UD5 Toolkit
Elephant Toothpaste Demo Calculator - Online Reaction Ratios
Find safe mixing ratios for the classic elephant toothpaste demonstration. Volume adjustments for different container sizes.
Online Calculators - Math & More
99+ toolsCredit Card Payoff Calculator - Online Debt Repayment Plan
Calculate how long it will take to pay off credit card debt with fixed monthly payments or a payoff goal. Understand interest costs fully.
Bayes' Theorem Calculator - Online Probability Update Tool
Easily compute posterior probabilities given prior, likelihood, and marginal likelihood. Visual diagram. All local.
Megapixel Calculator - Online Print Size & Resolution
Find out how large you can print based on image resolution in pixels. Understand DPI and megapixels.
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.
Chemical Equation Balancer - Online Stoichiometry Solver
Enter an unbalanced chemical equation and get the balanced coefficients instantly. Supports parentheses and ions. All local JavaScript algebra.
Compound Interval Calculator - Online Daily/Weekly Growth
Compute compound interest with various compounding frequencies (daily, weekly, monthly). Compare APY with simple interest. Local and secure.
Timecard Calculator - Online Work Hours & Timesheet
Calculate total work hours and pay from time-in/out entries. Supports overtime and breaks. Generate a printable timesheet. All local.
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.
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.
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.
Polygon Area Calculator - Online Irregular Shape Tool
Calculate the area of an irregular polygon by entering its vertex coordinates. Uses the shoelace formula. Pure math.
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.
Loan Calculator - Online EMI & Amortization Schedule Generator
Calculate monthly EMIs for any loan type and see the detailed amortization schedule. Compare different interest rates and tenures with instant results.
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.
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.
Age Calculator - Online Real-Time Age by Date of Birth
Find your exact age in years, months, and days. Calculate the time until your next birthday. All date computations are performed locally and accurately.
Running Splits Calculator - Online Race Pace Predictor
Enter a recent race time and predict times for other distances. Also get lap splits for different intervals.
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.
Confidence Interval Calculator - Online Mean & Proportion
Compute confidence intervals for a population mean (known/unknown sigma) and proportion. All popular Z/T values. Local.
Significant Figures Counter - Online Sig Fig Calculator
Count significant digits in a number and round to a specific number of sig figs. Perfect for chemistry and physics labs.
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.
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.
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.
BMR Calculator - Online Basal Metabolic Rate & Calories
Calculate your Basal Metabolic Rate using the Mifflin‑St Jeor equation. Know how many calories you burn at rest. All data private.
Minutes to Decimal Hours - Online Time Conversion Tool
Convert minutes to decimal hours and vice versa. Essential for billing and payroll. Instant conversion with a handy chart.
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.
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.
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.
Pregnancy Due Date Calculator - Online LMP & Gestation Tool
Estimate the baby's due date based on last menstrual period (LMP) or conception date. Also shows current week and trimester. Educational only.
Activity Calorie Burn Calculator - Online Exercise Estimator
Estimate calories burned for various activities like running, cycling, swimming based on duration and body weight. Informational and motivational.
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.
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.
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.
Blood Alcohol Content Estimator - Online BAC Chart
Roughly estimate your BAC based on weight, gender, drinks consumed, and time. Educational; do not drive.
Candle Making Calculator - Online Wax & Fragrance Ratio
Calculate the exact amount of wax and fragrance oil needed based on container volume and desired scent load. DIY candle crafting.
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.
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.
IQR Calculator - Online Interquartile Range & Box Plot
Enter a dataset to compute Q1, median, Q3, IQR, and highlight outliers. Visual box plot generated in canvas.
Poisson Distribution Calculator - Online Event Occurrence Probability
Compute Poisson probabilities for a given mean rate. Ideal for call centers, traffic analysis. Instant chart.
Dice Roll Probability Calculator - Online Sum & Graph
Select the number and type of dice, then view the exact probability for each possible sum as a bar chart. Great for board game strategy. Local computation.
Image File Size Predictor - Online Estimate Before Export
Input dimensions and color depth to estimate uncompressed file size for BMP, PNG, JPEG. Planning tool.
Carbon Footprint Estimator - Online Simple Lifestyle Check
Answer a few questions about travel, diet, and energy use to estimate your carbon footprint. Awareness tool.
Water Boiling Point at Altitude - Online Tea & Cooking Tool
Enter your elevation and find the exact boiling point of water. Useful for high‑altitude cooking and tea brewing. Local math.
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.
Meeting Cost Calculator - Online Time & Money Waster
Calculate the real monetary cost of a meeting by attendees' hourly rates. A humorous yet insightful productivity tool. All local calculation.
Resistor Color Code Calculator - Online Band to Value
Select color bands to decode a resistor's value, tolerance, and temperature coefficient. Essential for anyone working with electronics hardware.
Voltage Divider Calculator - Online Electronics Resistor Tool
Calculate the output voltage and resistor values for a voltage divider circuit. Includes schematic. Handy for electronics hobbyists and engineers.
Unit Price Calculator - Online Best Buy & Comparison Tool
Calculate the unit price of products to find the best deal. Compare multiple items at once. Perfect for grocery shopping and frugal living.
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.
Probability Calculator - Online Odds & Combinatorics Tool
Compute probability for simple events, as well as permutations and combinations (nPr, nCr). Useful for statistics and game theory. Browser-based math.
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.
Web Image Size Calculator - Online KB & Dimensions Tool
Predict the file size of an image based on pixel dimensions and format (JPEG, PNG, WebP). Rough estimate. Local.
Unix Permissions Calculator - Online chmod Visual Editor
Check read/write/execute boxes and see the octal and symbolic chmod representation. Learn and compute file permissions.
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.
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.
Dice Probability Heatmap - Online Visual Stat Calculator
Visualize the probability distribution of dice rolls as a color‑coded heatmap. For any NdM combination. RPG strategist's dream.
Soap Recipe Calculator - Online Lye & Oil Saponification
Create a custom soap recipe by selecting oils and their percentages. Get precise lye and water amounts. Safety warnings included.
Wind Chill & Heat Index Calculator - Online Feels Like
Enter temperature and wind speed (or humidity) to get the 'feels like' temperature. Safety guidelines included.