Money · Length · Weight · Volume · Temperature
Conversion Calculators for Currency, Length, Weight, Volume & Temperature
Use this page to find the right conversion tool. You can convert money, lengths, weights, liquid amounts, volume, and temperatures. Start by asking one simple question: What kind of value do I want to convert?
Key idea
Not every conversion works the same way
Many unit conversions use a fixed rule. For example, 1 foot always equals 12 inches.
Other conversions need a different kind of rule. Temperature uses formulas with an extra step, and currency exchange rates can change over time.
How conversions are related
First choose the type of thing you are converting
A foot and a meter both measure length. A pound and a kilogram are used for mass or everyday weight. A gallon and a liter measure volume. Keep the type of quantity the same unless the conversion has extra information, such as density.
Choose your conversion
What do you want to convert?
Pick the card that matches the kind of value you have.
Currency Exchange Rates
Convert one currency into another, such as U.S. dollars to Canadian dollars, euros, or British pounds.
Length & Distance Conversions
Convert inches, feet, yards, miles, millimeters, centimeters, meters, kilometers, and other length units.
Weight & Mass Conversions
Convert pounds, ounces, grams, kilograms, tons, tonnes, and other common mass units.
Volume & Liquid Conversions
Convert liters, milliliters, U.S. gallons, cups, cubic feet, cubic yards, and other volume units.
Temperature Conversions
Convert between Fahrenheit, Celsius, kelvin, and other supported temperature scales.
One important difference
Some conversion rules stay the same. Some do not.
This rule does not change tomorrow, next week, or next year.
Temperature scales have different zero points, so they need a formula instead of one simple multiplier.
The value of one currency compared with another can change over time. The rate date and source matter.
Conversion tools
Find the Conversion That Matches Your Measurement
Choose a tool based on what your number means.
Core concepts & relationships
Understand the measurement before you convert it
A conversion changes how a value is written, but it should still describe the same thing. Before you convert, know what kind of value you have, what unit it uses now, and what unit you want next.
Start here
A conversion changes the unit, not the real amount
One foot and twelve inches are the same length. The number and unit look different, but the real length is unchanged.
Think of a conversion as changing the label used to describe the same amount.
You are not making the object longer, heavier, hotter, or larger. You are showing the same value in a different unit.
Important words
Learn the basic conversion terms
Examples include length, mass, volume, temperature, or money.
Examples include feet, meters, pounds, liters, and degrees Fahrenheit.
If you are changing 5 feet into inches, feet is the source unit.
If you are changing 5 feet into inches, inches is the target unit.
For example, 12 links feet and inches because 1 foot equals 12 inches.
3 feet and 36 inches are equivalent lengths.
Conversion types
Different conversions need different rules
Use a set conversion factor
This is common for length, mass, and many volume units.
Use a formula with an extra step
Fahrenheit and Celsius have different zero points, so multiplying alone is not enough.
The conversion factor changes with dimensions
Square units and cubic units do not use the same factor as simple length units.
Extra information is needed
Changing mass into volume, such as grams to cups, needs density or ingredient information.
The conversion factor can change over time
Currency exchange rates are not fixed. The date, time, and rate source can matter.
Dimensions
Length, area, and volume are different kinds of measurement
Measures one direction.
ft · in · m · kmMeasures a flat surface.
ft² · m²Measures space inside or around something.
ft³ · yd³ · LMass, weight & volume
Similar words can describe different things
Common mass units include grams, kilograms, ounces, and pounds in everyday conversion use.
In everyday speech, people often use “weight” when they really mean a mass measurement.
Common volume units include liters, cups, gallons, cubic feet, and cubic yards.
Easy to confuse
Some unit names sound alike but mean different things
Temperature scales
Temperature needs more than a simple multiplier
Fahrenheit and Celsius use different-sized steps and different zero points.
That is why you cannot convert between them using only one multiplication step.
Currency
Money conversion uses an exchange rate
The rate tells you how much one currency is worth in another.
Formula overview
The main ideas behind common conversions
Used for many length, mass, and volume conversions.
Useful when moving in the opposite direction.
Some temperature conversions need both a scale change and an offset.
Used only when a valid density or ingredient relationship is known.
The exchange rate may change over time.
Compare conversion types
Which kind of rule does each topic use?
| Conversion topic | What it measures | Main rule type | Important detail |
|---|---|---|---|
| Currency | Money | Changing exchange rate | Rate date, source, and fees can matter. |
| Length | Distance | Fixed factor | Do not reuse a length factor unchanged for area. |
| Mass / everyday weight | Mass | Fixed factor | Mass and physical weight are technically different ideas. |
| Volume | Three-dimensional space | Fixed or dimensional factor | U.S. and imperial gallons are different. |
| Temperature | Temperature | Scale factor + offset | Fahrenheit and Celsius have different zero points. |
| Grams to cups | Mass → volume | Density-based | The ingredient or material must be known. |
Concept map
A simple way to choose the right conversion
Formulas, methods & manual calculation
How to do unit conversions by hand
Most conversions follow a short set of steps. First, identify the value and unit you have. Next, choose the unit you want. Then use the correct conversion rule and check that the final unit makes sense.
Universal method
Use these five steps for most conversions
Include the number and its unit.
Decide what unit you want the answer in.
Use a factor, formula, density, or exchange rate.
Keep useful precision while you work.
Make sure the result has the correct unit.
Fixed conversions
Multiply when the factor tells you how many target units fit in one source unit
This works for many length, mass, and volume conversions.
To change feet into inches, multiply by 12.
If you have 5 feet, calculate 5 × 12.
Reverse direction
Divide when you are moving back through the same relationship
If 1 foot equals 12 inches, then inches can be changed back into feet by dividing by 12.
Length & distance
Common length conversion rules
For example, 5 ft 10 in becomes 70 inches before another conversion is made.
Mass / everyday weight
Common mass conversion rules
Volume
Volume measures three-dimensional space
Square & cubic units
Area and volume need powered conversion factors
Temperature
Temperature scales need special formulas
That is why multiplying by 9/5 or 5/9 alone is not enough for a temperature reading.
Cross-type conversions
Mass and volume need extra information
Currency
Currency conversion uses a time-specific exchange rate
Units & symbols
Keep the unit beside the number
| Quantity | Unit | Common symbol | Example |
|---|---|---|---|
| Length | inch | in | 12 in |
| Length | foot | ft | 6 ft |
| Length | centimeter | cm | 25 cm |
| Mass | gram | g | 500 g |
| Mass | kilogram | kg | 20 kg |
| Mass | pound | lb | 50 lb |
| Volume | liter | L | 2 L |
| Volume | milliliter | mL | 250 mL |
| Volume | cubic foot | ft³ | 8 ft³ |
| Temperature | degree Fahrenheit | °F | 68°F |
| Temperature | degree Celsius | °C | 20°C |
| Temperature | kelvin | K | 293.15 K |
Check your work
Use the reverse conversion to test your answer
If the reverse calculation returns the starting value, that is a good sign that the direction and factor were used correctly.
Edge cases
Check for cases that need extra care
For fixed proportional conversions, 0 of one unit is 0 of the other unit.
Negative Fahrenheit and Celsius values are normal. Physical absolute temperature cannot go below absolute zero.
Mass and volume need extra information if you want to move between them.
“Gallon” may mean U.S. or imperial. “Ounce” may mean mass or fluid volume.
Today’s rate should not silently replace a historical rate.
Scientific notation may be useful when numbers become very large or very small.
Precision & rounding
Calculate first, round at the end
Do not cut off useful digits too early.
Everyday measurements often need fewer decimals than scientific work.
The final money amount may use cents, while an exchange rate may need more decimal places.
Final manual check
Before you trust the result
I wrote the starting unit.
I chose the correct target unit.
I used the right type of conversion.
I did not confuse length, area, volume, or mass.
I checked whether a gallon or ounce needed a more exact label.
I rounded only after the main calculation.
I included the unit in the final answer.
Worked examples & practical applications
See common conversions worked out step by step
Each example starts with a value, shows the correct rule, puts the numbers into the rule, and then explains the answer in plain English.
Convert 6 feet to inches
This is a fixed conversion because 1 foot always equals 12 inches.
The length did not change. It is simply written in inches instead of feet.
Convert 50 centimeters to inches
Because 1 inch equals exactly 2.54 centimeters, divide centimeters by 2.54.
The exact calculation gives more digits. For an everyday measurement, two decimal places may be enough.
Convert 20 kilograms to pounds
Use the kilogram-to-pound conversion factor.
In everyday use, this is usually described as a weight conversion, even though kilograms and pounds are being used here as mass units.
Convert 2,500 milliliters to liters
One liter contains 1,000 milliliters.
This is the same amount of liquid written using a larger unit.
Convert 81 cubic feet to cubic yards
This is a volume conversion. One cubic yard equals 27 cubic feet.
The factor is 27 because volume uses three dimensions: 3 × 3 × 3 = 27.
Convert 20°C to Fahrenheit
Celsius and Fahrenheit have different zero points, so this conversion needs both multiplication and addition.
Multiplying by 9/5 alone would be wrong because the Fahrenheit zero point is different.
Use density to change mass into volume
This example uses a made-up material density only to show the method. Real density must come from a reliable source for the actual material.
If the material had a different density, the answer would also be different. This is why grams cannot be changed into cups or milliliters with one universal factor.
Convert money using a stated exchange rate
The rate below is an example rate used only to show the math. It is not presented as a current exchange rate.
A real conversion should also show the rate date, rate source, and any fees or spread that affect the final amount received.
Check your work
Reverse the conversion when possible
The reverse result matches the starting value, so the conversion direction and factor were used correctly.
Practical applications
Where these conversions are useful
| Situation | What you may need to convert | Useful conversion topic |
|---|---|---|
| Measuring a person’s height | Feet and inches ↔ centimeters | Length & Distance |
| Reading product dimensions | Inches ↔ centimeters | Length & Distance |
| Shipping an item | Pounds ↔ kilograms | Weight & Mass |
| Measuring a drink | Milliliters ↔ liters or cups | Volume & Liquid |
| Construction or landscaping | Cubic feet ↔ cubic yards | Volume & Liquid |
| Reading international weather | Celsius ↔ Fahrenheit | Temperature |
| Cooking with mass and volume | Grams → cups with ingredient data | Volume & Liquid |
| Travel or international shopping | USD ↔ another currency | Currency Exchange Rates |
Read the result
A good conversion answer shows more than one number
Example: 20 kg
Example: pounds
Example: multiply by 2.2046226218
Example: 44.09 lb
Example: rounded to two decimal places
Example: exchange-rate date or material density
Reusable workflow
Use the same thinking each time
Tool selection & related converters
Which conversion tool should you use?
Start with the kind of value you have. Money, length, mass, volume, and temperature each have their own conversion rules and their own tool.
Quick decision guide
Pick the tool that matches your value
Use this for USD, CAD, GBP, EUR, and other currencies.
Example: USD → CAD Length Length & distance converterUse this for inches, feet, yards, miles, centimeters, meters, and kilometers.
Example: ft → cm Mass / everyday weight Mass & weight converterUse this for pounds, ounces, grams, kilograms, tons, and tonnes.
Example: kg → lb Volume Volume & liquid converterUse this for liters, milliliters, gallons, cups, and cubic units.
Example: mL → L Temperature Temperature converterUse this for Fahrenheit, Celsius, kelvin, and other supported temperature scales.
Example: °C → °FMatch your question
Choose by what you are trying to find
| Your question | Conversion type | Use this tool |
|---|---|---|
| How much is one currency worth in another? | Currency | Global Currency & Exchange Rate Converter |
| How many inches are in these centimeters? | Length | Length & Distance Conversion Tool |
| How many centimeters are in these feet? | Length | Length & Distance Conversion Tool |
| How many pounds is this value in kilograms? | Mass | Mass & Weight Conversion Tool |
| How many kilograms is this value in pounds? | Mass | Mass & Weight Conversion Tool |
| How many liters are in this amount? | Volume | Volume & Liquid Measurement Converter |
| How many cubic yards are in these cubic feet? | Volume | Volume & Liquid Measurement Converter |
| What is this Celsius temperature in Fahrenheit? | Temperature | Thermal & Temperature Conversion Tool |
| What is this Fahrenheit temperature in Celsius? | Temperature | Thermal & Temperature Conversion Tool |
Use what you already know
Match the starting unit to the unit you want
Use an exchange-rate converter.
Open currency converterUse the length and distance converter.
Open length converterUse the mass and weight converter.
Open mass converterUse the volume and liquid converter.
Open volume converterUse the temperature converter.
Open temperature converterPrimary conversion tools
Five tools cover the main conversion families
Global Currency & Exchange Rate Converter
Converts money from one currency to another using a stated exchange rate.
Length & Distance Conversion Tool
Converts one-dimensional measurements between metric and U.S. customary units.
Mass & Weight Conversion Tool
Converts common mass measurements, including everyday values often described as weight.
Volume & Liquid Measurement Converter
Converts liquid and cubic measurements between supported units.
Thermal & Temperature Conversion Tool
Converts temperatures between Fahrenheit, Celsius, kelvin, and other supported scales.
Special cases
Some questions need more than a normal unit converter
A gram measures mass. A cup measures volume. The material or ingredient must be known.
Feet measure length. Square feet measure area. You need enough dimensions to calculate the area first.
Square feet measure area. Cubic feet measure volume. Add a depth or height before calculating volume.
Today’s exchange rate should not automatically be used for a historical payment.
Method selection
Know what kind of rule is behind the tool
Learn before converting
Open a topic page for more explanation
Use the right type of tool
A converter cannot solve every measurement problem
A length converter cannot find square footage from one length.
You need depth or height before an area becomes a volume.
Density or material information is needed to move between them.
One is normally a mass unit. The other is a volume unit.
They are different volumes, so choose the correct one.
Fees or a provider’s rate may change the amount received.
Tool type
These are conversion calculators
It does not normally estimate an unknown project amount. Instead, it takes a value you already have and expresses it in another compatible unit.
5 ft → 60 in
20 kg → 44.09 lb
20°C → 68°F
USD → CAD using a stated rate
Still not sure?
Ask what your number means
If it is money, choose currency. If it is a distance, choose length. If it is mass, choose weight and mass. If it measures capacity or three-dimensional space, choose volume. If it is a temperature reading, choose temperature.Common mistakes, limits & FAQ
Avoid the most common conversion mistakes
Most conversion errors happen because the wrong unit, rule, or measurement type is used. A quick check before and after the calculation can prevent many mistakes.
Before you start
Ask these questions first
Length, mass, volume, temperature, money, or something else?
Write the starting unit beside the number.
Make sure the target unit measures the right kind of quantity.
Fixed factor, powered factor, offset, density, or exchange rate?
For example, ingredient density, gallon type, or currency date.
Common mistakes
These errors can give the wrong answer
Check which unit you are starting with and which unit you want.
Square units need the conversion factor squared.
Cubic units need the conversion factor cubed.
They are different volumes, so the result will be different.
Ounces usually measure mass. Fluid ounces measure volume.
Mass and volume are different. Density determines the relationship.
Different ingredients can have different mass-to-volume values.
Celsius and Fahrenheit use different zero points.
Historical conversions should use a rate for the correct date.
The amount received may differ from the simple rate calculation.
A rough measurement does not become exact just because the answer has many decimal places.
Important distinctions
Similar words do not always mean the same thing
Length, area & volume
A unit converter cannot create a missing dimension
Mass & volume
Grams cannot be changed into cups with one universal number
A value such as 200 grams tells you how much mass there is.
A value in cups or milliliters tells you how much space the material takes up.
The density must match the actual material or ingredient.
Temperature
Temperature readings and temperature changes are not the same
The offset matters because the scales have different zero points.
The zero-point offset does not work the same way for a difference between two temperatures.
Currency
Currency results depend on the rate being used
It may not be the exact rate offered to a customer.
A bank, card, or transfer provider may use its own rate.
A service may charge a set amount for the transaction.
A fee may be based on the amount being exchanged.
Exchange rates can move, so the timestamp should be clear.
Do not silently replace an old rate with today’s rate.
Precision & rounding
More decimal places do not always mean a better answer
A height or simple room measurement may only need one or two decimal places.
The result should match the quality of the measurements used.
A money amount may show cents while the exchange rate uses more decimal places.
Check the result
Use this short checklist before accepting the answer
The starting value has a unit.
The target unit measures the correct kind of quantity.
The conversion direction is correct.
Square or cubic units use the correct powered factor.
U.S. and imperial units are clearly identified where needed.
Mass-to-volume conversions use a valid density or ingredient.
Temperature formulas include the correct offset.
Currency results use the intended rate and date.
The final answer has been rounded sensibly.
Frequently asked questions
Common questions about conversions
What is a unit conversion?
A unit conversion changes how a measurement is written without changing the real amount. For example, 1 foot and 12 inches are the same length.
How do I know whether to multiply or divide?
Look at the conversion relationship and the direction you are moving. For example, feet to inches uses ×12, while inches to feet uses ÷12.
Why can I not use the same factor for feet and square feet?
Feet measure one dimension, but square feet measure two. Because of this, the length factor must be squared for area.
Why is 1 cubic yard equal to 27 cubic feet?
One yard equals 3 feet. A cubic yard has three dimensions, so the factor becomes 3 × 3 × 3 = 27.
Is a U.S. gallon the same as an imperial gallon?
No. They are different volumes. A converter should clearly say which gallon is being used.
Is an ounce the same as a fluid ounce?
No. An ordinary ounce is usually a mass unit. A fluid ounce is a volume unit.
Can I convert grams directly to cups?
Not with one universal conversion factor. Grams measure mass and cups measure volume. You need the ingredient or its density.
Are grams and milliliters always the same number?
No. Their numerical values may be similar for water under certain conditions, but this does not apply to every material.
Why does Celsius to Fahrenheit need +32?
Celsius and Fahrenheit have different zero points. The +32 is part of the formula that moves between those zero points.
Is kelvin written with a degree symbol?
No. Write 300 K, not 300°K.
Why can a currency conversion result change?
Exchange rates change over time. The rate source, date, time, provider spread, and fees can also affect the final amount.
Can I use today’s exchange rate for an old purchase?
Not if you need a true historical conversion. Use a rate for the correct date when historical data is available.
How many decimal places should I use?
Use enough digits for the job, but do not show more precision than the original measurement supports. Keep extra precision during the calculation and round the final result.
How can I check a conversion?
Reverse the conversion when possible. If you convert 5 feet to 60 inches, then 60 ÷ 12 should return 5 feet.