Put these calculators on your own website

If you advise business owners, these are yours to use. One line of HTML puts a working calculator on your page — free, including commercially, with no sign-up and no account. The figures your visitors type never leave their browser, so there is nothing for us to hold.

How to add one, in three steps

Pick a calculator below and press Copy the code.
In your site editor, add a block that accepts raw HTML — a Custom HTML block in WordPress, a Code block in Squarespace, an Embed HTML element in Wix, or anywhere in the page source on a hand-built site.
Paste the line in and publish. Nothing to install, no plugin, no key.

The code is an iframe with a fixed height, chosen to fit the tallest result each calculator produces. If your column is narrower than about 380px, raise the height number until nothing is cut off — it is the only value you should need to change.

Business valuation calculator

Normalised profit and an indicative value range from the owner’s own figures, with every step of the arithmetic shown.

Who it suits: Accountants, bookkeepers and advisers whose clients ask what the business is worth — and who would rather hand them a tool than an estimate they have to stand behind.

What leaves the browser: The figures stay in the browser. When your visitor calculates, the widget posts one anonymous event to us — a random per-tab id, the address of the page it is embedded on, and nothing else. This one also reports whether the result came out positive or negative — one word, never a number.

See the widget on its own →

Paste this where you want it to appear:

<iframe src="https://www.instilus.com/embed/business-valuation-calculator" width="100%" height="1400" style="border:0" loading="lazy" title="Business valuation calculator"></iframe>

Acquisition affordability calculator

Whether a business can pay for its own purchase in year one, and what happens to that answer at 10% below plan.

Who it suits: Anyone advising buyers. Nothing else like it exists as a free widget, and it answers the question a buyer has before the asking price is even worth discussing.

What leaves the browser: The figures stay in the browser. When your visitor calculates, the widget posts one anonymous event to us — a random per-tab id, the address of the page it is embedded on, and nothing else.

See the widget on its own →

Paste this where you want it to appear:

<iframe src="https://www.instilus.com/embed/acquisition-calculator" width="100%" height="1500" style="border:0" loading="lazy" title="Acquisition affordability calculator"></iframe>

EBITDA and adjusted EBITDA calculator

EBITDA, then adjusted EBITDA after owner add-backs and one-off costs — the figure a buyer actually works from, rather than the one most free tools stop at.

Who it suits: Accountants and corporate finance advisers. The add-back conversation is the one clients get wrong most often, and a tool settles it faster than an explanation.

What leaves the browser: The figures stay in the browser. When your visitor calculates, the widget posts one anonymous event to us — a random per-tab id, the address of the page it is embedded on, and nothing else.

See the widget on its own →

Paste this where you want it to appear:

<iframe src="https://www.instilus.com/embed/ebitda-calculator" width="100%" height="1400" style="border:0" loading="lazy" title="EBITDA and adjusted EBITDA calculator"></iframe>

Break-even calculator

The sales a month needed to cover costs, and the sales needed to reach a target profit. Two different numbers, and most owners only ever work out the first.

Who it suits: Business advisers, lenders and start-up support sites. It suits any audience earlier in the journey than a valuation.

What leaves the browser: The figures stay in the browser. When your visitor calculates, the widget posts one anonymous event to us — a random per-tab id, the address of the page it is embedded on, and nothing else.

See the widget on its own →

Paste this where you want it to appear:

<iframe src="https://www.instilus.com/embed/break-even-calculator" width="100%" height="1300" style="border:0" loading="lazy" title="Break-even calculator"></iframe>

Profit margin and markup calculator

Gross profit, margin, markup and the price a target margin requires — all at once, so nobody has to convert one into the other by hand.

Who it suits: Retail, wholesale and e-commerce sites. Confusing margin with markup is the most common costly arithmetic error in pricing.

What leaves the browser: The figures stay in the browser. When your visitor calculates, the widget posts one anonymous event to us — a random per-tab id, the address of the page it is embedded on, and nothing else.

See the widget on its own →

Paste this where you want it to appear:

<iframe src="https://www.instilus.com/embed/profit-margin-calculator" width="100%" height="1200" style="border:0" loading="lazy" title="Profit margin and markup calculator"></iframe>

Freelance rate calculator

Works back from the income you want to the hourly and day rate that gets you there, including the utilisation most rate calculators quietly ignore.

Who it suits: Freelance communities, job boards and agency resource sites, where "what should I charge" is asked constantly and answered badly.

What leaves the browser: The figures stay in the browser. When your visitor calculates, the widget posts one anonymous event to us — a random per-tab id, the address of the page it is embedded on, and nothing else.

See the widget on its own →

Paste this where you want it to appear:

<iframe src="https://www.instilus.com/embed/freelance-rate-calculator" width="100%" height="1400" style="border:0" loading="lazy" title="Freelance rate calculator"></iframe>

The terms, in full

Free, including for commercial use. On client sites too. There is no paid tier.
No sign-up, no key, no account. Paste the code and it works.
The numbers your visitors type never leave their browser. Not to us, not to anyone. There is no email field and no account.
Nothing is written to your visitor’s device. No cookie, no local storage, nothing to consent to and nothing for you to add to a banner.
Each widget does send us one anonymous event when someone calculates. It carries a random per-tab identifier held only in memory, the address of the page the widget is embedded on, and the event name — so we can see the widget is being used and on which sites it earns its place. No figures, no name, no email, no advertising, no profile. The business valuation calculator also reports whether the result came out positive or negative; each widget below says what it sends before you paste it.
Keep the attribution line. One line at the bottom saying the calculator is by Instilus, linking back. That is the whole arrangement and the only thing we ask.
Do not present it as your own valuation. It is arithmetic shown in full, not an appraisal, and the widget says so.

Arithmetic and general information only — not financial, tax, legal or investment advice, either for you or for the people who use it on your site.

Why we give these away

Because it is a better trade than it looks. You get a genuinely useful page instead of another contact form, and your reader gets an answer without having to ask anyone for it. We get a link, and the small number of people who want the full workbook afterwards find their way to it.

If you would rather see what we sell before putting us on your site, that is fair: the toolkit sample shows every sheet and every formula, with no email.