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Free online calculators
Free online calculators
and tools.
SudoTool is a collection of free, browser-based calculators and tools for home projects, personal finance, and everyday tasks. No account, no installation — just open and get things done.
Featured Tools
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Flooring Calculator
Boxes, square feet, and carpet square yards for laminate, vinyl plank, hardwood, and carpet. Multi-room input, waste factors, and real 12 ft roll math.
Home
Tile Calculator
Tiles, boxes, grout, and trim with NTCA-aligned waste factors (10/15/18/20% by pattern). Subway, hex, large format, mosaic sheets. Imperial and metric.
Home
Paint Coverage Calculator
How many gallons of paint do you need? Accounts for surface texture, finish, coats, doors, windows — with optional cost estimate. 100% in your browser.
Home
Sleep Cycle Calculator
Find the best bedtime or wake time using 90-minute sleep cycles. Live "going to bed now" mode, visual NREM/REM timeline, and CDC age guidelines.
Lifestyle
Rent vs Buy Calculator
See your exact break-even year and the rent threshold where buying wins. Year-by-year net worth table. Save named scenarios locally, no signup.
Finance
Credit Card Payoff Calculator
Compare debt snowball vs avalanche side by side. Up to 5 cards, extra payments, lump sums, and promo APRs. Auto-saves in your browser.
Finance
Auto Loan Calculator
US auto loan payments with state sales tax, trade-in credit, and fees. 50-state tax logic, credit-tier APR presets, side-by-side term comparison, and full amortization.
Finance
Mortgage Calculator
US mortgage payments with PMI, taxes, insurance, and extra payment scenarios. ZIP-based tax auto-fill, full amortization, and screenshot-ready share cards.
Finance
Readability Score Checker
Analyze text readability with 7 algorithms. Visual sentence highlighting, improvement tips, and grade-level targeting. Free and private.
Writing
Why SudoTool?
No signup required
Every tool on SudoTool is available instantly. No account, no email, no password.
Just open your browser and start working.
Built for everyone
Whether you're a software engineer or just need to format a file for the first time,
our tools are designed to be simple and approachable.
Free, always
All tools on SudoTool are completely free to use. We believe useful utilities should
be accessible to everyone, without paywalls.
About SudoTool
SudoTool is a growing collection of free online calculators and tools designed to make everyday tasks easier. Each one is purpose-built to be fast, reliable, and useful — whether you're planning a home project, working out your finances, or just need something done quickly.
We built SudoTool because too many useful tools are hidden behind sign-up walls, ads, or paywalls. Our goal is simple: provide clean, no-nonsense tools that work in any browser, on any device, for anyone.
New tools are added regularly. If you have a suggestion for a tool you'd like to see, feel free to reach out.
From the Blog
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Is It Cheaper to Install Vinyl Plank Flooring Yourself?
Installing vinyl plank yourself skips the labor — about $2,000–4,000 on 1,000 sq ft, since the material costs the same either way. When DIY really saves, and the subfloor mistakes that cost more than you saved.
Do Biweekly Car Payments Actually Save You Money?
Biweekly car payments do save money — but almost all of it comes from one extra payment a year, not the two-week rhythm. On a $30,000 loan at 7% that's about $600 and five months — and you can get it for free.
Is a 72-Month Car Loan Worth It? The Real Cost vs 60 Months
A 72-month car loan trims the payment by about $90/month — but costs $1,600–$2,800+ more in interest and keeps you underwater longer. The real 60-vs-72 math, and the three cases where the longer term makes sense.
Is a Balance Transfer Fee Worth It? The Break-Even Math
A 3–5% fee to move your debt feels like a penalty, but at a 21.5% APR it breaks even in about 2–3 months. The math, a worked table across balances, and when a transfer is not worth it.
When Does a Mortgage Pay More Principal Than Interest?
The famous "18.5 years to pay more principal than interest" rule is really a 6% rule. Here's the tipping point for every rate from 3% to 8% — and why your loan size doesn't change it.
Should You Round Up Your Mortgage Payment?
Rounding up sends every extra dollar to principal — but "the next hundred" can be just $4. On a $300K loan at 6.5%, a steady $100 a month pays it off about 4 years early and saves roughly $61,000.