Soreno
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Market sizing builder, top‑down and bottom‑up

Pick one of seven markets or your own, change any assumption and watch both routes update line by line. You see how far apart they land, what the gap means, and get a link to send your build to a friend.

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Runs in your browser. The share link holds your build, nothing about you.

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Size it two ways, then compare

Every line is an input. Change one and both totals, the gap and the read update at once.

Step 1. Pick a market

Seven markets from our worked interview questions, or one of your own. Each starts from the worked answer's numbers, and any line we added ourselves is tagged as our assumption.

Market

Estimate the annual market for electric scooters in the United States.

Lines without a tag come from our worked answer. Lines tagged as our assumption are round numbers we picked for this builder. Change any of them. Read the worked answer

Step 2. Build it both ways

Change any number. Each line shows where the chain stands after it.

Top-down

Start from households where a scooter is practical and narrow to owners.

  1. About 30% of 130 million US households

  2. = 2 million owners
  3. = 500,000 scooters bought a year

  4. 200,000 shared scooters that last about two years

    = 600,000 scooters sold a year
  5. = $300 million a year
Top-down total
About $300 million a year

Bottom-up

Start from the stores that sell scooters and scale up.

  1. Our assumption, change it

    Big-box, electronics and bike shops

  2. Our assumption, change it

    = 300,000 scooters sold in stores

  3. Our assumption, change it

    The rest are bought online

    = 600,000 consumer scooters a year
  4. = 700,000 scooters sold a year
  5. = $350 million a year
Bottom-up total
About $350 million a year
Step 3. Compare the routes
Top-down
$300 million
Bottom-up
$350 million

Gap: 17%

The routes are 17% apart: close enough for a range.

Give both ends as your range, then name the input you trust least.

Sanity check

2 million owners is under 1% of the roughly 260 million US adults. Does that fit what you see in a big city, and in the suburbs?

Say your estimate out loud to an AI interviewer

Building it on a page is half the skill. Soreno's AI interviewer gives you a sizing question, asks why you picked each number and scores how you got there. The 7-day free trial includes 6 practice credits (a full case uses up to 3) and 3 drills.

Practice with the AI interviewer

Account required to start the trial. Cancel anytime before it ends.

How to read it

Two routes, one answer

Top-down starts from a big number you can defend, like 130 million US households, and cuts it down with shares. Bottom-up starts from one thing you can picture, a store, a dentist, a theater seat, and multiplies out. In an interview you lead with one and use the other to check it.

When the two land within about 15% of each other, you are done. Give one round number and say which route you trust more. Up to about 1.5 times apart, give both ends as a range. Further apart than that, don't average them. Put the chains side by side and find the line that does the most work. It is usually a share or a rate you guessed in a hurry.

Then say the answer the way you would to a partner: the number, the one assumption that moves it most, and what you would check first with more time. That last part is what interviewers remember.

Keep going

Learn the method, then practice live

Read the guides, try a timed prompt or practice out loud with an interviewer.

FAQ's

Frequently Asked Questions

Everything you need to know about Soreno, answered in one place.

Top-down starts from a large total, such as people or households, and narrows it with shares until you reach the buyers and what they spend. Bottom-up starts from one unit, such as a store, a worker or a seat, works out what it sells and multiplies by how many there are. Each catches mistakes the other misses, which is why it pays to do both.
Within about 15%, give one number. Up to 1.5 times apart, give a range. From 1.5 to 3 times apart, find the input that differs most. Three times or more usually means a missing piece, such as online sales or rental fleets, or a day mixed up with a year. Find it before you answer.
No. They are round numbers you could say out loud in an interview, not sourced statistics. Lines without a tag come from the worked answer on our question page for that market. Lines tagged as our assumption are round numbers we picked for the builder, mostly on the bottom-up side, such as how many stores sell scooters. Change any of them. The point is the structure and the check, not the exact figure.
Yes. Use the button under the comparison to copy a link. It holds the market and the numbers you typed. For your own market it also holds the name you gave it and the names of your lines. Nothing about you goes in it, and whoever opens it sees the same build.
Yes, with no sign-up. It runs in your browser. To practice saying an estimate out loud, Soreno's AI interviewer asks follow-ups on your assumptions and scores your answer. The 7-day free trial includes 6 practice credits (a full case uses up to 3) and 3 drills.

Ready for an interviewer that talks back?

Start the 7-day free trial and run your first full case with the AI interviewer today.

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