Free Online Tools
2,638 free online calculators, converters, and tools for finance, health, math, development, and everyday tasks. All tools run in your browser with no signup required.
Financial Calculators (437)
Calculate mortgages, loans, investments, taxes, retirement savings, and more. Make informed financial decisions with accurate calculations for compound interest, amortization schedules, ROI analysis, and budgeting.
- Compound Interest Calculator - Calculate the future value of an investment with compound interest.
- Currency Converter - Real-time exchange rates and currency conversion calculator with high-performance offline caching.
- Loan Calculator - Calculate monthly payments, total interest, and amortization schedule for loans
- Mortgage Calculator - Estimate monthly house payments and see detailed amortization schedules for your loan.
- Paycheck Calculator - Estimate your take-home pay after federal taxes, Social Security, Medicare, and deductions
Math Calculators (312)
Solve mathematical problems from basic arithmetic to advanced calculus. Calculate percentages, fractions, algebra equations, geometry formulas, statistics, and scientific notation with step-by-step explanations.
- °C to °F - Convert Celsius to Fahrenheit instantly.
- °F to °C - Convert Fahrenheit to Celsius instantly.
- 30 60 90 Triangle Calculator - Calculate all sides and angles of a 30-60-90 special right triangle. Enter any side length to find the remaining measurements instantly.
- 45 45 90 Triangle Calculator - Calculate all sides and angles of a 45-45-90 special right triangle. Enter any side length to find the remaining measurements instantly.
- Acreage Calculator - Calculate land area in acres from dimensions in feet, meters, or other units
Health Calculators (114)
Monitor your health with BMI, BMR, body fat, calorie, and fitness calculators. Track pregnancy due dates, ideal weight, heart rate zones, and nutritional needs for better health decisions.
- A1C to Blood Sugar Converter - Convert A1C percentage to estimated average blood glucose (eAG) in mg/dL or mmol/L. Essential tool for diabetes management.
- Adjusted Body Weight Calculator - Calculate ideal and adjusted body weight for dosing decisions using height, sex, and a configurable factor.
- AI Energy Penalty Forecaster - AI-powered tool that input late-night caffeine or alcohol intake and timing. Calculates the exact quantitative impact on tomorrow's deep sleep and baseline energy levels.
- Air Force PT Test Calculator - Estimate Air Force PT scores from run time, push-ups, and sit-ups by age and sex.
- Alcohol Unit Calculator - Calculate alcohol units consumed from drink type, volume, and ABV%. Track against weekly guidelines.
Unit Converters (523)
Convert between units of measurement instantly. Length, weight, temperature, volume, area, speed, time, data storage, and currency conversions with accurate, up-to-date conversion factors.
- 2025 Electricity Cost Calculator - Calculate your electricity costs based on appliance wattage, usage hours, and current 2025 electricity rates. Get accurate monthly and yearly cost estimates.
- 2025 Lighting Energy Cost Calculator - Compare lighting costs between LED, CFL, halogen, and incandescent bulbs. Calculate energy savings and payback periods for switching to efficient lighting.
- 24-Hour to 12-Hour Time Converter - Convert 24-hour military time to 12-hour AM/PM format instantly.
- Abampere Converter - Convert abamperes (electromagnetic CGS units) to amperes, milliamperes, and other electric current units with visual comparisons
- Abcoulomb Converters - Convert abcoulombs (CGS electromagnetic units) to coulombs, statcoulombs, and other charge units with visual comparisons
Developer Tools (91)
Essential tools for software developers. Generate UUIDs, format JSON/SQL, encode/decode Base64, test regex patterns, calculate hashes, and debug JWT tokens.
- .gitignore Generator - Generate comprehensive .gitignore files for any project by selecting your OS, IDE, and languages
- Advanced Case Converter - Developer-focused text transformation. Convert variables between camelCase, snake_case, PascalCase, and more.
- AI Feature Creep Guillotine - AI identifies the 20% of features consuming 80% of your time so you can cut them and actually ship
- AI Token Counter - Count the exact number of tokens in your text for GPT-4, Claude, and Gemini. Essential for developers and AI users to estimate API costs and context window usage accurately.
- AI Tool Cost Comparison Calculator - Compare the real usage costs of ChatGPT, Claude, Gemini, and other AI tools — estimate monthly spend based on your usage patterns and subscription tiers
Everyday Calculators (51)
Practical calculators for daily decisions. Age calculations, date differences, fuel costs, recipe scaling, tip splitting, and household planning tools.
- AI Conflict Triage Decision Tree - AI-powered tool that five specific questions about a grievance to determine if it requires setting a hard boundary, having a conversation, or just letting it go entirely.
- AI Graceful Bow-Out Script Builder - AI-powered tool that generates kind, consequence-free text scripts to decline specific social obligations without burning bridges or sounding flaky.
- AI Hobby Abandonment Predictor - Scores a new hobby idea against upfront costs, physical space requirements, and typical drop-out rates to gauge the risk of wasted money and garage clutter.
- AI Low-Guilt Relationship Maintainer - Input friends and your personal extroversion level. Generates a realistic, sustainable check-in schedule to maintain ties without hitting social burnout.
- AI Memory Valuator - AI-powered tool that predict how memorable a family activity or purchase will be for children, based on developmental psychology.
Text Tools (85)
Transform and analyze text with word counters, case converters, encoders, formatters, and generators. Handle JSON, CSV, markdown, and other text formats efficiently.
- Aesthetic Text Generator - Transform plain text into vaporwave and aesthetic styles using wide-spaced Unicode characters.
- AI Manipulation Highlighter - Paste an ad, sales page, or marketing email. Strips the pitch and highlights the specific psychological triggers (scarcity, manufactured urgency, false authority) being used against you.
- AI Text Message Fallout Predictor - Paste a drafted text message and get an AI analysis of the recipient's likely emotional reaction and any unintentional tones.
- APA Format Generator - Create standardized APA style citations for books and websites instantly.
- Big Text Converter - Convert normal text into large block characters made of ASCII symbols.
Utility Tools (319)
Everyday utilities for common tasks. Generate QR codes, calculate tips, track time zones, create passwords, and solve practical problems quickly.
- 1031 Exchange Calculator - Calculate tax-deferred property exchange requirements and boot amounts
- 24 Hour Timer - Simple and effective countdown timer for tasks, cooking, or workouts.
- 529 vs UTMA Comparison Calculator - Compare 529 plans and UTMA accounts to determine the best education savings strategy
- Abfarad Converter - Convert abfarad (abF) to other capacitance units with visual comparisons
- Abhenry Converters - Convert between abhenrys and other inductance units with visual comparisons
Construction Calculators (174)
Calculate materials, costs, and measurements for building projects. Concrete, lumber, roofing, flooring, paint, and structural engineering calculations.
- 12 Roof Replacement Warning Signs - Interactive checklist to identify warning signs that indicate you need a roof replacement
- 15 Popular Fence Styles - Explore 15 popular fence styles including privacy, picket, split rail, chain link, wrought iron, vinyl, bamboo, composite, cedar, redwood, aluminum, farm/ranch, lattice, shadowbox, and horizontal slat fences with descriptions, pros, cons, and best uses.
- 5 Tricks to Get Rid of Weeds on Your Patio - Learn 5 effective methods to eliminate weeds from your patio, including boiling water, vinegar, salt, polymeric sand, and manual removal techniques.
- Asphalt Calculator - Calculate how much asphalt you need for your driveway, parking lot, or paving project
- Asphalt Driveway Cost Guide - Estimate the cost to install or replace an asphalt driveway based on size, thickness, and local rates
Statistics Calculators (49)
Analyze data with statistical calculators for mean, median, standard deviation, probability, regression, and hypothesis testing. Make data-driven decisions.
- 5-Number Summary Calculator - Calculate the minimum, first quartile, median, third quartile, and maximum for any data set.
- A/B Test Calculator - Determine the statistical significance of your experiments and compare conversion rates.
- A/B Test Significance Calculator - Enter visitors and conversions for two variations to determine statistical significance
- Basic Probability - Calculate the odds and probabilities of independent and dependent events.
- Bayes' Theorem Calculator - Calculate conditional probabilities using Bayes' theorem with step-by-step explanation
Food & Cooking Calculators (26)
Scale recipes, convert cooking measurements, calculate nutritional values, and plan meals. Baking ratios, serving size adjustments, and ingredient substitutions.
- Alcohol Calories Calculator - Calculate the caloric content of alcoholic beverages based on volume and alcohol by volume (ABV).
- Cake Calculator - Calculate cake size and number of servings needed based on number of guests and serving size.
- Calories per Serving - Calculate precisely how many calories are in each portion of your home-cooked meals or recipes.
- Calories to Grams - Convert your daily calorie target into specific macronutrient gram goals based on your preferred percentage split.
- Carbohydrate Calculator - Calculate your optimal daily carbohydrate intake based on body weight, activity level, and training intensity.
Sports Calculators (19)
Track athletic performance with pace calculators, VO2 max estimators, training zone calculators, and sports-specific metrics for running, cycling, and fitness.
- BPM Counter - Tap to the beat to instantly measure Beats Per Minute (BPM) for music or heart rate.
- Calories Burned Cycling - Calculate energy expenditure for cycling workouts based on speed and intensity.
- Calories Burned Running - Estimate total energy expenditure for your run based on distance, weight, and pace.
- Calories Burned Walking - Calculate calories burned while walking by factoring in speed, weight, and terrain incline.
- Cycling Power Calculator - Estimate your cycling power output (Watts) based on speed, weight, climbing grade, and aero position.
Physics Calculators (53)
Solve physics problems with calculators for mechanics, thermodynamics, electricity, optics, and relativity. Calculate force, energy, momentum, and wave properties.
- Acceleration Calculator - Calculate the rate of change of velocity over a specific time interval.
- Angular Acceleration Calculator - Calculate angular acceleration from change in angular velocity over time. Convert between rad/s², degrees/s², and RPM/s.
- Angular Velocity Calculator - Calculate angular velocity in rad/s, RPM, or degrees/s from rotational data or convert between angular velocity units
- Aquarium Glass Thickness Calculator - Calculate the minimum safe glass thickness for a DIY aquarium based on dimensions and safety factor
- Audio Delay to Distance Calculator - Calculate delay in milliseconds for live event delay towers based on distance from stage
Media Tools (52)
Work with images, audio, and video. Resize images, convert formats, generate thumbnails, calculate aspect ratios, and process media files directly in your browser.
- 16:9 TV Dimensions – Screen Size Chart - Reference chart showing width, height, and area for common 16:9 TV screen sizes
- Aspect Ratio Calculator - Calculate missing dimensions while maintaining aspect ratio proportions, or find aspect ratio from dimensions
- Audio File Size Estimator - Estimate file size for audio recordings based on format, bit depth, sample rate, and duration
- Audio Visualizer - Real-time audio visualizations from files or microphone with multiple display modes
- Bio Link Previewer & Simulator - Preview and simulate your link-in-bio page with a mobile phone frame mockup before committing to paid services
Ecology & Environment Calculators (20)
Calculate carbon footprints, energy consumption, water usage, and environmental impact. Tools for sustainable living and ecological awareness.
- Appliance Energy Cost - Estimate the annual operating cost of any household appliance based on its wattage and usage hours.
- Battery Storage Sizing - Calculate the required capacity for an off-grid battery bank based on daily energy needs and autonomy days.
- Carbon Footprint Calculator - Measure your environmental impact by estimating annual CO2 emissions from transport and household energy.
- Carbon Offset Cost - Estimate the cost to neutralize your carbon emissions through certified offset projects.
- CO₂ Emissions Calculator - Calculate specific CO2 output for travel or fuel consumption based on distance and fuel type.
Chemistry Calculators (29)
Calculate molar mass, dilutions, pH levels, stoichiometry, and chemical reactions. Essential tools for chemistry students and professionals.
- Arrhenius Equation Solver - Calculate activation energy or reaction rate constants using the Arrhenius equation.
- Atom Economy Calculator - Measure the efficiency of a chemical reaction by calculating its atom economy percentage.
- Atoms to Moles Calculator - Convert between atoms, molecules, or particles and moles using Avogadro's number
- Dilution Calculator - Calculate the concentration and volume required for dilutions using the C1V1 = C2V2 formula.
- Grams to Moles Calculator - Convert between grams and moles using the molar mass of a substance
Biology Calculators (10)
Biological calculations for genetics, cell biology, ecology, and life sciences. Calculate allele frequencies, population growth, and biological metrics.
- Bacterial Growth Rate - Determine specific growth rate (μ), doubling time, and generation count for bacterial cultures using OD or cell counts.
- Blood Type Calculator - Predict possible blood types of children based on parents' blood types using Punnett square genetics. Show ABO and Rh factor probabilities.
- Cell Doubling Time Calculator - Calculate the generation time and growth rate of your cell culture based on population changes over time.
- Codon Usage Calculator - Analyze DNA/RNA sequences to determine codon frequency, amino acid distribution, and sequence metrics.
- DNA Concentration Calculator - Calculate dsDNA concentration from A260 absorbance and check sample purity with A260/A280 ratios.
Checklists & Planning (225)
Comprehensive checklists for life events, travel, moving, weddings, babies, and more. Never forget important tasks with our curated planning guides.
- Adopting Healthy Habits - Interactive checklist to help you with adopting healthy habits.
- Adult Child Moving Back Home Checklist - Preparation checklist for when an adult child moves back home
- AI Pet Ownership Reality Check - Input a desired pet breed. Outputs the worst-case, unglamorous daily reality (lifetime costs, noise, property damage) to counter the initial emotional pull.
- Airbnb Host Turnaround - Airbnb Host Turnaround - track your progress with this interactive checklist.
- Airport Layover Productivity Checklist - Checklist for making the most of airport layovers with productive work time
Report Generators (13)
Create professional reports and documents. Generate invoices, contracts, summaries, and formatted outputs for business and personal use.
- Break Even Calculator - Determine the exact number of units you need to sell to cover your total costs.
- Cost Benefit Calculator - Evaluate the financial viability of a project by comparing total expected costs against anticipated benefits.
- Customer Churn Rate - Analyze business health by calculating the percentage of customers lost over a specific period.
- Expense Ratio Calculator - Calculate the efficiency of an investment or business operation by comparing expenses to total assets or revenue.
- Financial Ratio Calculator - Quickly assess business health with standard liquidity and leverage ratios.
Photography Calculators (10)
Exposure calculators, depth of field tools, print size calculators, and photography planning tools. Master the technical aspects of photography.
- AI Gear Haul Evaluator - AI-powered tool that input a location, weather, and planned shots. Calculates if lugging heavy, professional equipment is worth the physical effort compared to a minimalist, lightweight setup.
- Crop Factor Calculator - See the full-frame equivalent focal length of a lens on APS-C, Micro Four Thirds, or other sensor sizes
- Depth of Field Calculator - Calculate depth of field, hyperfocal distance, and near/far focus limits for any camera and lens combination.
- Exposure Triangle Calculator - Calculate equivalent exposures by adjusting aperture, shutter speed, and ISO. Find the perfect balance for your shot.
- Flash Guide Number Calculator - Calculate flash exposure using guide numbers. Find the correct aperture, distance, or required flash power for perfect flash photography.
Security Tools (3)
Generate secure passwords, check password strength, and manage authentication-related tasks. Keep your accounts safe with strong security practices.
- Password Generator - Generate strong, random character strings for your accounts.
- Password Strength and Entropy Tester - Analyze password strength with entropy calculation, crack time estimates, and security recommendations
- Password Strength Meter - Evaluate the security level of your passwords with entropy analysis and pattern checking.
Insurance Calculators (14)
Estimate insurance costs, coverage gaps, and policy tradeoffs for home, auto, health, life, and disability decisions.
- Commercial Auto Insurance Estimator - Estimate commercial vehicle insurance costs by vehicle type, use class, radius, driver count, and coverage level.
- Disability Income Gap Planner - Calculate how much disability insurance coverage you need to protect your income if you can't work
- Disability Insurance Gap Analyzer - AI-powered analysis of your disability insurance coverage gaps. Determine how much disability insurance you need based on income, expenses, savings, and existing coverage.
- Earthquake Insurance Calculator - Estimate earthquake insurance premiums and deductibles by state/zone, construction type, foundation, and home value. Show cost-benefit of coverage vs self-insuring.
- Excavation Insurance Class Code Comparator - Compare workers comp and liability insurance premiums across excavation business classifications
Other Tools (9)
Miscellaneous utilities that don't fit elsewhere. Random generators, decision makers, and unique tools for specific needs.
- Coin Flip Simulator - Instantly flip a coin to make fair heads-or-tails decisions with probability tracking.
- Final Grade Calculator - Calculate exactly what score you need on your final exam to reach your target grade.
- Grade Calculator - Calculate your weighted average grade for courses and semesters.
- Guitar Chord Transposer - Transpose guitar chords from one key to another while preserving chord structure, including sharps, flats, and minor chords.
- Quick Random Number - Generate unpredictable numbers for raffles, sampling, or decision making.