Cookie Policy

Last updated: 28 September 2026

BuildMetricLab keeps cookies to a minimum. We set no advertising cookies and run no cross-site tracking. Apart from the consent message's own record of your choice, the only non-essential cookies come from two analytics tools, described below, and our forms' spam check can set a short-lived cookie when you use a form. There is no sign-in anywhere on this site, so there is no session cookie either.

When the analytics tools run

Whether the two analytics tools load depends on where you are, and the consent message (InMobi Choice) applies the rule for your location:

• In the UK, the European Economic Area and anywhere else the consent message asks first, neither tool loads, and none of their cookies are set, until you consent.
• Elsewhere (including the United States, Canada and Australia), they load unless you turn them off. We treat a Global Privacy Control (GPC) browser signal as an opt-out, and they do not load when your browser sends it.

Wherever you are, you can change your choice at any time with the Cookie preferences link in the footer, which reopens the consent message.

Analytics — Microsoft Clarity

Microsoft Clarity shows us how the calculators are used, through aggregated heatmaps and anonymised session replays. This helps us find confusing layouts and steps that don't work well. Clarity sets two cookies:

• _clck — identifies a returning visitor so page views group into one session. Expires after about a year.
• _clsk — links page views within a single session. Expires at the end of the session.

Text you type into calculator fields is masked in your browser before anything is sent, so the values you enter are not captured. For more, see Microsoft's Privacy Statement.

Analytics — Google Analytics 4

Google Analytics 4 runs on the calculator pages and tells us which calculators are used, how visitors arrive at them, and where pages perform badly. It sets these cookies:

• _ga — distinguishes one browser from another so visits group into sessions. Expires after about two years.
• _ga_<container-id> — keeps the state of the current session. Expires after about two years.

We run Analytics for measurement only: we do not enable Google Signals, advertising features, or remarketing audiences, so your visit is not used to target ads to you, and it is not a sale or share of personal information for cross-context behavioural advertising. The numbers you type into calculators are never sent to Google. For more, see Google's Privacy Policy and how Google uses data from sites that use its services.

Consent management — InMobi Choice

Your privacy choices are collected by InMobi Choice, a certified consent management platform, and recorded in cookies on this site, each kept for up to 13 months:

• euconsent-v2 — your IAB Transparency & Consent Framework choices, where that framework applies (the UK and EEA).
• IABGPP_HDR_GppString — your choices as an IAB Global Privacy Platform string, used for US state privacy signals.
• usprivacy — your opt-out choice under US state privacy laws.

These are strictly necessary to remember your choice. See InMobi's Privacy Policy.

Price it on PlainEstimate

The Price it on PlainEstimate button under a calculator result sets no cookie and stores nothing on this site. It opens PlainEstimate, our estimate and invoice app, in a new tab, with the materials in the part of the link after the #. What PlainEstimate stores in your browser is covered by its own privacy policy. The old Estimator at buildmetriclab.com/estimator has been retired, and its address now forwards to PlainEstimate.

Strictly necessary local storage

The site uses browser localStorage (not cookies) for two small, functional purposes:

• bml-theme — your chosen theme (light or dark). If the key is absent, your operating-system preference is used.
• bml-project — your My Project take-off. When you press Save to My Project on a calculator, the tool, the inputs and the result you chose to save are kept here so you can review or print them together on the My Project page. It holds only what you explicitly save — no account, no identifiers, no tracking — and never leaves your device. Remove individual items or clear the whole list at any time from that page.

These stay on your device and are never sent to us. The US units / Metric switch on the calculators stores nothing: it follows your browser's language setting, or a units value in the page address, for that page view only. Calculator inputs are not stored automatically — refreshing the page resets them. Only what you deliberately save to My Project persists.

Anonymous usage logging (no cookies)

Separately, we record an anonymous, cookieless event when a calculator is used: which tool it was, the name of the figure it produced, your approximate country/region and device type (from network request headers). The values you type and the results calculated from them are not transmitted or stored. It sets no cookie, stores nothing on your device, and contains no information that identifies you. Because it does not store or access information on your device, it does not require consent.

No other tracking

Apart from the two analytics tools described above, there are no tracking or advertising tags on this site — no Facebook Pixel, no ad network pixels, no cross-site profiling. If we add anything further that stores information on your device, we will update this page, and ask for consent first wherever the law requires it.

Clearing data

You can clear the bml-theme and bml-project localStorage entries, and any Microsoft Clarity or Google Analytics cookies, at any time via your browser's site-data settings (or use Clear all on the My Project page).