UD5 Toolkit
Simple Haversine Distance Calculator – Online City‑to‑City
Enter two city names or coordinates and get the straight‑line distance in miles/km. Local calculation.
Tag: Calculator - Basic & Scientific
99+ toolsMegapixel Calculator - Online Print Size & Resolution
Find out how large you can print based on image resolution in pixels. Understand DPI and megapixels.
F‑Stop Calculator - Online Aperture & Depth of Field Reference
Learn about f‑stops and their effect on light and depth. Calculate equivalent exposure adjustments. Educational.
CAGR Calculator - Online Compound Annual Growth Rate
Find the CAGR of an investment given start and end values over a time period. Instant growth rate.
Compound Interest Calculator - Online Investment Growth Tool
Project how your savings and investments grow over time with compound interest. Interactive chart and detailed table. Free and anonymous.
Polygon Centroid Calculator - Online Center of Mass
Find the centroid (center of mass) of any convex polygon by entering vertex coordinates. Useful for physics and design.
TV Viewing Distance Calculator - Online Size vs Resolution Guide
Find the optimal TV size for your room or the best viewing distance based on screen size and resolution (1080p, 4K, 8K). Simple THX/SMPTE reference.
Day of the Week Calculator - Online Find Weekday from Date
Find what day of the week any past or future date falls on. Uses Zeller’s congruence. Fun historical reference tool.
Sales Tax Calculator - Online U.S. State Tax Estimator
Estimate the total price after adding US state sales tax. Select state, enter amount, and see breakdown. Simple and quick, perfect for shoppers.
Mortgage Calculator - Online Home Loan & Amortization Tool
Estimate monthly mortgage payments with amortization schedule. Input loan amount, interest rate, and term. All calculations performed securely on your device.
Battery Series/Parallel Calculator - Online Voltage & Capacity
Combine multiple identical batteries in series and parallel and see the resulting voltage and total capacity. Electronics helper.
Subscription Rename & Cost Calculator - Online Saver
Track your subscriptions, calculate monthly and yearly totals, and find savings by pausing unused services. Local data.
Golden Ratio Calculator - Online Find Balanced Proportions
Enter a number to find its golden ratio long and short segments. Use for pleasing design layouts. Instant.
Fraction Calculator - Online Add Subtract Multiply Divide
Perform arithmetic on fractions and get simplified results. Handles mixed numbers and improper fractions. Step-by-step display. Educational and precise.
Speaker Placement Calculator - Online Home Theater Stereo Angle
Calculate ideal stereo speaker placement (toe-in, distance from wall) for best soundstage. Visual diagram. For audiophiles. Local tool.
Blood Alcohol Content Estimator - Online BAC Calculator
Estimate BAC based on gender, weight, drinks consumed, and time. Uses Widmark formula. Educational tool, never encourage drunk driving. Local only.
Date Duration Calculator - Online Calendar & Workdays
Calculate the exact number of days, weeks, months, and workdays between two dates. Visual calendar highlights. Perfect for projects.
Sample Size Calculator - Online Survey & A/B Test Tool
Determine the minimum sample size needed for a survey or A/B test with a given confidence level and margin of error.
Bayes' Theorem Calculator - Online Probability Update Tool
Easily compute posterior probabilities given prior, likelihood, and marginal likelihood. Visual diagram. All local.
Pythagorean Theorem Calculator - Online Right Triangle Solver
Enter two sides of a right triangle and get the third. Also gives area and perimeter. Simple and visual.
Body Fat Percentage Calculator - Online US Navy & BMI Method
Estimate body fat percentage using the US Navy circumference method or BMI-based formula. Private and instant, all data stays on your device.
Binary Calculator - Online Add Subtract Multiply Binary Numbers
Calculate with binary numbers: addition, subtraction, multiplication, and division. Also bitwise AND, OR, XOR. Programmer's tool, fully client-side.
BMI Calculator - Online Body Mass Index Tool
Check your Body Mass Index using standard or metric units. Get a health category analysis instantly. Educational purpose only; data stays private.
Percentage Calculator - Online Find Percent, Increase & Decrease
Perform common percentage calculations: find percent of a number, percentage increase/decrease, and more. Simple, fast, and always available for free.
Waist‑to‑Hip Ratio Calculator - Online Body Shape Health Indicator
Measure your waist‑to‑hip ratio and learn about associated health risks. WHR interpretation. Educational only.
Day of Year Calculator - Online Ordinal Date
Find out what day number of the year any date is (1‑366). Also shows days remaining. Simple reference.
Moon Age Calculator - Online Days Since New Moon
Calculate the age of the moon in days since the last new moon. See illumination percentage. Simple algorithm.
Confidence Interval Calculator - Online Mean & Proportion
Compute confidence intervals for a population mean (known/unknown sigma) and proportion. All popular Z/T values. Local.
Aspect Ratio Calculator - Online 16:9 4:3 & Custom
Calculate new dimensions while preserving aspect ratio, or find the ratio from width and height. For video and images.
Molar Mass Calculator - Online Molecular Weight Tool
Enter a chemical formula (e.g., H2O, C6H12O6) and calculate its molar mass. Handles parentheses and hydrates. Pure frontend.
Retirement Calculator - Online Savings & Investment Planner
Project your retirement savings growth with monthly contributions, employer match, and CAGR. Interactive chart. Financial data stays on your device.
Hourly Pay Calculator - Online Wage & Overtime Estimator
Calculate your weekly, monthly, or annual pay based on hourly wage and hours. Include overtime rates. Accurate and private.
Tip Pool Calculator - Online Fair Share Splitter for Staff
Fairly distribute pooled tips among staff based on hours worked or points. Customizable percentages. All calculations local and private.
Relative Luminance Calculator - Online WCAG Metrics
Enter a hex color and get its relative luminance per WCAG definition. Understand why this matters for contrast.
Bubble Tea Recipe Calculator - Online DIY Boba Proportions
Choose your cup size and sweetness level, and get exact proportions for tea, milk, syrup, and tapioca pearls. Perfect homemade boba every time.
Run Pace Calculator - Online Min/Mile & Min/Km Splits
Calculate your running pace per mile/km, finish time for a race, and split times. Essential for runners.
Car Loan Calculator - Online Auto Financing & EMI Tool
Estimate monthly car loan payments with trade-in, down payment, and sales tax options. Amortization schedule included. Client-side calculation.
Macronutrient Calculator - Online Protein Carb Fat Split
Determine your ideal daily macronutrient intake based on TDEE, goal, and diet preference. Free nutrition planning tool with local computation.
Discount Calculator - Online Sale Price & Savings Tool
Quickly find the final price after a percentage discount. Also works in reverse to find the original price. Handy for budget shoppers.
Shoelace Length Calculator – Online Eyelet Pairs & Pattern
Enter number of eyelet pairs and lacing style to find the correct shoelace length in inches/cm. Never buy too short.
Popcorn Yield Calculator – Online Kernels to Popped Volume
Enter amount of kernels and see estimated popped volume. Plan movie night snacks perfectly.
Solar Noon Calculator - Online When Is Sun Highest
Enter a location and date to find the exact time of solar noon, sunrise, and sunset. Astronomy tool.
Timezone Difference Calculator - Online Meeting Planner Two Cities
Pick two cities, set a date, and instantly see the time difference. Plan the perfect meeting time across time zones.
Hypergeometric Distribution Calculator - Online Sampler Probability
Calculate probability of k successes when sampling without replacement. Useful for quality control and card games.
Split Payment Calculator - Online Divide Bill with Fees & Tax
Divide a total bill among multiple people considering tax and service fees. See exactly who pays what.
Stock Average Down Calculator - Online Investment Cost Basis
Calculate the new average cost of a stock after buying more shares at a different price. Invest smarter. All local.
Bike Gear Inch & Ratio Calculator - Online Cycling Tool
Calculate gear inches, meters of development, and speed ratio for any chainring/cog combination. For cyclists.
Road Trip ETA Calculator - Online Arrival Time with Stops
Estimate arrival time with driving duration, breaks, and time zone changes. Plan your road trip precisely.
Love Calculator - Online Fun Romance Compatibility Test
Enter two names and get a playful love compatibility percentage. Purely for entertainment! All calculation happens instantly in your browser.
Salary Negotiation Anchor Calculator – Online First Offer Strategy
Based on your target salary, calculates a high anchor number to improve negotiation outcome. Psychological tactic.
Elapsed Time Calculator - Online Duration Between Dates/Times
Enter two date‑time values and get the exact years, months, days, hours, minutes difference. Word output also.
Break‑Even Point Calculator - Online Units & Sales
Calculate the break‑even point in units and dollars. Input fixed costs, variable cost per unit, and price.
Wind Chill & Heat Index Calculator - Online Feels Like
Enter temperature and wind speed (or humidity) to get the 'feels like' temperature. Safety guidelines included.
Transistor Biasing Calculator - Online Fixed & Voltage Divider
Calculate resistor values for transistor fixed bias or voltage divider configuration. Quick quiescent point analysis.
Nernst Equation Calculator - Online Electrochemical Potential
Calculate half-cell and full cell potentials under non-standard conditions. Enter concentrations and temperature. Local.
Gamma Function Calculator - Online Advanced Factorial
Evaluate the Gamma function for real and complex inputs (real part). Extension of factorial. Academic mathematics tool.
Tree Carbon Sequestration Calculator - Online Environmental Tool
Estimate how much CO2 a tree captures over its lifetime based on species, age, and climate. Learn about your green impact. Educational local tool.
Simple Interest Calculator - Online Principal Rate Time Tool
Compute simple interest and final amount given principal, annual rate, and duration. Also reverse-calculates rate or time. Local only.
Unix Timestamp Difference Calculator - Online Durations
Enter two Unix timestamps and get the exact difference in days, hours, minutes, and seconds. Quick time debugging.
Workday Calculator with Holidays - Online Add Business Days
Add N business days to a date, skipping weekends and optionally entering custom holidays. Regional presets.