Free calculators and browser tools
Seller calculators and practical online tools.
Estimate marketplace fees and profit, or use focused tools for finance, writing, SEO, health and pet care. No signup required.Know your fees. Protect your profit.
Calculate real selling costs across Etsy, eBay, Amazon and Walmart before you list—then price every product with confidence.
EEtsyListing, processing and adseeBayCategory and seller discountsaAmazonFBA, FBM and break-evenWWalmartReferral and optional WFS
Amazon calculator
FBA, FBM and break-even
Fulfillment
Everyday toolkit
More free online tools
Fast, focused calculators and utilities that work directly in your browser—no account or setup required.
WritingConvert Text CaseConvert text case, count words and characters, and remove duplicate lines — all in one free browser tool.Open toolPet careDog Age CalculatorConvert your dog's age to human years using a science-based formula that accounts for breed size.Open toolWritingReading Time CalculatorEstimate how long your article takes to read. Set custom words-per-minute for any audience.Open toolSEOURL Slug GeneratorTurn any title into a clean, SEO-friendly URL slug. Lowercase, hyphenated, and ready to publish.Open toolSecurityPassword GeneratorCreate strong, random passwords with custom length and character options. Secure and browser-only.Open toolMathPercentage CalculatorCalculate percentages instantly — find X% of a number, what percent one number is of another, or percent change.Open toolHealthBMI CalculatorCalculate your Body Mass Index (BMI) using metric or imperial units. See your category instantly.Open toolPet careCat Age CalculatorConvert your cat's age to human years using a veterinary-approved formula.Open toolFinanceMortgage CalculatorEstimate monthly mortgage payments with principal, interest, taxes, insurance, total interest, and loan amount.Open toolFinanceCompound Interest CalculatorProject savings and investment growth with starting amount, monthly contributions, annual return, and timeline.Open toolHealthCalorie CalculatorEstimate daily maintenance calories, BMR, weight loss calories, and weight gain calories using TDEE.Open toolWritingReadability CheckerCheck readability score, grade level, sentence length, complex words, word count, and reading time.Open toolUtilityQR Code GeneratorCreate downloadable QR codes for URLs, plain text, Wi-Fi networks, and email links in your browser.Open tool