calcy treasure chest of featuresLove the calculators but not the ads?

Take a sneak peek at the Ad-Free Design being enjoyed by hundreds of members for less than 25¢ a week. Full details and a bonus!

Pythagorean Theorem Calculator to Find Missing Length of Right Triangle

Calculator Preferences
Pythagorean Theorem Calculator Sign
Pythagorean Theorem Calculator

This calculator will find the length of the missing side of a right triangle if the other two side lengths are known. The calculator shows its work and attempts to draw the shape of the calculator based on the results. The Learn tab includes:

  • What is the Pythagorean Theorem?
  • Converse of Pythagorean Theorem
  • Converse Test Calculator
Learn More

Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None
Dec places:Decimal places:Number of decimal places:Number of decimal places to round result to:

Number of decimal places:

Select how many decimal places you would like the result rounded to. Note that you can change the number of places before or after calculating the missing length. Also note that the Pythagorean Theorem Calculator will always display the raw results (out to 14 places) in the steps that will appear beneath the calculator.

Solve for:

Solve for:

Select the right triangle side you wish to solve for.

Length ofLength of Leg a:

Length of 1st Known Length:

Enter the length associated to the label on this line.

Length ofLength of Leg b:

Length of 2nd Known Leg:

Enter the length associated to the label on this line.

Length ofLength ofHypotenuse:

Length of missing side:

This is the missing length of the right triangle.

AreaAreaArea of triangleArea of triangle:

Area of triangle:

This is the area of the right triangle formed by Leg a, Leg b, and Leg c (hypotenuse). The formula used is, Area (K) = 1/2 x b x a.

Sorry, your browser does not support canvas. Please upgrade to the latest version of your web browser software.

If you would like to save the current entries to the secure database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

Feedback AppreciatedFeedback Greatly AppreciatedYour Feedback Would Be Greatly AppreciatedYour Feedback Is Greatly Appreciated


Help and Tools

Help and Tools:

This section, which you can Unstick or Hide in the Calculator Preferences (just above the top of the calculator), contains the following tabs (content too long to fit within bordered frame can be scrolled up and down):

About: Click this tab for an introduction to the calculator.

Instructions: Click this tab for step-by-step instructions for using the calculator.

Terms: Click this tab for a list of the descriptions that are located within each popup help button (info icons).

PCalc: Click this tab for a handy "pocket" calculator you can use when you need to calculate an entry needed for the calculator.

Data: Click this tab to save a set of entries or a note in between visits. Entries and notes will be stored to your web browser's local storage (if supported by your browser of choice), meaning they can only be recalled with the same device and web browser you were using when you saved them. If you'd like to save entries and notes between devices you can do so by subscribing to the Ad-Free Member Version.



Add or remove this page to/from my favorites.

Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.