About CalGuesser
CalGuesser is a calorie guessing game with one move: it shows you two foods, hides one number, and asks whether that number is higher or lower. The gap between the two is the part you actually remember.
Below: the rules, how points work, the difference between the two modes, where the calorie numbers come from, and what the game keeps in your browser.
The rules
One round
- The reference food is shown with its calories per 100 g. The mystery food shows its photo, name and category, and hides its number behind “???”.
- Answer More or Fewer. Identical calorie counts never come up, so there is always one right answer.
- The real number counts up on reveal, along with the kcal gap to the reference food. That gap is the whole lesson.
- The revealed mystery food becomes the next round's reference, so every run is one long chain.
Points and controls
- A correct guess is worth 1 to 25 points, scaled by how close the two foods are. Close pairs pay, obvious ones barely register.
- Pairs are drawn deliberately close rather than at random, so most rounds are meant to be genuinely hard.
- Keyboard: ↑ for more and ↓ for fewer (W and S also work).
- Space skips the rest of the reveal, and plays again once a run is over. Clicking the cards does the same.
Endless and the Daily Challenge
Same rules, two different reasons to play. Endless is the arcade run you come back to; the Daily Challenge is one short puzzle that is the same for everybody that day, which is what makes a result worth sharing.
Endless
For a longer sitting, and for chasing a number.
- Three lives.
- Rounds keep coming until they are gone.
- Drawn from all 179 foods.
- High score and best streak are kept.
Daily Challenge
For two minutes a day, and for comparing.
- Ten rounds, no lives, all played out.
- The same ten foods for everyone that UTC day.
- Scored on accuracy and points.
- Emoji grid to share, and a streak to keep.
Where the numbers come from
Every food, photo and calorie count comes from Open Food Facts, a community-run database of real products, used under the ODbL and CC BY-SA licences.
The playable set is a curated subset of it: 179 foods across 11 categories, each normalised to calories per 100 g. Anything whose calorie count is unknown is left out rather than guessed at, and photos are always shown whole rather than cropped to fill, because the source images range from studio packshots to somebody's kitchen counter.
Community data is imperfect by nature: brands reformulate, regions differ, and the odd entry reflects one particular packet. Treat the numbers as good enough to argue with, not as nutrition advice.
What stays in your browser
There is no account and no server-side profile. Your record lives in your browser's local storage and nowhere else:
- Your top Endless scores, with their streaks and dates.
- Lifetime totals: games played, guesses made, correct guesses, best streak.
- Your recent Daily Challenge results, newest first.
- Whether you chose the light or the dark theme.
Two consequences worth knowing: clearing your browser data clears your record, and your history does not follow you from your phone to your laptop. See it all on the results page.
Why guessing beats memorising
Nobody reads a nutrition label and remembers it. What does stick is being wrong about something you were sure of: that granola sits where a brownie sits, that a spoon of nut butter outweighs a bar of chocolate, that drying fruit multiplies it several times over. Each of those is one round here, and the surprise is what does the teaching.
Play enough rounds and the useful thing is not a table of numbers you can recite, it is a decent instinct for which side of a menu the heavy items are on. That is the whole ambition. CalGuesser is a game about food, not a tracker, a coach or a diet plan, and it will never ask you to log a meal.