Use a hard, level surface
Measure on a hard floor against a straight wall rather than on thick carpet. Ask the rider to stand naturally with feet flat and together, shoulders relaxed, and eyes looking straight ahead. Place a rigid, flat object against the wall at the top of the head and mark or measure that point.
Measure more than once
If a child is close to an attraction minimum, take the measurement a few times. Small differences in posture, the floor, the measuring tool, hair, or rounding can matter when you are planning around a threshold. Recording the conservative measurement is usually the better planning assumption.
Important: Do not plan a trip around the expectation that a borderline home measurement will be accepted. Parks may use different measuring devices and procedures, and staff decisions at the attraction are final.
Use the measurement for expectations, not promises
The value of measuring before a trip is that it helps a family talk about likely options. It can identify rides that are probably available to everyone, attractions that may require a split plan, and situations where a child may need a backup activity if the on-site measurement is different.
Recheck before travel
Children grow quickly, and attraction policies can change. Recheck the rider shortly before the trip and verify any especially important attraction directly with the operator. Ride Heights is designed to organize that planning process, not replace on-site safety decisions.