All Tools — 118 Tools, One Place
Every calculator, converter and generator on HT99 Tools, organized by category. Use the search below to jump straight to what you need.
Finance Calculators
Loans, mortgages, investments, taxes — built with verified formulas from official sources.
Loan Calculator
Calculate monthly loan payments, total interest, and the standard amortization formula.
Open →Mortgage Calculator
Estimate your full PITI monthly mortgage payment including PMI per the Homeowners Protection Act.
Open →EMI Calculator
Calculate Equated Monthly Installment for any loan — works for Indian, Pakistani, and Gulf loans.
Open →Compound Interest Calculator
See how investments grow with the power of compounding — with the standard A = P(1+r/n)^(nt) formula.
Open →Simple Interest Calculator
Calculate simple interest using I = P × r × t — useful for short-term and flat-rate loans.
Open →Savings Goal Calculator
Find out how much to save monthly to reach any financial goal — with future-value math.
Open →Retirement Calculator
Project your retirement corpus with regular contributions using the future-value-of-annuity formula.
Open →ROI Calculator
Measure return on investment as a percentage and an annualized rate using the standard ROI formula.
Open →APR Calculator
Calculate the true Annual Percentage Rate including fees — per Truth in Lending Act / Reg Z.
Open →Auto Loan Calculator
Estimate monthly car payments and total cost of financing a vehicle.
Open →Credit Card Payoff Calculator
Calculate how long it takes to pay off credit card debt and the total interest you will pay.
Open →Income Tax Estimator
Estimate US federal income tax using 2024 IRS brackets (Rev. Proc. 2023-34).
Open →Sales Tax Calculator
Quickly add or extract sales tax from any amount.
Open →Currency Converter
Convert between major world currencies using ECB-sourced rates from the free Frankfurter API.
Open →Inflation Calculator
See how inflation erodes purchasing power over time — nominal vs real value.
Open →Net Worth Calculator
Calculate your net worth by totaling assets minus liabilities.
Open →Health & Fitness
BMI, BMR, calorie, body composition — using CDC, WHO, and peer-reviewed formulas.
BMI Calculator
Calculate Body Mass Index with the CDC formula and WHO classification thresholds.
Open →BMR Calculator
Estimate Basal Metabolic Rate using the Mifflin-St Jeor (1990) formula.
Open →TDEE Calculator
Calculate Total Daily Energy Expenditure (TDEE) — BMR multiplied by an activity factor.
Open →Calorie Calculator
Find your daily calorie target for losing, maintaining, or gaining weight.
Open →Ideal Weight Calculator
Estimate ideal body weight using Devine, Robinson, Hamwi, and Miller formulas.
Open →Body Fat Calculator
Estimate body fat percentage using the U.S. Navy (Hodgdon-Beckett 1984) circumference method.
Open →Water Intake Calculator
Calculate daily water requirement per the IOM/National Academies Adequate Intake.
Open →Pregnancy Due Date Calculator
Estimate your due date using Naegele's Rule (LMP + 280 days) per ACOG.
Open →Ovulation Calculator
Predict your fertile window and ovulation date based on cycle length.
Open →Pregnancy Weight Gain Calculator
Track recommended weight gain per IOM/National Academies 2009 guidelines by pre-pregnancy BMI.
Open →Heart Rate Zone Calculator
Find your target heart rate zones using the Karvonen formula and AHA thresholds.
Open →Macro Calculator
Compute daily protein, carb, and fat targets for your fitness goals.
Open →Math Calculators
Algebra, geometry, statistics — with formulas shown and step-by-step examples.
Percentage Calculator
Solve all percentage problems: X% of Y, X is what % of Y, % change, increase, decrease.
Open →Scientific Calculator
Safe expression evaluator with trigonometry, logarithms, and constants.
Open →Fraction Calculator
Add, subtract, multiply, divide fractions with GCD simplification.
Open →Quadratic Equation Solver
Solve ax²+bx+c=0 — find real or complex roots via the discriminant.
Open →GCD & LCM Calculator
Find greatest common divisor and least common multiple using the Euclidean algorithm.
Open →Prime Factorization
Decompose any integer into its prime factors.
Open →Average Calculator
Compute mean, median, mode, range, and standard deviation in one tool.
Open →Standard Deviation Calculator
Calculate population and sample standard deviation with Bessel's correction.
Open →Ratio Calculator
Simplify ratios, scale them, and solve proportions (A:B = C:D).
Open →Exponent Calculator
Raise any base to any power, including negative and fractional exponents.
Open →Logarithm Calculator
Compute logarithms in any base including natural log using change-of-base formula.
Open →Triangle Calculator
Solve triangles: sides, angles, area (Heron's formula), perimeter, and type detection.
Open →Unit Converters
Length, weight, temperature, data storage, currency — accurate to 8 decimal places.
Length Converter
Convert meters, feet, miles, kilometers — accurate to 8 decimal places.
Open →Weight Converter
Convert kg, pounds, ounces, stones, and tons.
Open →Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine.
Open →Speed Converter
Convert mph, kph, m/s, knots, and feet per second.
Open →Area Converter
Convert square meters, acres, hectares, square feet.
Open →Volume Converter
Convert liters, gallons, cups, milliliters, and cubic units.
Open →Data Storage Converter
Convert bytes, KB, MB, GB, TB, PB — both decimal (1000) and binary (1024) units.
Open →Pressure Converter
Convert pascals, bar, psi, atm, mmHg, and torr.
Open →Angle Converter
Convert degrees, radians, gradians, turns, arcminutes, arcseconds.
Open →Energy Converter
Convert joules, calories, kWh, BTU, ft-lb, and electronvolts.
Open →Time Unit Converter
Convert seconds, minutes, hours, days, weeks, months, years.
Open →Fuel Economy Converter
Convert mpg (US), mpg (UK), km/L, and L/100km.
Open →Text & SEO Tools
Word counters, case converters, readability checkers — privacy-first, runs in browser.
Word Counter
Count words, characters, sentences, paragraphs, and reading time.
Open →Character Counter
Detailed character analysis — with and without spaces, letters, digits, special chars.
Open →Case Converter
Convert text to UPPER, lower, Title, Sentence, camelCase, PascalCase, snake_case, kebab-case.
Open →Text Reverser
Reverse text by characters, words, or lines.
Open →Remove Duplicate Lines
Clean text by removing duplicate lines, keeping first or last occurrence.
Open →Find and Replace Text
Replace text or regex matches across large documents with case options.
Open →Text to URL Slug
Convert any title into a clean SEO-friendly URL slug.
Open →Keyword Density Checker
Analyze keyword density and frequency in any text — for SEO content audits.
Open →Readability Checker
Measure Flesch Reading Ease, Flesch-Kincaid Grade, and Gunning Fog index.
Open →Text Diff Checker
Compare two texts side-by-side and highlight line-by-line differences.
Open →Lorem Ipsum Generator
Generate placeholder text in paragraphs, sentences, or words.
Open →Text-to-Handwriting Style
Display plain text in stylized handwriting fonts (Caveat, Dancing Script, etc.).
Open →Developer Tools
JSON, Base64, regex, JWT, hashes — per IETF RFCs and NIST standards.
JSON Formatter & Validator
Beautify, minify, and validate JSON per RFC 8259. Runs entirely in browser.
Open →JSON to CSV Converter
Convert JSON arrays to downloadable CSV format.
Open →Base64 Encode & Decode
Encode text to Base64 or decode back — per RFC 4648. UTF-8 safe.
Open →URL Encode & Decode
Percent-encode or decode URLs and query parameters.
Open →HTML Entity Encode/Decode
Encode special characters to HTML entities or decode them back, per WHATWG HTML spec.
Open →Hash Generator
Generate SHA-1, SHA-256, SHA-512 hashes using the Web Crypto API (NIST FIPS 180-4).
Open →Regex Tester
Test JavaScript regular expressions with flags, match highlighting, and replacement preview.
Open →HTML Minifier
Compress HTML by removing comments, whitespace, and unnecessary line breaks.
Open →CSS Minifier
Minify CSS by stripping comments and unnecessary whitespace.
Open →JavaScript Minifier
Minify JavaScript by removing whitespace, comments, and unnecessary semicolons.
Open →CSS to Inline Styles
Convert CSS class rules to inline styles — useful for HTML email templates.
Open →JWT Decoder
Decode and inspect JSON Web Token headers and payloads per RFC 7519. Does NOT verify signatures.
Open →ASCII Table Reference
Browse ASCII characters, decimal codes, hex, and HTML entities side-by-side.
Open →Cron Expression Helper
Build and decode cron expressions with human-readable descriptions of each field.
Open →Markdown Preview
Render Markdown to HTML instantly with a live preview pane.
Open →Generators
Password, UUID, QR codes, gradients — using cryptographically secure RNG where it matters.
Password Generator
Create strong, random, secure passwords using crypto.getRandomValues — NIST 800-63B compliant.
Open →UUID Generator
Generate version 4 UUIDs per RFC 4122 — single or bulk mode.
Open →QR Code Generator
Create downloadable QR codes for URLs, text, contact info, and more.
Open →Random Number Generator
Generate random integers within any range, with optional uniqueness.
Open →Random String Generator
Generate random strings for tokens, IDs, and API keys using crypto.getRandomValues.
Open →Barcode Generator
Generate Code 128, EAN-13, UPC-A barcodes as PNG/SVG.
Open →Test Credit Card Generator
Generate valid Luhn-check test card numbers for developer testing only.
Open →Placeholder Image Generator
Generate placeholder images with custom size, color, and text.
Open →CSS Gradient Generator
Design linear, radial, and conic CSS gradients with live preview.
Open →CSS Box Shadow Generator
Create layered box shadows with live preview and copyable CSS code.
Open →Favicon Generator
Generate SVG favicons from a letter and color palette.
Open →Signature Generator
Create a personal handwritten-style signature as text in cursive fonts.
Open →Time & Date
Age, date difference, time zones, countdowns — handles edge cases like leap years.
Age Calculator
Calculate exact age in years, months, days, and total days/hours/minutes.
Open →Date Difference Calculator
Find the number of days, weeks, months between two dates.
Open →Add or Subtract Date
Add or subtract days, weeks, months, or years from any date.
Open →Countdown Timer Maker
Create a live countdown timer to any future date or event.
Open →Time Zone Converter
Convert any time across global time zones using the Intl API.
Open →Weekday Finder
Find the day of the week for any past or future date.
Open →Working Days Calculator
Calculate business days between two dates, excluding weekends.
Open →Leap Year Checker
Check whether any year is a leap year, with the divisibility rules explained.
Open →Color & Design
HEX, RGB, HSL, WCAG contrast — with the exact W3C relative luminance formula.
HEX to RGB Converter
Convert HEX color codes to RGB, HSL, and CMYK with the standard color-space formulas.
Open →Color Picker
Pick any color and copy it in HEX, RGB, HSL, or CMYK format.
Open →Contrast Checker
Verify WCAG 2.2 color contrast ratios using the W3C relative luminance formula.
Open →Color Palette Generator
Generate complementary, analogous, triadic, tetradic, monochromatic palettes.
Open →Gradient Palette Maker
Build harmonious N-step gradients between two colors.
Open →CSS Shadow Preview
Preview and copy layered text and box shadows with live preview.
Open →Image Color Picker
Extract dominant colors from any uploaded image.
Open →Everyday Utilities
Tips, fuel cost, dice, GPA — practical tools for daily life.
Tip Calculator
Calculate tip and split the bill among any number of people.
Open →Percentage Increase Calculator
Calculate percentage increase or decrease between two values.
Open →Random Picker
Pick a random item from your list — great for raffles and decisions.
Open →Dice Roller
Roll dice of any side count — d4, d6, d8, d10, d12, d20, d100.
Open →Coin Flip Simulator
Simulate fair coin tosses for heads or tails decisions.
Open →Fuel Cost Calculator
Estimate fuel expenses for any trip distance and vehicle.
Open →Pizza Order Calculator
Determine how many pizzas to order for any group size.
Open →Paint Calculator
Estimate paint quantity needed to cover any room.
Open →Tile Calculator
Calculate the number of tiles needed for floors and walls.
Open →Time Card Calculator
Track work hours, breaks, and total pay per period.
Open →GPA Calculator
Calculate your grade point average across courses.
Open →PIN Code Generator
Generate secure numeric PIN codes of any length using crypto.getRandomValues.
Open →