The Ultimate Collection of Online Calculators

Agriculture and Horticulture

California Aquaculture Calculations: A database of calculators related to aquaculture.
Acreage Calculator: A simple, handy calculator for measuring acreage.
MG Fertilizer Calculator: A page that calculates the amount and type of fertilizer your soil needs.
Spreader Setting Calculator: A tool that calculates the setting a spreader should be on based on your fertilizer brand.
Turf Spray Calculator: A tool that computes the spray rate of a fertilizer or pesticide, and the amount that should be sprayed for the maximum safety and effectiveness.

Aviation

Distance/Course Calculator: A resource for measuring flight plans.
Time and Distance Calculator: A tool that calculates the distance and the time of a flight.
Flight Route Calculator: A calculator that measures a flight's distance and maps its route.

Automobiles, Trucks, and Motorcycles

The Real Cost of Car Ownership Calculator: A calculator that demonstrates how the cost of a new or used car is higher than its sticker price.
Horsepower Design Equations and Formulas Calculator: A calculator that solves for torque based on power and speed (in revolutions per minute).
Loan Calculator: A handy tool that allows you to estimate your monthly car payment.
Car Depreciation Calculator: A calculator that estimates how much your car is worth right now and how much it will be worth when you plan to sell it.

Automotive Design and Development

Individual Emissions Calculator: A resource that estimates the amount of greenhouse gases your daily travel routine produces.
AAA Fuel Cost Calculator: A tool that allows drivers to get an idea of the fuel cost for a planned trip.
MPG-Calculator: A tool that calculates you your gas mileage and shows how much it is costing you.

Finance

IRS Withholding Calculator: A multi-page calculator that checks whether you have enough U.S. income tax withheld from your paychecks.
Loan Interest Calculator: A tool that helps you figure out how quickly you could repay loans using various payment plans.
Instant Lease Quote Calculator: A resource that helps you figure out what your monthly lease payment would be using various purchase options.
APR Calculator: A tool that calculates the annual percentage rate for any loan.
Mortgage Calculator: A calculator that allows you to estimate your monthly mortgage payment, and therefore the real cost of a home.
Retirement Planner: A resource that helps you keep track of how well you will be funded for retirement.
Retirement Income Calculator: A tool that calculates your monthly income in retirement, based on your financial planning now.
The Salary Calculator: A series of calculators that measure your real salary, take-home pay, and more.
Benefit Calculators: A tool that allows you to estimate your future Social Security benefits.
Section 179 Calculator: An online calculator to determine your small business Section 179 Tax Deduction for equipment, vehicles, and software.
Trust Fund Calculator: A tool that gives the current value of a trust fund.

Gambling

Online Blackjack Calculators: A list of calculators that can improve your odds at blackjack.
Free Exotic Wager Cost Calculator: A tool that gives the cost of an exotic wager at a horse race.
Lottery Odds Calculator: A tool that calculates your real odds in a variety of lottery games.
Poker Odds Calculator: A poker calculator that determines the odds for any given hand in any given poker game.
Slot Machine Simulation: A calculator that simulates a slot machine game and gives the odds for winning.

Cameras

Depth of Field Calculator: A handy resource that photographers can use to measure their depth of field.
Pinhole Calculator: A calculator that lets photographers measure various exposure times, and more.
Field of View Calculator: A tool that calculates the field of view for several Canon and Nikon cameras.
The Massive Dev Chart: An enormous database of development information for black-and-white film, that allows users to contribute data.
Shutter Speed Calculator: An online tool for calculating shutter speed.
SunPosition Calculator: A calculator that allows you to determine the sun's position anywhere at any time of the year.
Time Duration Calculator: A tool that allows you to measure the number of hours and minutes between any two times on a clock.
Time Zone Converter: A calculator that takes the time in one time zone and figures out the time in another.

Electricity

Solar Power Calculator: A tool that measures the size and cost of a solar power project, at your home or at another location.
Simple Wind Turbine Investment Payback Calculator: A calculator that determines how long it will take to recoup an investment in a mini wind turbine.

Clothing and Apparel

Clothing Size Conversion Table: A chart that compares clothing sizes in the United States, the U.K., and Europe.
Clothing Conversions: A database of different online clothing size converters, including resources for shoes, rings, and more.

Health and Nutrition

BMR Calculator : A calculator that estimates how many calories your body burns when you're at rest—i.e., your basal metabolic rate.
Body Fat Calculator: A tool that lets you calculate your body fat percentage.
Calculate Your Body Mass Index: An instrument that helps you determine whether you have a healthy body mass index.
Daily Calorie Needs: A tool that calculates how many calories your body needs every day.
Food Calories & Nutrition Calculator: A tool that calculates how many calories you consume based on the food you eat, including packaged foods.

Music

Scale Tool 1.3: A free downloadable program that allows you to calculate scales and to tune pianos and guitars.
Frequency to Note Calculator: A tool that allows you to determine which notes certain frequencies represent.
Musicalc: A downloadable tool, designed for sound engineers and musicians, that calculates tempo, delay, and frequency.
Music Calculator: A list of several different tools designed to help with tuning and other musical calculations.
IntervalCalc: An interval calculator available in exchange for some original artwork, or for a small fee.

Math

Basic Math Calculator: A simple calculator that performs the basic math functions.
A Simple Logarithm Calculator: A handy tool for calculating simple logarithms.
Square Root Calculator: A tool that will find the square root of any number.
Trigonometry Function Calculator: A calculator that will determine the sine, cosine, tangent, etc. of any angle.
Online Analytical Geometry Calculator: A list of calculators for use in analytical geometry.
Statistics Calculators: Several free statistics calculators.
Calculus Calculators: A database of calculus-related calculators.
Adding Machine Calculator: An online calculator that works just like a physical adding machine.
Paper Tape Calculator 2.3: A free downloadable program that converts calculations into a .txt format.
Online Fraction Calculator: An easy-to-use tool that can add, multiply, subtract, and divide fractions.
Convert Fraction to Decimal Calculator: A tool that can convert fractions into decimals.

Units

Cooking Conversion Calculator: An easy-to-use converter for units of measure commonly used in at-home cooking.
Time Calculator: A tool that can convert hours to minutes, add total times, and more.
Online Distance and Length Converter: A calculator that can change kilometers to miles, and convert many other distance units.
Distance and Length Converter: A calculator that can convert various length units into other units.
Convert Speed: A unit converter for speed measurements.
Weight Converter: A calculator that can convert grams to ounces, kilograms to pounds, and more.
Volume Converter: A tool that can change liters to gallons, and convert other volume units between the metric and imperial measurement systems.

Currencies

Currency Tools: A list of calculators that can convert between different currencies and calculate other charges related to exchanging currencies.
Duty Calculator: A tool that can calculate the cost of importing goods to Europe or exporting goods from Europe.
Export Price Index Calculator: A tool that can determine the export price for a commodity, taking inflation into account.
CPI Inflation Calculator: A tool that can calculate how the value of the dollar has changed from one specific year to another because of inflation.
Cost-of-Living Calculator: A tool that is able to compare cost-of-living statistics from many different U.S. cities, and to calculate the salary change that should accompany a move from one city to another.
Compound Interest Calculator: A calculator that demonstrates how savings can grow over time.

About the Author :

Written by Chris Fletcher (aka the Lease Guy). Chris is a senior account executive at Crest Capital, where he manages vendor finance programs for manufacturers and dealers of equipment, vehicles, and software. He's also an active Twitterer—check out his page if you follow financial topics and current events in the world of finance.