Template Overview

This BMI calculator template asks for two numbers, height and weight, then returns the calculated body mass index on a result page. The calculation runs on involve.me's Formula Builder, so the maths is a live formula you can read and edit rather than fixed code. Set the input unit labels to metric or imperial, adjust the decimal precision, and change the wording on the result page to match how your business talks to clients.

A calculator on its own is a nice page. A calculator attached to a follow-up is a lead source. Add a name and email step before the result and the visitor arrives in your contact list already segmented by the number they just produced. Because the BMI figure is stored as a formula variable, you can branch the follow-up on it: someone in one band gets a different email sequence, a different offer, and a different call to action than someone in another. That routing runs on involve.me's built-in email automation, so nothing needs to be stitched to an outside platform to make the follow-up work.

Use it for gyms and fitness studios, wellness and nutrition coaches, med spas, weight management programs, and health insurance brokers. Embed it inline on a services page, trigger it as a pop-up from a call to action, or publish it as a standalone link for social and email. Add a not-medical-advice disclaimer and a consent checkbox to keep the flow appropriate for health-adjacent data, and pass UTM parameters in through hidden fields so you can see which channel produced which lead.

Key Features

Two-input calculator collecting height and weight as number-only fields with unit labels shown as a suffix, so the input is unambiguous.
Formula Builder calculation that computes BMI from the two inputs and displays it to a set number of decimals, editable without code.
Result page with reference bands showing the standard WHO and CDC categories next to the visitor's own figure so the number means something.
Social sharing on the result letting visitors post their outcome, which brings referral traffic back to the calculator.
Lead capture with OTP verification so the email attached to a result is a real address and not a throwaway.

Benefits

A reason for cold traffic to give you an email. People who will not fill in a contact form will enter two numbers to get a result, which makes a calculator one of the cheapest ways to open a conversation.
Leads arrive pre-segmented. The BMI figure is captured as a variable on the contact record, so your follow-up can speak to the specific situation instead of sending everyone the same welcome email.
The follow-up runs itself. Built-in email automation sends the sequence based on the result, the answers, and later opens and clicks, without an external email platform in the chain.
It goes live on any site. Embed inline or as a pop-up with a div wrapper and script tag, or publish it as a standalone page, with no developer needed for either route.
Junk submissions stay out. CAPTCHA, OTP verification, and disposable email blocking mean the contact list you build from the calculator is worth emailing.

How it works

Customize
Set the unit labels on the height and weight fields to match your market, replace the default suffix with your preferred unit, and rewrite the result page copy in your own voice. Adjust the decimal setting on the calculation if you want a rounder number.
Configure
Add a contact step before the result page to capture name and email, switch on OTP verification and CAPTCHA, and add a consent checkbox plus a short not-medical-advice notice. Use hidden fields to pass UTM parameters into every submission.
Connect
In the Connect tab, send contacts and their BMI value to your CRM, email platform, or booking tool through involve.me's 50+ native integrations, Zapier, or webhooks. Then build the email sequence inside involve.me and branch it on the result.
Share
Embed the calculator inline on a services or pricing page, set it as a pop-up on a high-traffic page, or share the standalone URL in social posts and newsletters.
Analyze
See how many visitors start versus finish, where they drop off, which channel sent them, and how the resulting contacts move through the email sequence.

Frequently Asked Questions

: A BMI calculator template is a prebuilt interactive flow that collects height and weight, calculates body mass index, and shows the result to the person who entered the numbers. Unlike a static chart, it is a working calculator you can publish on your own site, brand as your own, and connect to your contact list.
: In metric units, BMI equals weight in kilograms divided by height in metres squared. In imperial units, BMI equals 703 multiplied by weight in pounds, divided by height in inches squared. The standard reference bands used by the WHO and CDC are under 18.5, 18.5 to 24.9, 25 to 29.9, and 30 or above.
: Put weight in one cell and height in another, then in a third cell enter a formula dividing weight by height squared, for example =B2/(B3^2) for metric values. That gives you a working spreadsheet, but it stays a spreadsheet: you cannot embed it on a page as an interactive element, it does not capture who used it, and it cannot trigger a follow-up email. This template does the same calculation in a form you can publish and connect to your contact list.
: Start from this template, set your unit labels, add a contact step if you want the lead, then embed it. The embed is a div wrapper plus a script tag that you paste into your page, which works on WordPress, Shopify, Webflow, Squarespace, and any site where you can add HTML. You can also describe what you need to the AI Agent and have it generate the funnel and the follow-up sequence from a prompt.
: Yes. Embed it inline so it renders inside your page layout, or as a pop-up triggered by a button. Both use a div wrapper and script tag. The standalone landing page URL stays available at the same time, which is useful for social posts and email links.
: Yes. The unit shown next to each input is a label you set, so you can publish a metric version and an imperial version, or add a question asking which system the visitor uses and apply Logic Jumps to send them to the matching input page. The Formula Builder handles either calculation.
: Yes, and this is the single change that turns the calculator into a lead source. Add a contact step ahead of the result page so the visitor enters name and email to see their number. Enable OTP verification on that field to confirm the address is real before it enters your workflow.
: Yes. Build the flow as a Score-based Outcomes funnel and map each band to its own outcome page, so the wording, the offer, and the next step differ by result. You can also enable Personalized AI Text on an outcome page to generate a unique explanation for each respondent rather than showing everyone the same paragraph.
: Yes. involve.me's built-in email automation sends sequences that branch on the calculated value, the answers given, and later opens and clicks. A visitor in one band can receive a different sequence from a visitor in another, all inside the same subscription as the calculator.
: Put one on it. BMI is a screening estimate, not a diagnosis, and it does not distinguish muscle from fat or account for age, sex, ethnicity, or body composition. Add a short notice on the result page stating that the figure is informational and not medical advice, and pointing people to a qualified professional for interpretation. Place it next to the result where it will actually be read.
: involve.me is SOC 2 Type II audited and GDPR-compliant. Add a consent checkbox before the contact step so the visitor agrees to how their data is used, and keep that consent separate from any marketing opt-in. Funnels can also be password protected if the calculator is for an internal or client-only audience.
: Ones where a single new client is worth a meaningful amount: gyms and studios selling memberships or personal training, nutrition and wellness coaches selling programs, med spas, weight management clinics, and health insurance brokers. The calculator is a low-friction first step in front of a high-value offer, which is where the follow-up sequence earns its keep.
: Yes. Use hidden fields to carry UTM parameters or a user identifier through the funnel URL, so every contact record arrives with attribution attached and you can tell which channel produced which lead.
: The free plan covers it, with 3 live funnels included. Paid plans start at $29 per month billed annually and add funnel capacity, branding removal, custom domains, and more integrations. The AI Agent is available on every plan including free.