The rules, one guess at a time
Basics in 30 Seconds
Costcodle gives you one product and one hidden target price. Enter a positive plain decimal with up to two digits after the decimal point: 12.99 is valid, while $12.99 and 1,234.00 are not. You get six guesses.
Reading Feedback
Arrows show direction
An up arrow means the target is higher than your guess. A down arrow means it is lower.
Colors show closeness
| Result | Meaning | Next move |
|---|---|---|
| Green | Within 5% of the target | You solved the challenge. |
| Amber | Within 25%, but outside the win range | Make a smaller adjustment. |
| Red | More than 25% away | Make a larger correction. |
The 5% rule
The target itself is not required. A guess inside the 5% winning band is enough. For a $12.99 target, the valid winning range is $12.35 through $13.63.
A Worked Session
Suppose the target is $12.99. A guess of $20.00 is high and far, so move down. A guess of $10.00 is low and near enough to guide you upward. A guess of $15.00 is high and closer. The fourth guess, $12.50, falls inside $12.35–$13.63 and wins.
FAQ
What input format should I use?
Use only a positive decimal with zero, one, or two digits after the decimal point. Leave out symbols and separators.
What happens after six misses?
The challenge ends and the result can show the target for that published record.
Can I see earlier records?
Open the archive for saved dates, or return to Today for the current entry.