Conversion Calculator — Free Online Unit Converter

How to Use the Conversion Calculator

1. Select a conversion category: Click the Category dropdown and choose from Temperature, Volume, Data Storage, or Time. Each category contains a comprehensive set of units specific to that measurement type. The From Unit and To Unit dropdowns will automatically update to show only relevant units for your chosen category.
2. Enter the value to convert: Type the numeric value you want to convert into the Value field. The calculator accepts both whole numbers and decimals, so you can enter values like 100, 3.14, or 0.001. There is no upper limit on the value you can enter, making it suitable for both everyday and large-scale conversions.
3. Choose your source and target units: Use the From Unit dropdown to select the unit you are converting from, then use the To Unit dropdown to select the unit you want to convert to. You can swap these at any time to reverse the conversion direction. For example, switching from Celsius to Fahrenheit is as easy as selecting the appropriate units.
4. Read the instant result: The converted value appears immediately in the results panel on the right side of the calculator. The display shows your original value and unit, the converted result with up to six decimal places, and the mathematical formula used for the conversion. Change any input and the result updates in real time.

The calculator retains your last used settings, so you can quickly perform multiple conversions within the same category by simply changing the input value.

Conversion Formulas

Temperature Conversions

Volume Conversions

Volume conversions use liters as the base unit. Each unit has a defined conversion factor to liters. For example, 1 US gallon equals 3.78541 liters, so converting gallons to liters means multiplying by 3.78541. Converting liters to gallons means dividing by 3.78541.

Data Storage Conversions

Data conversions use bytes as the base unit with binary (base-2) scaling: 1 KB = 1,024 bytes, 1 MB = 1,024 KB, 1 GB = 1,024 MB, and so on. Bit-based units convert at 8 bits per byte.

Step-by-Step Example

Convert 72 degrees Fahrenheit to Celsius:

1. Start with the Fahrenheit value: 72
2. Subtract 32: 72 - 32 = 40
3. Multiply by 5/9: 40 x 5/9 = 22.22
4. Result: 72 degrees Fahrenheit = 22.22 degrees Celsius

Room temperature of 72 degrees Fahrenheit is equivalent to 22.22 degrees Celsius. This conversion is one of the most commonly performed temperature calculations worldwide, especially for travelers moving between countries that use different temperature scales.

Practical Examples

Example 1: Sarah's Baking Recipe Conversion

Sarah found a European baking recipe that calls for 250 milliliters of milk, but her measuring cups use US fluid ounces. She uses the conversion calculator to find the equivalent:

• Category: Volume
• From: 250 mL
• To: Fluid Ounces (US)
• Result: 250 mL = 8.45 fl oz

Sarah now knows she needs approximately 8.5 fluid ounces of milk, which is slightly more than one cup. She also converts the oven temperature from 180 degrees Celsius to 356 degrees Fahrenheit, rounding to 350 degrees for her oven dial.

Example 2: Kevin's Cloud Storage Planning

Kevin manages his company's cloud storage and needs to estimate how many gigabytes are left from a 2 TB plan after using 1,350 GB. He also needs to know the total plan size in megabytes for a report:

• Category: Data Storage
• From: 2 TB
• To: GB
• Result: 2 TB = 2,048 GB
• Remaining: 2,048 - 1,350 = 698 GB

Kevin discovers his 2 TB plan actually provides 2,048 GB (not 2,000), giving him 698 GB of remaining space. He then converts to megabytes and reports 2,097,152 MB total capacity. The binary difference of 48 GB between 2,000 and 2,048 represents almost 5% more actual storage than expected.

Example 3: Laura's International Weather Check

Laura is packing for a trip to Berlin and sees the forecast shows temperatures between 8 and 15 degrees Celsius. She needs to know what that means in Fahrenheit to decide which clothes to bring:

• Category: Temperature
• 8 degrees Celsius = 46.4 degrees Fahrenheit
• 15 degrees Celsius = 59.0 degrees Fahrenheit

Laura now understands that Berlin's temperature range of 8 to 15 degrees Celsius corresponds to 46 to 59 degrees Fahrenheit. This tells her she needs a medium-weight jacket and layers. She uses the converter throughout her trip to interpret daily forecasts and decide what to wear each morning.

Example 4: David's Project Time Estimation

David is a freelance developer estimating project duration. His client wants a timeline in weeks, but David tracks time in hours. He has estimated 280 hours of work:

• Category: Time
• From: 280 hours
• To: Weeks
• Result: 280 hours = 1.667 weeks (calendar weeks)
• Working weeks (40 hours): 280 / 40 = 7 work weeks

David notes that 280 hours equals about 1.67 calendar weeks of continuous time, but at a standard 40-hour work week pace, the project will take 7 weeks. He uses the time conversion to also express the estimate as 16,800 minutes and 11.67 days for different reporting formats required by his client.

Conversion Reference Table

Conversion factors are based on internationally recognized standards. Volume uses US customary units. Data uses binary (base-2) prefixes.

Tips and Complete Guide

Understanding Measurement Systems

The world uses two primary measurement systems: the metric system (International System of Units, or SI) and the imperial/US customary system. The metric system, used by most countries, is based on powers of 10, making conversions within the system straightforward (1 kilometer equals 1,000 meters, 1 liter equals 1,000 milliliters). The US customary system, used primarily in the United States, uses less intuitive relationships (1 gallon equals 4 quarts, 1 quart equals 2 pints, 1 pint equals 2 cups). Understanding which system a measurement uses is the first step to accurate conversion. For temperature, most of the world uses Celsius, while the US and a few other countries use Fahrenheit. Scientists universally use Kelvin for absolute temperature measurements.

When Precision Matters

Different applications require different levels of precision. For cooking, rounding to the nearest tablespoon or quarter cup is usually sufficient. For scientific experiments, you may need six or more decimal places. For everyday temperature conversions, rounding to the nearest whole degree is practical. This calculator provides up to six decimal places, allowing you to use as much or as little precision as your situation demands. When performing multiple sequential conversions, try to convert directly between your starting and ending units rather than going through intermediate units, as each step can introduce rounding errors that accumulate. If you need to convert between units not directly supported in one category, consider using a dedicated converter like our mass calculator or speed calculator for specialized conversions.

Data Storage: Binary vs Decimal

One of the most confusing aspects of data storage units is the difference between binary and decimal definitions. Hard drive manufacturers typically use decimal prefixes (1 GB equals 1,000,000,000 bytes), while operating systems use binary prefixes (1 GB equals 1,073,741,824 bytes). This is why a 500 GB hard drive shows approximately 465 GB when connected to a computer. The difference grows with larger sizes: a 1 TB drive shows about 931 GB, and a 2 TB drive shows about 1,863 GB. This calculator uses binary definitions consistent with how computers and operating systems handle data. When purchasing storage, keep this discrepancy in mind to avoid confusion about available capacity.

Common Mistakes to Avoid

• Confusing US and Imperial gallons: A US gallon (3.785 liters) is smaller than an Imperial gallon (4.546 liters). This calculator uses US gallons. If you need Imperial gallons, multiply the US gallon result by 0.832.
• Mixing up bits and bytes: Internet speeds are advertised in megabits per second (Mbps), while file sizes are measured in megabytes (MB). There are 8 bits in 1 byte, so a 100 Mbps connection downloads at about 12.5 MB per second, not 100 MB per second.
• Forgetting temperature offset: Temperature scales have different zero points. You cannot simply multiply to convert between Celsius and Fahrenheit. Always use the complete formula including the addition of 32 (for Celsius to Fahrenheit) or subtraction of 32 (for Fahrenheit to Celsius).
• Assuming months are equal: This calculator defines 1 month as 30 days for standardization, but actual months range from 28 to 31 days. For precise date arithmetic involving specific calendar months, use a dedicated date calculator.
• Using stale conversion factors: While most physical conversion factors are constants, some context-dependent values (like currency or market-based conversions) change over time. Always verify that conversion factors apply to your specific use case.

Frequently Asked Questions