Small, free tools — and the actual problem each one was built to solve.
Calculates how long a wheelchair or mobility ramp must be for a given rise, so you can build a safe ramp that meets the recommended ADA 1:12 slope ratio.
Find the correct tablecloth size for round, rectangular, oval, or square tables by entering table dimensions and your desired drop length.
Calculates how much soil is needed to fill one or more raised garden beds, helping you buy the right number of soil bags or cubic yards without overordering or coming up short.
Calculates the resistor value and power rating needed to safely connect an LED to a power supply, so you don't burn out the LED or guess the wrong part.
Bakers need to know how much water to add to a given amount of flour to hit a target dough hydration percentage; this calculator converts between flour weight, water weight, and hydration % so the dough isn't too stiff or too sticky.
Pet owners need to convert their cat's age into human years to understand their life stage, health needs, and behavior expectations, but the conversion is not linear and varies by formula.
Calculates the score you need on a final exam to achieve a desired overall grade in a course.
Easily adjust ingredient quantities when scaling a recipe to a different number of servings, preserving the original ratios.
Calculate the alcohol content of homemade beer or wine from original and final gravity readings.
Calculate monthly car loan payments, total interest, and full amortization schedule based on loan amount, interest rate, and term.
Calculates how much water you should drink per day based on your weight and activity level to stay properly hydrated.
Calculate exactly how many cubic yards of concrete you need for a slab, column, or footing to avoid over-ordering or running short.
Quickly convert your dog's age to human years using the updated veterinary formula that accounts for the dog's size (small, medium, large, or giant breed) for a more accurate result than the old 'multiply by 7' rule.
Calculate your estimated one-repetition maximum (1RM) for weightlifting exercises based on the weight you can lift for a set number of reps.
Calculate the precise amount of coffee grounds needed for a given volume of water based on your preferred brew ratio, or vice versa.
Helps assess health risk by calculating the ratio of waist circumference to height, which is a better predictor of cardiovascular and metabolic risks than BMI.
Quickly find the perfect boiling time to get your desired egg doneness – soft, medium, or hard-boiled – based on egg size and whether the eggs are fridge-cold or room temperature.
Generate strong, memorable passphrases using random words, inspired by the XKCD comic, to create passwords that are easy to remember and hard to crack.
Calculate the exact number of days between two calendar dates for planning, billing, or scheduling.
Convert oven temperatures between Fahrenheit, Celsius, and gas mark settings used in international recipes.
Calculates overtime pay at time-and-a-half (1.5x) based on hourly wage and regular vs. overtime hours, helping employees and employers quickly determine total earnings including overtime.
Calculate how much an investment will grow over time with compound interest, or determine the total cost of a loan with compounding.
Estimating the cost to charge an electric vehicle at home based on battery size, current charge level, and local electricity rate.
Converts volume measurements (cups) to weight (grams) for common baking ingredients like flour, sugar, and butter, eliminating guesswork when following recipes.
Estimate your body fat percentage using the US Navy circumference method, requiring only height, neck, waist, and hip measurements.
Calculate your running pace, speed, or finish time for a given distance and time, helping runners plan training and races.
Helps you determine the best bedtime by calculating when you'll complete full 90-minute sleep cycles before a desired wake-up time, reducing grogginess upon waking.
Find the estimated date of conception based on a due date or birth date, helping you understand when pregnancy likely began.
Calculates total hours worked between start and end times, including an optional unpaid break deduction, to quickly determine hours for payroll or time tracking.
Calculates the exact number of weeks and remaining days between any two dates – useful for tracking pregnancy weeks, project timelines, or event countdowns.
Converts numerical digits into their written English word form, so users can spell out amounts for checks, invoices, or legal documents without manual errors.
Quickly calculate the number of working days between two dates, excluding weekends and optionally holidays, for project timeline estimation.