Skip to main content
Build your first Calcs Builder template in about 5 minutes. You’ll create a simple (but complete) calculator based on the Pythagorean theorem—a great way to learn the core workflow: inputs → equations → outputs.
Prefer video? Watch the tutorial, then follow the written steps for the most important details on RefID, Symbol, and units.

​
What you’ll build

A calculator that takes the two short sides of a right triangle (a and b) and returns the hypotenuse (c) using: c = sqrt(a^2 + b^2) By the end, you’ll have a published calculator you can preview and share with your team.

​
Video walkthrough

​
Before you start

  • A Calcs.com account with access to Calcs Builder
  • Any modern browser (Chrome, Firefox, Safari, Edge)
This guide uses meters (m) as an example unit. You can choose different units or leave units blank—just keep them consistent.

​
Key concept: RefID vs Symbol

Calcs Builder uses two identifiers for each widget:
  • RefID: the internal name used in equations (keep it simple: letters/numbers/underscores).
  • Symbol: what shows up in displayed math (can use richer notation for readability).
Rule of thumb: Write equations using RefID, and make things look nice using Symbol.
Current workaround required: In the current version of Calcs Builder you must set both RefID and Symbol for every widget.
For example, if you want the equation display to show c², keep the RefID as c (so other widgets can reference it), and set the Symbol to c (or c with your preferred formatting). Don’t use operator-like text (such as c^2) as a RefID.Calcs Builder variable definition interface showing RefID and Symbol fields

​
Step 1: Open Calcs Builder

1

Sign in

Go to app.calcs.com and log in.
2

Open Calculator Builder

In the main navigation, select Calculator Builder.
3

Create a new calculator

Click Create a new calculator.

​
Step 2: Name your calculator and create a section

1

Fill in basic details

At the top of the editor:
  • Template Name: Pythagoras Calculator
  • Description: Calculate the hypotenuse of a right triangle using the Pythagorean theorem
2

Set a calculator code

Choose a short, unique calculator code such as pythagoras. This is used in URLs and sharing.
3

Add a section for triangle dimensions

Create a section (for example Triangle Dimensions) to keep your inputs and equations organized.

​
Step 3: Add inputs for sides a and b

Add two Input widgets—these are the values users will enter.
1

Add Input: Side a

Click Add Widget → Input, then configure:
  • Label: Side a
  • RefID: a
  • Symbol: a
  • Units: m (or leave blank)
  • Default value: 3
2

Add Input: Side b

Add another Input widget with:
  • Label: Side b
  • RefID: b
  • Symbol: b
  • Units: m (or leave blank)
  • Default value: 4
If you use units, keep both inputs in the same unit system (e.g., both in m). Mixed units can lead to confusing results.

​
Step 4: Add the hypotenuse equation

Now add an Equation widget that computes c.
1

Add the Equation widget

Click Add Widget → Equation (in the same section or a new one).
2

Configure the output variable

Set:
  • Label: Hypotenuse c
  • RefID: c
  • Symbol: c
  • Units: m (or leave blank)
3

Enter the formula

In the formula editor, enter:
If you see errors, confirm that your equation references RefID values exactly (a and b) and that the RefIDs contain no special characters.

​
Step 5: Preview and test

1

Open Preview

Click Preview (top right) to see what users will see.
2

Run a quick test

Enter a = 3 and b = 4. You should get c = 5 (the classic 3–4–5 triangle).
3

Validate with a second test

Try a = 5 and b = 12. You should get c = 13.
Sanity check: If you’re using units and see unexpected results, ensure inputs are lengths (e.g., m) and the output is also a length (not m²).

​
Step 6: Save and publish

1

Confirm your draft is saved

Changes save automatically as you edit. Drafts are only visible to you until published.
2

Publish

Click Save/Publish to share with your team or use it in real projects. Add a short note so others understand what changed.
Once published, you can share the calculator link (based on the calculator code) so teammates can use the tool without editing the template.

​
You’re done 🎉

You built a complete Calcs Builder template using the standard workflow:

​
What to try next

Widget Overview

Learn what each widget type does and when to use it.

Your First Calculation: Area Calculator

Follow a second guided build (length × width).

Common Workflows

See practical patterns used in real templates.

Template Features

Explore advanced options like reports and template settings.
Ideas to extend this template:
  • Add validation (e.g., require positive values)
  • Add a diagram showing where a, b, and c are measured
  • Use lookup tables for standard values (materials, coefficients, etc.)
  • Configure reports for export/print-ready outputs

​
Need help?