unweighted.
Read → - Auto··3 min read
How to Calculate Fuel Cost for a Trip (Simple Formula)
Work out exactly what a road trip costs in fuel: the formula, MPG vs L/100km conversion, a worked example, and cost-per-mile budgeting.
Read → - Financial··3 min read
Hourly to Annual Salary: The Conversion That Matters
Convert hourly pay to annual salary (and back) with the 2,080-hour rule, a quick-reference table, and the adjustments for real take-home comparisons.
Read → - Everyday··3 min read
How to Calculate a Discount (and Spot a Fake One)
Calculate sale prices fast: the discount formula, stacked discounts, mental math shortcuts, and how to tell a real markdown from marketing.
Read →