Alex Crabinsky
About Alex
Alex Crabinsky is the founder and lead developer of Numeraty. He builds, tests, and reviews every calculator on the platform - over 215 tools covering mortgages, auto loans, credit card debt, investments, tax planning, and more.
Background
With a degree in Computer Science and professional experience in full-stack software engineering, Alex combines technical rigor with a deep interest in personal finance. Before founding Numeraty, he spent years building enterprise software systems, where he developed expertise in data modeling, numerical computation, and user-facing application design.
Approach to Financial Tools
Alex’s philosophy is that good financial tools should be:
- Transparent - every formula, assumption, and default value is documented
- Accurate - outputs are validated against authoritative sources (Federal Reserve data, IRS publications, industry-standard amortization formulas)
- Private - all calculations run client-side in the browser with no data collection
- Accessible - free to use, no signup required, optimized for mobile and desktop
Areas of Expertise
- Mortgage and lending calculations (amortization, APR, points analysis, refinancing break-even)
- Investment and compound interest modeling (retirement projections, portfolio growth, inflation adjustment)
- Debt management strategies (snowball vs. avalanche, payoff optimization, consolidation analysis)
- Tax estimation and planning tools (federal brackets, state-specific rules, payroll tax)
- Statistical and engineering computation (unit conversion, structural analysis, electrical calculations)
Editorial Process
Alex personally reviews every calculator’s formula logic, validates outputs against independent references, and writes or edits the explanatory content accompanying each tool. The platform’s methodology page details the full review and QA process.
Connect
Find Alex on LinkedIn and X (Twitter), or reach out via the contact page.
Guias by Alex Crabinsky
15-Year vs 30-Year Mortgage: Which Is Right for You?
A 15-year mortgage saves you hundreds of thousands in interest but comes with higher monthly payments. Here's how to decide which term fits your finances.
8 min de leitura401(k) vs Roth IRA: Where Should Your Money Go First?
Always capture the full employer 401(k) match before contributing anywhere else -- that's an instant 50-100% return. After that, a Roth IRA beats a 401(k) for most earners under $100,000. Here's the exact order and the math behind it.
8 min de leituraAuto Insurance in 2026: How to Lower Your Premium
Average auto insurance premiums hit $2,150/year in 2026. Here's how coverage works, what actually drives your premium, and which discounts are worth pursuing.
9 min de leituraThe Best Debt Payoff Strategy for Your Situation
Avalanche saves the most money. Snowball delivers the fastest wins. Consolidation simplifies. Balance transfers eliminate interest short-term. The right choice depends on your numbers and your personality.
10 min de leituraBest High-Yield Savings Accounts in 2026: APY Comparison
The FDIC reports the national average savings account rate at 0.41% APY as of early 2026, while leading online high-yield savings accounts are offering 4.0-5.0% APY -- a 10x difference that amounts to $585/year in extra interest on a $13,000 balance. The difference is structural, not temporary.
8 min de leituraBMI vs Body Fat Percentage: Which Actually Matters?
BMI is a height-weight ratio -- it has no idea how much of your weight is fat versus muscle. A 2016 study of 40,420 adults found that 30% of people with a normal BMI had metabolically obese body compositions. Here's how to read both numbers correctly.
8 min de leituraCompound Interest Explained: How Your Money Grows Exponentially
Compound interest earns returns on your returns. A $10,000 investment at 7% becomes $76,000 in 30 years without adding a single dollar. Here's how it works.
7 min de leituraCredit Card Payoff Strategies: How to Eliminate High-Interest Debt
The average American has $6,500 in credit card debt at 22% APR. Here are 5 proven strategies to pay it off faster and save thousands in interest.
8 min de leituraDebt Snowball vs Avalanche Method: Which Pays Off Debt Faster?
The avalanche method saves more money; the snowball method keeps you motivated. Here's how each works and which strategy fits your personality and debt profile.
7 min de leituraHow Much Emergency Fund Do You Really Need?
The Federal Reserve's 2024 SHED survey found that 37% of Americans couldn't cover a $400 emergency from savings alone. The standard 3-to-6-month guideline is a starting point -- your actual target depends on income stability, household structure, and health factors.
8 min de leituraEV vs Gas Car in 2026: True Cost of Ownership Compared
The average EV costs $12,000 more upfront than a comparable gas vehicle in 2026, but fuel and maintenance savings of $2,000-$3,500 per year mean most EV buyers break even in 4-6 years -- before accounting for the $7,500 federal tax credit.
9 min de leituraFHA vs Conventional Loan: Which Mortgage Is Right for You?
FHA loans require just 3.5% down with a 580 credit score. Conventional loans need 3-5% down with 620+ credit. Here's which costs less over the life of the loan.
8 min de leituraFirst-Time Homebuyer Guide 2026: Step-by-Step
Buying your first home in 2026 means navigating 6.75% mortgage rates, elevated prices, and a complex loan landscape. This step-by-step guide covers every stage from credit prep through closing.
12 min de leituraHow Many Calories Should You Eat to Lose Weight?
A 500-calorie daily deficit produces roughly 1 pound of fat loss per week. Your exact target depends on your TDEE -- the total calories you burn each day -- which varies by weight, height, age, and activity level.
8 min de leituraHow Much Car Can I Afford? The 20/4/10 Rule Explained
The 20/4/10 rule says: 20% down, finance for no more than 4 years, and keep total car costs under 10% of gross income. On a $75,000 salary, that limits you to roughly a $28,000 vehicle.
8 min de leituraHow Much House Can I Afford? A Step-by-Step Guide
Use the 28/36 rule: spend no more than 28% of gross income on housing and 36% on total debt. Here's how to calculate your real home buying budget.
8 min de leituraHow Much Life Insurance Do I Need? The DIME Method
The DIME method -- Debt, Income, Mortgage, Education -- gives you a concrete coverage target instead of a vague rule of thumb. Here's how to calculate it for your situation.
9 min de leituraHow Much Paint Do I Need? Room-by-Room Calculator Guide
One gallon of interior paint covers 350-400 square feet in one coat. A standard 12x12 bedroom needs 1.5-2 gallons for walls and ceiling with two coats -- but the actual number depends on color, surface, and whether you prime first.
7 min de leituraHow Much Water Should You Drink Per Day? The Science
The National Academies set total water intake at 3.7 liters (125 oz) per day for men and 2.7 liters (91 oz) for women -- but 20% of that comes from food. Your actual drinking target depends on body weight and activity level, not a fixed 8-glass rule.
7 min de leituraThe 50/30/20 Budget Rule: How to Actually Follow It
The Bureau of Labor Statistics Consumer Expenditure Survey shows the average American household spends 33% of after-tax income on housing alone -- which is why the 50/30/20 rule works for some people but needs adjustment for others. The framework is a starting point, not a fixed rule.
8 min de leituraHow to Calculate Concrete for Any Project: Slabs, Footings, and Posts
Concrete is sold by the cubic yard. A standard 10x10 ft patio at 4 inches thick takes 1.23 cubic yards -- but ordering the right amount requires knowing how slabs, footings, and post holes each get calculated differently.
8 min de leituraHow to Pay Off Student Loans Fast: 7 Strategies That Work
The average student loan borrower takes 20 years to pay off their debt, according to Federal Reserve data, but most could cut that timeline in half with the right strategy. The best approach depends on whether your loans are federal or private.
9 min de leituraLease vs Buy a Car in 2026: The Complete Math
On a $42,000 sedan, leasing runs about $520/month while financing runs $780/month -- but after 5 years you own nothing with a lease. The math depends on how you use a car, not just the monthly payment.
9 min de leituraMortgage Rates in 2026: Current Rates, Forecast, and What to Do
Freddie Mac's Primary Mortgage Market Survey tracks 30-year fixed rates back to 1971 -- the post-pandemic spike to 8% in late 2023 was the highest since 2000. Rates have moderated since, but the path back to sub-4% territory hinges on inflation data and Fed policy decisions that remain uncertain through 2026.
8 min de leituraRenting vs Buying a Home in 2026: The Complete Analysis
With 2026 mortgage rates near 6.75% and national median rent at $1,850/month, the rent-vs-buy equation depends on how long you plan to stay and your local market.
10 min de leituraRetirement Planning by Age: Your Decade-by-Decade Guide
Retirement looks different in your 20s, 40s, and 60s. Here are the specific targets, allocation shifts, and catch-up strategies for each decade -- with real numbers.
11 min de leituraHow Much Should You Have Saved for Retirement by Age?
By 30, aim for 1x your salary saved. By 50, target 6x. By 67, aim for 10x. Here are the benchmarks, the math behind them, and strategies if you're behind.
9 min de leituraRoth IRA vs Traditional IRA: Which Should You Choose?
Roth IRAs offer tax-free growth and withdrawals; Traditional IRAs give you a tax break now. The right choice depends on your current tax bracket and future expectations.
9 min de leituraAre Solar Panels Worth It in 2026? ROI by State
A 10 kW solar system costs $28,000 before the federal tax credit and $19,600 after. In California, that system pays back in 6.2 years and generates $89,000 in savings over 25 years. In Louisiana, payback stretches to 14 years. Location is everything.
9 min de leitura2026 Tax Brackets and Rates: How Much Will You Owe?
The Tax Cuts and Jobs Act of 2017 expires after 2025 unless Congress acts, which could raise the top marginal rate from 37% to 39.6% and eliminate or reduce dozens of provisions affecting most taxpayers. Whether TCJA provisions are extended or expire is the defining tax question of 2026.
8 min de leituraWhen to Refinance Your Mortgage: The Complete Decision Guide
Refinancing makes sense when the interest savings exceed closing costs before you sell. Use the break-even calculation to decide if refinancing is worth it.
7 min de leitura