# Smart Cost Hub

> Free, fast calculators across construction, finance, health, and math: material and cost estimators, tax and loan tools, BMI and calorie calculators, and everyday math in one hub. No sign-up, instant results.

Free, no-signup calculators across construction, finance, health, and math, plus official 2026 tax data and state-by-state project cost guides. Every tool shows the formula and cites its sources; figures are planning estimates.

## Reference data (free to cite, CC-BY 4.0 with attribution to Smart Cost Hub)
- [2026 federal tax rates](https://www.smartcosthub.com/tax-rates): Official 2026 IRS brackets, standard deductions, SE tax, capital gains, mileage rate, and HSA limits (Rev. Proc. 2025-32).
- [Methodology](https://www.smartcosthub.com/methodology): The formulas and authoritative sources (NRCA, IRS, WHO, Mifflin-St Jeor, U.S. Navy) behind every calculator.
- [Glossary](https://www.smartcosthub.com/glossary): Plain-English definitions of construction, finance, health, and math terms.

## Popular calculators
- [Gutter Calculator](https://www.smartcosthub.com/calculators/gutter-calculator): A typical 1,800–2,200 sq ft single-story home needs about 150–200 linear feet of gutter and one downspout per 30–40 feet (usually 4–6 total).
- [Deck Cost Calculator](https://www.smartcosthub.com/calculators/deck-cost-calculator): A new deck costs roughly $15–$80 per square foot installed — about $4,800–$25,600 for a 320 sq ft deck — depending on pressure-treated, composite, or hardwood material.
- [Roofing Square Calculator](https://www.smartcosthub.com/calculators/roof-square-calculator): Divide your total sloped roof area by 100 to get roofing squares; asphalt shingles come 3 bundles per square, so a 16-square roof needs about 48 bundles plus 5–15% waste.
- [Self-Employment Tax Calculator](https://www.smartcosthub.com/calculators/self-employment-tax-calculator): Self-employment tax is 15.3% of 92.35% of your net profit — 12.4% Social Security (up to $184,500 for 2026) plus 2.9% Medicare — and you deduct half of it on your 1040.
- [Tax Bracket Calculator](https://www.smartcosthub.com/calculators/tax-bracket-calculator): Federal brackets are progressive, so only the income within each bracket is taxed at that rate — your effective rate is always lower than your top (marginal) bracket.
- [1099 vs W-2 Calculator](https://www.smartcosthub.com/calculators/1099-vs-w2-calculator): A fair 1099 rate is usually 1.4–1.6× the equivalent W-2 hourly rate to cover self-employment tax, lost benefits, and unbillable time.
- [Mortgage Payment Calculator](https://www.smartcosthub.com/calculators/mortgage-calculator): Your monthly payment includes principal, interest, property tax, insurance, and PMI; a $320,000 loan at 6.5% over 30 years runs about $2,023/month before taxes and insurance.
- [Compound Interest Calculator](https://www.smartcosthub.com/calculators/compound-interest-calculator): With monthly compounding, $10,000 plus $300/month at 7% grows to about $250,000 in 25 years — and most of that gain is compound growth, not your own contributions.
- [Concrete Calculator](https://www.smartcosthub.com/calculators/concrete-calculator): Concrete is sold by the cubic yard (27 cubic feet). A 10×10 slab at 4 inches thick needs about 1.23 cubic yards, or roughly 56 80-lb bags.
- [BMI Calculator](https://www.smartcosthub.com/calculators/bmi-calculator): BMI is weight (kg) ÷ height (m²): under 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30+ is obese.
- [Calorie Calculator (TDEE)](https://www.smartcosthub.com/calculators/calorie-calculator): Your maintenance calories (TDEE) are your BMR times an activity factor; a 500-calorie daily deficit yields about one pound of fat loss per week.
- [Percentage Calculator](https://www.smartcosthub.com/calculators/percentage-calculator): To find X% of a number, multiply by X/100; to find what percent one number is of another, divide and multiply by 100; for percent change, divide the difference by the original.

## Cost guides (by state)
- [Gutters cost](https://www.smartcosthub.com/cost/gutters): National and per-state 2026 installed cost ranges.
- [Roof replacement cost](https://www.smartcosthub.com/cost/roof-replacement): National and per-state 2026 installed cost ranges.
- [Deck building cost](https://www.smartcosthub.com/cost/deck): National and per-state 2026 installed cost ranges.
- [Siding cost](https://www.smartcosthub.com/cost/siding): National and per-state 2026 installed cost ranges.
- [Fence installation cost](https://www.smartcosthub.com/cost/fence): National and per-state 2026 installed cost ranges.
- [Concrete driveway cost](https://www.smartcosthub.com/cost/concrete-driveway): National and per-state 2026 installed cost ranges.
- [Interior painting cost](https://www.smartcosthub.com/cost/interior-painting): National and per-state 2026 installed cost ranges.
- [Gutter guards cost](https://www.smartcosthub.com/cost/gutter-guards): National and per-state 2026 installed cost ranges.
- [Gutter cleaning cost](https://www.smartcosthub.com/cost/gutter-cleaning): National and per-state 2026 installed cost ranges.
- [Metal roof cost](https://www.smartcosthub.com/cost/metal-roof): National and per-state 2026 installed cost ranges.
- [Tile roof cost](https://www.smartcosthub.com/cost/tile-roof): National and per-state 2026 installed cost ranges.

## Guides & articles
- [How to Calculate a Tip (and Split the Bill)](https://www.smartcosthub.com/articles/how-to-calculate-a-tip): A fast mental method for 15%, 18%, and 20% tips — plus how to split the total across the table.
- [How Many Calories Should You Eat to Lose Weight?](https://www.smartcosthub.com/articles/how-many-calories-to-lose-weight): Find your maintenance calories, then subtract a sensible deficit. A 500-calorie daily cut is about one pound a week.
- [Roth vs. Traditional: Which Retirement Account Wins?](https://www.smartcosthub.com/articles/roth-vs-traditional-which-wins): It comes down to one question: will your tax rate be higher now or in retirement? Here's how to decide.
- [Does a New Roof Pay Off at Resale? Roof Replacement ROI](https://www.smartcosthub.com/articles/does-a-new-roof-pay-off-at-resale): A new asphalt roof recoups about 60% of its cost at resale — but the bigger value is that it often lets the home sell at all.
- [Does New Siding Add Home Value? Siding ROI Explained](https://www.smartcosthub.com/articles/does-new-siding-add-home-value): New siding is one of the highest-return exterior projects — fiber cement recoups roughly 80–88% of its cost at resale.
- [Does a New Deck Add Home Value? Deck ROI in 2026](https://www.smartcosthub.com/articles/does-a-deck-add-home-value): A wood deck recoups about 50–83% of its cost at resale. Here's how material, size, and your market change the return.
- [Metal Roof vs. Asphalt Shingles: Which Is Worth It?](https://www.smartcosthub.com/articles/metal-roof-vs-asphalt-shingles): Metal costs about twice as much upfront but lasts two to three times longer. Here's how to decide based on how long you'll stay.
- [Are Gutter Guards Worth It? Cost vs. Payback in 2026](https://www.smartcosthub.com/articles/are-gutter-guards-worth-it): Gutter guards run about $1,000–$3,500 installed. Here's how to weigh that against years of cleaning bills and water-damage risk.
- [How to Calculate Exact Age in Years, Months, and Days](https://www.smartcosthub.com/articles/calculate-exact-age): Counting age precisely means handling different month lengths and leap years. Here's the method behind it.
- [How to Calculate Percentages (3 Common Cases)](https://www.smartcosthub.com/articles/how-to-calculate-percentages): Find a percentage of a number, figure out what percent one number is of another, or calculate percent change.
- [How to Calculate Your Daily Calorie Needs (TDEE)](https://www.smartcosthub.com/articles/calculate-your-tdee): Your TDEE is the calories you burn in a day. Here's how the Mifflin-St Jeor equation and an activity factor estimate it.
- [BMI vs. Body Fat Percentage: Which Should You Track?](https://www.smartcosthub.com/articles/bmi-vs-body-fat): BMI is a quick screen from height and weight; body fat percentage measures composition. Here's when each is useful.
- [How Self-Employment Tax Works for Freelancers](https://www.smartcosthub.com/articles/how-self-employment-tax-works): Self-employment tax is the 15.3% Social Security and Medicare freelancers pay on their own. Here's how it's calculated.
- [Marginal vs. Effective Tax Rate: What's the Difference?](https://www.smartcosthub.com/articles/marginal-vs-effective-tax-rate): Your marginal rate applies to your next dollar; your effective rate is what you actually pay overall. Here's why they differ.
- [Concrete Basics: Cubic Yards, Bags, and Waste](https://www.smartcosthub.com/articles/concrete-yards-and-bags): Concrete is sold by the cubic yard (27 cubic feet). Here's how to size a pour and decide between bags and ready-mix.
- [How Many Roofing Squares Is Your Roof?](https://www.smartcosthub.com/articles/how-many-roofing-squares): A roofing square is 100 square feet. Here's how to convert your roof's footprint and pitch into squares and shingle bundles.

## Browse by category
- [Construction](https://www.smartcosthub.com/construction): 20 calculators — Material & cost estimators for home exterior projects.
- [Finance](https://www.smartcosthub.com/finance): 27 calculators — Tax, loan & savings tools for freelancers and households.
- [Health](https://www.smartcosthub.com/health): 7 calculators — Body metrics & nutrition calculators.
- [Math & Everyday](https://www.smartcosthub.com/math): 10 calculators — Percentages, dates, tips & other everyday math.

## About
- [About Smart Cost Hub](https://www.smartcosthub.com/about): Editorial standards and the niche-site network behind the data.