Roof Pitch Calculator
Enter rise and run (or an angle) to get roof pitch, degrees, slope %, and the pitch multiplier. Add your footprint to estimate roofing squares and bundles.
Free calculators that run in your browser
OnlineToolSpot publishes planning tools for home projects and other everyday jobs. The page loads as HTML, the math happens on your device, and the numbers you type are not sent to a server.
Home & DIY
Roof pitch, slope, and other home and DIY calculators. The math runs in your browser, and nothing you type is uploaded.
Concrete Calculator
Enter slab, round pad or post hole sizes to get cubic feet, cubic yards, and how many 40, 60 or 80 lb bags of concrete mix to buy, waste included.
Deck Material Calculator
Turn your deck's length and width into a shopping list: deck boards, linear feet, joists, rim board, screws and posts. Free, no sign-up.
Mulch & Gravel Calculator
Find how much mulch, gravel or stone you need. Enter area and depth to get cubic yards, bag counts and tons, plus how far one yard covers.
Paver Calculator
Estimate how many pavers to buy for a patio or walkway, plus the base gravel in tons and bedding sand in bags. Handles joints and waste.
Paint Calculator
Enter room size, doors, windows and coats to see how many gallons of paint you need for walls and ceiling, in gallons or gallons plus quarts.
Pay & Taxes
Self-employment tax, PTO accrual, salary to hourly, freelance rate, and overtime pay. Each one runs in your browser.
Self-Employment Tax Calculator (2026)
Estimate 2026 self-employment tax on 1099 or Schedule C profit: Social Security, Medicare, the deductible half, and quarterly payments with due dates.
PTO Accrual Calculator
Turn your PTO allowance into hours earned per paycheck or per hour worked, project your balance with a cap, and convert PTO hours to days.
Salary to Hourly Calculator
Convert an annual salary to an hourly wage, or hourly pay to salary, plus daily, weekly, biweekly, semi-monthly and monthly amounts. Gross pay.
Freelance Hourly Rate Calculator
Work backward from the income you want to the hourly and day rate you need to charge, after taxes, expenses, time off and unbilled hours.
Overtime Pay Calculator
Enter your hourly rate and the hours you worked each day to see regular, overtime and double-time pay under federal or California rules.
Mileage Reimbursement Calculator
Turn miles into dollars at the 2026 IRS rates, including the July 1 rate change. Business, medical, moving and charity. Add parking and tolls.
401(k) Employer Match Calculator
Enter your salary, contribution and your employer's match formula to see what the match is worth and how much free money you're leaving behind.
Seller Fees
Marketplace fee and profit calculators for online sellers. The math stays in your browser.
Etsy Fee & Profit Calculator
See every Etsy fee on a US sale: listing, transaction, payment processing and Offsite Ads. Get your payout, profit and the price you need to charge.
eBay Fee Calculator
Calculate eBay fees on a US sale by category, including trading cards and sneakers. See final value fees, payout, profit and the price to charge.
Loans & Debt
Debt-to-income, home affordability, HELOC, and credit card payoff. Each one runs in your browser.
Debt-to-Income (DTI) Ratio Calculator
Calculate your front-end and back-end debt-to-income ratio and see how much more monthly debt fits under 36%, 43% and 50% lender benchmarks.
Home Affordability Calculator
Find a home price that fits your income, debts, down payment and rate. Uses the 28/36 rule by default and includes property tax, insurance and HOA.
HELOC Payment & Borrowing Power Calculator
See how much you can borrow with a HELOC and what you'd pay during the draw and repayment periods. No personal information needed.
Credit Card Payoff Calculator
See how long it takes to pay off a credit card and how much interest you'll pay, or find the monthly payment to be debt-free by a target date.
Rent Affordability Calculator
Find the most rent you can afford by the 30% rule, 50/30/20 and the 40x and 3x income checks landlords use. Enter your income to compare.
Cap Rate Calculator
Build NOI from rent, vacancy and expenses, then see the cap rate, the maximum price at your target cap rate and the NOI you need. Free for rental property.
Auto & Energy
Electricity cost, EV vs gas, and car lease. Each one runs in your browser.
Electricity Cost Calculator
Find what any appliance costs to run per hour, day, month and year. Enter watts (or amps and volts), hours of use and your rate per kWh.
EV Charging Cost vs Gas Calculator
Compare what you'd pay per mile and per year to charge an EV at home or at public fast chargers versus filling up a gas car. Includes charging losses.
Car Lease Calculator
Check a dealer's lease quote line by line: depreciation, rent charge, tax and payment. Handles trade-ins and rebates, and converts money factor to APR.
Auto Loan Refinance Calculator
Compare your car loan with a refinance. See the new payment, interest saved, savings after fees and the month you break even. Free, no sign-up.