Look at the prompt
The object name and category tell you what kind of measurement is being tested. Height is used unless the card text says otherwise.
A daily game for spatial intuition
Make the everyday measurable.
Estimate the size of familiar things, then learn the real measurement behind your guess. A small daily workout for your sense of scale.
Everyday objects
A standard door
Known measurement
200 cm
Your mental model
176 cm
03day streak
-today's score
1,284players today
Complete player guide
How to play, read the answer, and get better.
Size It Up is a daily estimating game. You see an object, make a size guess in centimeters, lock it in, then use the answer to build a stronger mental ruler.
Example round
A standard door
You move the slider to 176 cm and submit. The real measurement is 200 cm, so the game shows your accuracy, the point value, and a short note that turns the number into a reusable reference.
Start with an anchor
Use a known reference: a door is about 2 m, a counter is about 90 cm, and a basketball rim is 3.05 m.
Move the slider
Drag the handle for big changes. Use the left and right arrow keys for one-centimeter adjustments when you want precision.
Lock in the guess
Click Lock in guess or press Enter. Once submitted, the round switches from guessing to explanation.
Read the reveal
The reveal shows accuracy, points, the actual size, a comparison, a memory anchor, and the measurement basis.
Carry the anchor forward
The next time you see a similar object, use the learned number to estimate faster and with less drift.
Modes
Daily 5 and Explore work differently.
Daily 5 uses the current date to select five objects from the full library. Everyone gets the same daily set, and the set changes automatically tomorrow. Explore mode cycles through the full object bank for practice.
Daily 5Five questions, date-based rotation, final score saved on the page.
ExploreUnlimited practice, full library, useful for learning object categories.
Skip buttonThe category button advances to another object when you want a fresh prompt.
Guess176 cm
Actual200 cm
Gap24 cm
Accuracy88%
Scoring
Closer guesses earn more points.
Accuracy is based on the difference between your estimate and the real measurement. A perfect answer is 100%. A guess that is 12% away from the true value scores about 88% accuracy and 880 points.
Practical estimating tips
Use people carefully. Human height is useful, but posture and perspective can trick you.
Convert to door units. For anything taller than a person, ask how many 2 m doors could stack inside it.
Look for category clues. Furniture, appliances, sports objects, animals, and street fixtures follow different size conventions.
Trust the correction. A bad guess is valuable if you remember the anchor it creates.
Small details
What exactly am I estimating?
The game currently asks for height in centimeters. For animals, height means shoulder height. For objects like rackets, the displayed number is the object's vertical length.
Why are the drawings stylized?
The drawings are intentionally bold and readable instead of photo-realistic. The goal is to make each object recognizable at a glance while keeping the focus on scale.
Where do the measurements come from?
Each reveal names the basis: common residential dimensions, regulation standards, typical appliance sizes, or average object proportions. These are practical anchors, not forensic measurements of one exact model.
Why use centimeters?
Centimeters make small errors visible and work cleanly across tiny objects, furniture, people-scale objects, and street-scale objects.
A tiny game for better scale
Your world is full of hidden measurements.
Doors, birds, bridges, and kitchen counters are all informal rulers. Size It Up helps you notice those anchors and use them to reason about new places, objects, and distances.
Designed to leave you with more.Each round gives you a score, an explanation, and a memorable comparison. The goal is not to win a trivia round; it is to make your next visual estimate a little better.
Useful anchors1 m2 m10 m100 mStart with a door. Then stretch your mental ruler.