Calculators and web forms builder for the site
We help you create online calculators of any complexity, without a designer or programmer
177 485+
Forms created
Built by teams and solo creators worldwide
8 155 399+
Submissions processed
Handled securely with automated delivery
1 035 527+
Monthly form views
forms per month
4.9 / 5.0
Customer rating
Verified across independent reviews
What the calculator builder does
A calculator is built in the same builder: calculation fields, formulas and a total before submit. You do not need a separate service or a developer.
How to build a calculator
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Fields and formulas
Formulas and calculation fields are assembled in the builder. The person sees the total before they submit. You do not write code.
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Logic picks the branch
Conditions show the fields and pages that apply. The person does not fill in parameters meant for someone else.
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The total on the form
After the calculation the amount is visible. You can pass it to the payment terminal or keep it on the submission.
What a calculator includes
Calculation fields
Formulas are written in calculation fields of the same builder. You do not need a separate script or a spreadsheet.
Logic
Show only the required fields and pages of the form, depending on customer responses
Pay the calculated amount
The amount from a calculation field can go to the payment terminal. Payment stays in the same form.
Exchange rates
Supports online exchange rates in price formulas
Rules for redirections
Redirect the user to different pages, depending on their responses, after the online calculation
Appearance
Customize different themes for calculators, according to the design of your site
Design and brand
- Themes Customize different form themes to match your website design
- Your own CSS You can add your own CSS and match the form to the site.
- Subdomain The form opens on a direct link at your subdomain.
You can run a calculator from code and from AI clients
The REST API creates and updates forms from your app. MCP connects Claude, Cursor and other AI clients: the calculator is built in the chat.
REST API
A machine-readable description of the REST API.
Native MCP
Remote MCP server for Claude, Cursor and other AI clients — create forms, edit fields and view submissions using natural language.
Place the form on your site
On a direct link on our site
Share the form link. No extra page needed.
Inside the page on your site
Embed the form in the page, without a developer.
As a pop-up window
Open on a click, a trigger, or a sticky tab.
Questions about calculators
How branches, fields and emails follow the answer.
Try FormDesigner for free
Create a calculator for free
Sign up and create a form in the builder, without installing software.
Don't have time to build it yourself?
FormDesigner's specialists can design, build, and configure your form, quiz, or calculator from scratch. Let us handle the complexity while you focus on your business.
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