About this game

Box Balance is a game about one equation: torque equals force times lever arm. A light crate placed far from the pivot turns the plank exactly as much as a heavy crate placed close in, and the game shows you that distance on screen before you commit.

The plank itself is driven by the torque balance rather than by the physics solver, which keeps the pivot exact. The crates on top are ordinary rigid bodies with real friction, so a steep plank lets them slide before it lets them fall — and a sliding crate changes the balance again while it moves.

How to play

  1. Move the pending crate left and right along the drop line at the top of the screen.
  2. Press Space to drop it. Watch the tilt meter as it lands.
  3. Wait for the plank to settle. The next crate appears automatically.
  4. Keep the tilt inside the safe band. Tip past about 23 degrees and the load is lost.
  5. If a crate slides off and hits the floor, the run ends.

Physics mechanics

Here is what the simulation is actually doing while you play.

Torque and lever arm

Each crate contributes mass × gravity × its horizontal distance from the pivot. Doubling the distance doubles the turning effect, which is why the distance readout matters more than the crate size.

Moment of inertia

The plank's resistance to turning grows as the load spreads outwards, using the parallel axis theorem — each crate adds mass × distance². A wide load is genuinely slower to swing than a compact one of the same total weight.

Friction on a slope

Crates grip the plank until the tilt exceeds what friction can hold, then they slide. Because sliding moves their lever arm, a slide usually makes the tilt worse before it makes it better.

Objective

Balance as many crates as possible. The run ends when the plank tips past its limit or a crate reaches the floor.

Scoring

  • Each settled crate scores 60 points plus up to 140 more the flatter the plank is when it settles.
  • Settling with the plank near level starts a balance streak worth 25 points per crate.
  • A slide that changes the tilt breaks the streak.

Scores, favourites and play history are stored in your own browser using localStorage. There is no account, no leaderboard and no server: clearing your browser data clears them, and they do not follow you to another device.

Tips

  1. Alternate sides. The simplest reliable strategy is strictly alternating left and right of the pivot, roughly matching distances.
  2. Read the distance label. The pending crate shows how far from the pivot it will land. Match it against the last crate you placed on the opposite side.
  3. Dense crates go close in. The tall pink crates are the heaviest. Placing one far out is almost always fatal.
  4. Wide crates are stabilisers. The flat purple crates have a broad base and low profile — they are the best thing to land on top of an uneven stack.
  5. Let it settle fully. Dropping while the plank is still moving compounds the error. The next crate does not appear until the plank has settled, so use that pause.

Difficulty

Medium. The first five or six crates are forgiving because the plank has little load and plenty of damping. Past ten crates the moment of inertia is high enough that recovering from a bad placement takes two or three careful drops.

Features

  • Live torque balance computed from every crate on the plank
  • Four crate types with genuinely different mass and shape
  • Visible tilt meter with safe, warning and critical bands
  • Balance streak bonus for settling the plank near level
  • Distance-from-pivot readout on the pending crate

How accurate is this?

Physics Arcade games use simplified, tuned physics built for playability. They are not scientific simulations: forces, masses and timings are chosen because they feel good at 60 frames per second, not because they match measured values. Where a game departs from real-world behaviour in a way that matters, the game page says so.

Box Balance – FAQ

Why did a light crate tip the plank?

Because it landed far from the pivot. Turning effect is mass times distance, so a light crate at double the distance matters as much as a heavy one close in.

Can I move crates after dropping them?

No. Once a crate lands it is part of the load. The only control you have is where the next one goes.

Why do crates sometimes slide?

Friction can only hold a crate up to a certain slope angle. Past that, it slides — and because sliding moves it further out, the tilt usually gets worse first.

What is the balance streak?

Settling the plank close to level keeps a streak going, and each streak crate adds 25 points to the score. Any settle at a steep angle resets it.