A one-sentence description is a plain sentence that says who a business is for, what changes for them, and one concrete detail about how. It has to work on its own, for a stranger, in a bio, a listing or an introduction.
- One sentence, three parts: buyer, outcome, one concrete detail.
- Describe the change for the buyer, not the mechanism.
- Clear but generic fails the swap test. Specific but unclear fails the stranger test. You need both.
- Once it passes, use the same sentence on every surface a stranger sees first.
Why one sentence is so hard
Founders usually know too much. Every feature feels important, every audience feels worth keeping, and the technology is the part they are proudest of. So the sentence grows into a list, or it retreats into a category word that offends no one.
Those two failures map onto two different readings of market fit. A sentence that tries to say everything usually has a coverage problem: the right buyer cannot find themselves in it. A sentence that says "we are a platform for modern teams" has a distinctiveness problem: every rival could publish it. The goal is a line that is both easy to understand and hard to copy.
The formula
Start here, then make it sound like you:
Each part has one job.
- The buyer lets the right person recognise themselves. Name the one you serve best, not everyone you could serve. "Independent physical therapy clinics" beats "healthcare providers".
- The outcome or problem is the before and after, in the buyer's words. If you sell software that reconciles data, the buyer's words might be "stop fixing spreadsheets every Friday".
- The concrete detail is what makes it yours: a format, a turnaround, a constraint you keep, or a method. It is the part that passes the swap test.
Leave out how the technology works, product names your buyer has never heard, and adjectives like innovative, seamless or powerful. They cost words and prove nothing.
Three stranger tests
Your team cannot judge the sentence, because they already know what it means. Strangers can. Say it out loud, once, to someone outside your industry, and watch for three things.
| Test | What to ask | It passes when |
|---|---|---|
| Repeat-back | "Can you tell me what we do, in your own words?" | They say it without your jargon and without leaving out the buyer. |
| Who is it for | "Who do you think would buy this?" | They name your real buyer, or someone close to them. |
| First question | Say nothing and wait. | Their first question is about the offer, such as price, how long or how it works, not "what does that mean?" |
Then run the swap test once: put a direct competitor's name in the sentence. If it is still true for them, the concrete detail is not concrete enough yet.
The 10-minute exercise
- Write the long version. Two minutes explaining the business to a friend, in as many sentences as you need. Do not edit.
- Circle three things. Who it is for, the outcome or problem, and one concrete detail about how. Cross out technology, process names and adjectives.
- Fill the formula. Under about 25 words, in the buyer's words.
- Run the swap test. If a rival could say it, change the buyer or the detail.
- Test it on three strangers. Note the words they use when they repeat it back and the first question they ask. Rewrite once, using their words where they are clearer than yours.
Hard-to-explain businesses
Technical, deep-tech and infrastructure founders often say their product cannot fit in one sentence. It usually can, once the sentence describes the change rather than the machine. Two moves help:
- Describe what the buyer stops doing. People understand the work they would like to stop far faster than a new capability.
- Name a familiar comparison only if it is honest. "Like X, but for Y" can be a fast handle in conversation. On your site it works best as the second sentence, after the plain one, so you are not defined by someone else's brand.
An illustration (made-up business, not a client)
A small studio that builds data pipelines starts with: "We build scalable, AI-ready data infrastructure for modern businesses." Strangers nod and ask what that means. A rival could publish it word for word. After the exercise: "We help regional retailers stop rebuilding the same sales spreadsheet every Monday, by connecting their tills and online store into one weekly report." The strangers repeat it back as "you fix shops' Monday spreadsheet problem," and their first question is how much it costs. That is a sentence doing its job.
Once it works, put it everywhere
A good sentence on one page is not enough. Coverage means a stranger meets the same idea wherever they first find you: the homepage headline or the line under it, every social bio, directory and marketplace listings, the pricing page, your email signature and how you introduce yourself. If old pages still say the previous version, the messaging consistency audit will find them. If you want to turn the sentence into a dated commitment you can score yourself against, the brand promise template is the next step. Personal brands can use the same approach with the positioning line guide.
Then give it time and watch what comes back. When customers start describing you in words close to your sentence without being prompted, that is resonance, and it is the signal that the sentence is working beyond your own pages.
Sightbox Studios. "How to say what you do in one sentence." Market Fit Read, 3 November 2026. https://promisemarketfit.com/say-what-you-do-in-one-sentence
Link to it: <a href="https://promisemarketfit.com/say-what-you-do-in-one-sentence">How to say what you do in one sentence</a>
Keep reading
- Free market fit self-score
- The swap test for your homepage headline
- How to write a brand promise statement
- Why your website isn't converting
- Your personal brand positioning line
- Messaging consistency after a rebrand
- Message-market fit vs promise-market fit
- Sample Market Fit Read (fictional company)
Questions
How do I explain what my business does in one sentence?
Name who it is for, the problem or outcome they care about, and one concrete detail about how you deliver it. Say it in words the buyer already uses. Then test it on a stranger: if they can repeat it back and ask a sensible follow-up question, it works.
What is the difference between a one-sentence description and a tagline?
A tagline can be clever, short and a little vague because it sits next to other context. A one-sentence description has to work alone, in a bio, a directory listing or an intro, for someone who has never heard of you. Write the plain sentence first. A tagline can come later.
How do I describe a technical or complicated product simply?
Describe the before and after for the buyer, not the mechanism. Leave out how the technology works and say what changes for the person using it. Keep one concrete detail, such as a format, a turnaround or a named audience, so it does not turn generic.
How do I know if my one-liner is working?
Run it past people who do not know your business. If they can say it back in their own words, guess the right buyer, and ask a question about the offer rather than about what you mean, it is working. If they repeat your jargon or ask what it means, it is not.
Should my one sentence mention my competitors or category?
Name the category only if buyers already search for it, because it helps them file you. Then add the detail that makes you different. A sentence that is only a category, like a design agency for startups, fails the swap test because every rival could say it.
Where should I use my one-sentence description?
Everywhere a stranger meets you first: the homepage headline or the line under it, every social bio, directory and marketplace listings, your email signature and how you introduce yourself. Using the same sentence on every surface is what makes it stick.
Is a one-sentence description the same as a brand promise?
They are close relatives. The description says what you do. A brand promise says what you commit to delivering, for whom and how, and it is dated so it can be scored. A good one-liner is often the promise said in plain words.