DanfioRuns entirely in your browser
No account, no upload, no queue. Sensitive figures such as salary, debt and home price never leave your device, and any page you have opened once keeps working offline.
No signup · No uploads
Free tools that run entirely in your browser
Danfio builds focused tools for the money and file problems people hit every week: mortgage and loan payments, debt payoff plans, mortgage affordability, pay and tax estimates, plus everyday file, text and developer utilities. Each page explains the math it uses, so you can check the answer instead of trusting a black box.
Danfio is a free collection of calculators and practical online tools serving English-speaking users worldwide, with a primary focus on the U.S. — covering money, files, text, and everyday tasks. Every tool runs entirely in your browser, so nothing you enter ever leaves your device.
Formulas shown, not hidden
Every tool documents the formula and the assumptions behind it, with worked examples generated by the same engine that powers the page.
Free, with no signup wall
Calculators, downloaded schedules and copy-ready results are free. When advertising runs, it pays the hosting bill - your data is never sold.
Browse by category
12 categories, 246 tools. Each category page lists every tool in it; the three shown on each card are the ones people usually start with.
Loans & Mortgages
25 toolsPayments, amortization, refinancing and what you can afford.
Debt & Credit
20 toolsPayoff plans, interest cost and credit card minimums.
Income & Payroll
20 toolsTake-home pay, hourly rates, overtime and raises.
Business & Freelance
21 toolsInvoicing, quoting, billable hours and the cost of running a business.
Taxes
20 toolsIncome tax, sales tax, capital gains and after-tax returns.
Investing & Savings
20 toolsCompound growth, retirement targets and savings goals.
Insurance & Benefits
20 toolsLife, auto and home insurance needs plus benefit trade-offs.
PDF & Documents
20 toolsMerge, split, compress and convert files without uploading them.
Developer Tools
20 toolsFormatters, encoders, hashes and generators for everyday work.
Text & Writing
20 toolsCounting, cleaning and transforming text in one click.
Everyday & Health
20 toolsDates, units, BMI and the small math of daily life.
E-commerce & Online Selling
20 toolsMarketplace fees, product margins, ad break-even and inventory math.
Editor's picks
Six pages the site would recommend first, chosen by hand rather than by traffic - nothing here measures what a tool is used for.
Mortgage CalculatorLoans & MortgagesFree mortgage calculator with property tax, insurance, HOA and PMI. See your monthly payment, total interest and a full amortization schedule instantly.Calculate mortgage payments →Paycheck CalculatorIncome & PayrollEstimate your take-home pay from a salary with 2026 federal tax brackets, FICA, state tax and pre-tax deductions, shown per paycheck and per year.Calculate take-home pay →Debt Payoff CalculatorDebt & CreditCompare the debt snowball and avalanche methods on your real balances. See your debt-free date, total interest and the order each debt gets cleared.Plan debt payoff →Loan CalculatorLoans & MortgagesWork out the monthly payment, total interest and full amortization schedule for any fixed-rate loan. Free, instant and computed in your browser.Calculate loan payments →Income Tax CalculatorTaxesSee federal income tax bracket by bracket for 2026, plus FICA and state tax, and what a raise really adds to your tax bill.Estimate income tax →Merge PDFPDF & DocumentsMerge PDF files in your browser: drag two or more PDFs in, keep every page in order and download one combined file. No upload, no account, no watermark.Merge PDFs →
Just added
The six most recently published tools.
Additional Medicare Tax CalculatorIncome & PayrollWork out the 0.9% Additional Medicare Tax: the $200,000, $250,000 and $125,000 thresholds, what an employer withholds and what a joint return adds together.Price the 0.9% Medicare surtax →BMR CalculatorEveryday & HealthEstimate your basal metabolic rate from the Mifflin-St Jeor and Harris-Benedict equations, see the resting burn per hour, and test a five-unit change.Estimate your resting burn →Bonus Tax CalculatorIncome & PayrollSee what is withheld from a 2026 bonus: 22% flat on supplemental wages up to $1,000,000 for the year, 37% above it, and what actually reaches you.See what is withheld from a bonus →Charitable Deduction CalculatorIncome & PayrollSee how much of your 2026 giving is deductible: the 60% cash ceiling, the 50% and 30% property ceilings, the 0.5% floor, the carryforward and the standard deduction.Price your charitable deduction →EITC CalculatorIncome & PayrollPrice the 2026 earned income credit from the IRS table: the maximum for one, two or three children, where the phase-out starts, and the investment income limit.Count your 2026 earned income credit →Macro CalculatorEveryday & HealthTurn a calorie number you already have into grams of protein, carbohydrate and fat, at four common splits or your own percentages, with a per-meal view.Split calories into macros →
Looking for something else?
The full directory lists all 246 tools in one place and can be filtered as you type. If you want the reasoning rather than the arithmetic, the guides explain how the money tools work and where they stop.