Costcodle strategy: from one guess to a smaller range

A reply in Costcodle is a statement about the hidden price, not about your guess. Once you read it that way, every guess produces a usable interval, duplicate thinking disappears, and you can see exactly when six attempts are enough and when they are not. Every number below comes from the game's own comparison rule and its 152-item catalog.

The two thresholds

With g as your guess and t as the stored target price, the game computes d = |g − t| ÷ t. A guess wins when d ≤ 0.05 and turns yellow when d ≤ 0.25. Both are shares of t, so the same dollar miss can be warm on an expensive item and cold on a cheap one.

What each reply proves

Rearranging the rule gives a bound for every reply. This table uses a guess of $22.00 as the worked value:

A red reply is not “25% away”; it is “more than 25% away”, with no upper limit. That is why red gives one bound only, while yellow gives two.

The dollar endpoints are rounded for reading. The exact bounds are 22/1.05 ≈ $20.9524 and 22/0.95 ≈ $23.1579, so a $20.95 target is just outside the win band (5.01% away) while $20.96 is inside (4.96%). The warm-down row ends at $20.95, and the warm-up row starts at $23.16. Use the fraction when a single cent decides the reply.

The same guess can be yellow or red

Guess $22.00 against the catalog's Coca-Cola de Mexican Glass Bottles, 24 x 16.9 oz at $26.99 and the difference is $4.99, which is 18.49% of the target: yellow, with an up arrow. Move the target to $30.00 and the same $22.00 guess is $8.00 away, 26.67% of the target: red, still pointing up. The guess did not change; the denominator did.

The practical consequence: never convert a reply into a distance from your own guess. A red down arrow at $40.00 proves the target is under $32.00 (0.8 × 40), not under $30.00. Skipping that step throws away two dollars of the range you just paid a guess for.

Four guesses on a real catalog item

The item is Coca-Cola de Mexican Glass Bottles, Made with Pure Cane Sugar, 24 x 16.9 oz, stored at $26.99. The replies below are what the game's comparison produces for those guesses. This is a computed demonstration from the catalog value, not a recorded player session.

Two things in that table are worth copying. First, each new reply is intersected with everything proven so far: $22 narrows the range from $13.33–$32.00 to $23.16–$29.33, raising the lower bound as well as lowering the top. Second, $26.00 was a winning guess for this stored target, not a guaranteed move from the range. Its winning target interval is 26/1.05 ≈ $24.76 to 26/0.95 ≈ $27.37, and $26.99 sits inside it. The range still allows targets outside that interval: $29.30 is |26 − 29.30| ÷ 29.30 = 11.26% away and returns yellow. To guarantee a win, the entire known range would have to sit inside one guess's winning interval: 0.95g ≤ $23.1579 and 1.05g ≥ $29.3333 require g ≤ $24.37 and g ≥ $27.94 at the same time, which is impossible. At that point the next guess buys information; it does not guarantee a win.

Six guesses are not a promise

Treating the game as a clean binary search is reasonable, and it is still not enough on its own. The catalog runs from $2.99 to $1,799.99, a span of $1,797. Perfect halving leaves about $899, $449, $225, $112 and $56.16 after one to five guesses. For a guess of g, the winning targets form the interval from g/1.05 to g/0.95, whose width is about 0.10025 × g — not a fixed share of the target. A $27.00 guess therefore covers about $2.71 of target prices. Covering the remaining $56.16 interval needs 0.10025 × g ≥ $56.16, so g would have to be about $560 or more. A halving path from $899 cannot reach that in six guesses.

The conclusion is not “give up”; it is that the first guess should not come from the middle of the catalog range. It should come from the package: 5 lbs of frozen nuggets, a 12-count bakery box and a seven-piece patio set do not live in the same price universe. A category-based first guess usually beats $900 by a wide margin, and then halving works on a much smaller interval.

Packaging and unit price

Most disagreements about a guess are really disagreements about quantity. These units are computed from catalog names and stored prices:

The clearest lesson is the pair of water cases. Both cost $5.99, but one holds 568.8 fl oz and the other about 507.2 fl oz, so the per-ounce cost differs by roughly 12%. Counting packages without reading sizes gives you the wrong anchor. The same trap appears with cans: 24 x 12 oz is 288 fl oz, while 24 x 16.9 oz is 405.6 fl oz — about 41% more liquid for the same count.

Three exercises

Use only the table above. Write the answer down before opening it.

Common mistakes

• Treating 5% as ±5% of the guess. A $50.00 guess does not win from $45.00 to $55.00; it wins for targets from $47.62 to $52.63. A $50.00 target guessed at $45.00 is a 10% miss and returns yellow.
• Reading yellow as “very close”. Yellow spans a wide band — for a $50 target, every guess from $37.50 to $47.49 and from $52.51 to $62.50 is yellow.
• Ignoring the count. 72 mini bagel bites and 12 croissants are both “a box”, at $8.49 and $4.99.
• Trusting the photo alone. A multipack photo may show one unit, and packaging changes.
• Assuming the stored value is today's shelf price. Reference values have no verified collection date and are not shopping advice.
• Assuming six guesses always suffice. See the halving calculation above.

Where this method stops

The catalog is finite at 152 items and each stores one fixed value; there is no live pricing feed, no location adjustment and no verified collection date. None of the examples on this page are taken from another player's game or from another site's daily answer. They are calculations from the same formula the game runs, so you can reproduce every number by entering the same guesses after a round ends.

Related games with different feedback

• Phoodle — guess a five-letter food word in six tries, with per-letter colour feedback. Costcodle gives one numeric distance to a stored price and no letters; Phoodle gives positional letter information and no numbers.
• Colordle — guess a colour and see a match percentage for the RGB values. Both games reduce a guess to one number, but Colordle's percentage compares a guessed colour with a hidden colour, while Costcodle's compares a dollar amount with a hidden price.

Play Costcodle Rules and controls