Balance tells you what's coming.

Know where
you stand.

Balance is a leading indicator. It declines measurably, predictably, and trackably long before it produces consequences. Most people never measure it. Stela makes it possible.

8balance tests
5 minper session
0equipment needed
Session Results
Balance Score
74
out of 100
↑ +6 this month
Baseline
87
Eyes closed
81
Feet together
78
Head turns
67
Semi tandem
55
iOS — Health & Fitness
At-home balance test · No equipment required
Peer-reviewed metric class · ICC 0.62–0.97
Your Score

Balance,
measured.

Each of the 8 tests produces a score from 0 to 100 — measuring how well you held stability in that stance. Your composite score is the single number that captures your balance system as a whole.

Two people. Both 52. Different balance scores.
Person A81
Person B43
Same age. Meaningfully different balance. Stela tells you which one you are — and gives you a number you can actually track and act on.

A number that tells you where you stand — and whether you are improving.

Your composite score is derived from all 8 tests. The result is a single number grounded in the full picture of your balance system.

Scores stabilize after 3 sessions and update with each new assessment. That makes it possible to track whether your training, your habits, or the passage of time is moving things in the right direction.


How it works

Your phone is already
a measurement device.

The accelerometer and gyroscope in a modern smartphone sample motion at 60–100 Hz. Sufficient to detect the postural micro-corrections that define balance stability. No wearables. No force plates. No appointment.

1

Position your phone

Hold your phone flat with one or both hands, arms comfortably against body. Screen faces up. No calibration required.

2

Complete the 8-test battery

Eight stances, 30 seconds each. Each isolates a different subsystem: vestibular, proprioceptive, visual, reactive, and cognitive-motor. The app guides you through every position.

3

See your score

After each stance, you get a score from 0 to 100 showing how you performed at that position. When all 8 are done, your composite score computes — a single number telling you where your balance system sits.


The 8-test battery

Every subsystem,
measured individually.

Eight stances. A score from 0 to 100 for each one. Together they tell you exactly where your balance system is strong and where it needs work.

Standing — Eyes Open

Your baseline. Feet shoulder-width apart, eyes open. Establishes how much your balance depends on vision.

Visual system

Standing — Eyes Closed

Same stance, eyes closed. Without visual input, your inner ear and body position sensing carry the full load. The gap between this score and the previous one tells you something the previous test could not.

Inner ear · Body position

Narrow Stance — Eyes Closed

Feet together, eyes closed. A narrower base makes your body's position sensing work harder — the closest you can get to a balance challenge without any equipment.

Body position

Head Turn — Reactive

Rhythmic head rotation on cue. Measures how well your inner ear and vision coordinate to keep you stable while moving.

Inner ear · Reactive

Unexpected — Eyes Closed

Feet shoulder-width apart, eyes open. At an unexpected moment, an audio cue prompts you to close your eyes. Measures reactive postural control.

Reactive balance

Forward Head Posture

Head pitched 30° forward. Measures how neck position affects your overall balance — relevant to anyone who spends time at a desk or screen.

Neck · Dynamic

Dual Task — Arithmetic

Serial subtraction while standing. Measures how cognitive effort affects your stability — a well-established signal of fall risk.

Dual-task · Cognitive

Dual Task — Verbal Fluency

Category word naming while standing. A second cognitive challenge that cross-checks the arithmetic result — two different types of thinking, same question about stability.

Dual-task · Cognitive
The science

Balance doesn't just decline.
It accelerates.

Most health measurement is retrospective — a record of what already happened. Balance is different. It declines measurably years before consequences appear, and at predictable inflection points where the rate of change shifts sharply. Most people have no measurement of where they sit at any of them.

~40

First inflection

Muscle mass and proprioceptive sensitivity begin declining. Gradual, easy to miss — and the highest-leverage window for prevention.

~60

Acceleration

Inner ear function declines and reflexes slow, compounding the losses that began at 40. Fall risk begins rising steeply.

~75

Critical zone

Steep decline. Falls become the leading cause of injury-related mortality. Intervention shifts from performance to fall prevention.

4–6×
Elevated fall risk for adults in the bottom 10th percentile of their age cohort. Most people in that group have no measurement of it. Stela tells you exactly where you stand.
Features

The full battery.
Always free.

All 8 tests and trend tracking are free. Clinical deployment, with raw sway data, and multi-patient management is available to organizations via provisioning.

Clinical
Org / provisioned

For physical therapists, coordinators, and research teams.

  • Raw sway velocity (m/s³)
  • Multi-subject profile management
  • PDF export for clinical records
  • Coordinator sleeve placement protocol
  • Group overview and aggregate trends
  • Audit log

Privacy & data

Stated
plainly.

Your account details are stored securely, never sold, and never shared for advertising. Session data syncs to encrypted cloud infrastructure for backup and cross-device access. Your anonymized sway measurements contribute to the population normative dataset that makes your score meaningful. A longitudinal dataset that does not currently exist at this scale.

Account details stay private

Your account information is stored securely. It is never sold, never shared for advertising, and never used for purposes other than operating your account.

Session data: encrypted, not sold

Sessions sync to encrypted cloud infrastructure. Your anonymized sway measurements contribute to the population normative dataset. They are never sold or licensed to third parties.


FAQ

Questions worth
answering directly.

Most at-home balance tests are subjective — stand on one leg and count to 30, with no score, no comparison, and no repeatability. Stela is different. It runs 8 standardized stances on your phone’s motion sensors and produces a 0–100 score for each one, benchmarked against your own history. The full battery takes 5 minutes and requires no equipment.
No. Stela is a measurement and tracking tool, not a diagnostic instrument. It gives you longitudinal data about your postural stability — data worth taking to a clinician. If you have a known fall history, vestibular disorder, or neurological condition, consult a clinician before using Stela unsupervised.
Each stance produces a movement measurement. Producing a 0 to 100 score for each test. Your composite score combines all 8 results into a single number. The displayed value is a rolling median of your last 3 complete sessions, which smooths out natural session-to-session variation.
The test battery runs fully offline — scoring and session storage happen on your device. An internet connection is required to sync your results and contribute to the population dataset. If you're offline, sessions queue locally and sync when connectivity is restored.
Your scores stabilize after 3 sessions. If you're monitoring the impact of a training program, monthly sessions are typically sufficient to detect meaningful shifts. Once a week gives you enough data if you are working with a clinician.
Your personal details are stored securely on your account, never sold, and never shared for advertising. Your anonymized sway measurements contribute to the population normative dataset that powers your scores.
Yes, with our clinical tier. The clinical version includes per-test raw sway velocity, PDF export, audit logging, and multi-patient management built on cloud infrastructure. Contact us to discuss clinical or research deployment.
Apple Health integration is on the roadmap. The current version stores session data in the app and syncs it to the cloud. When HealthKit integration ships it will be optional — Stela will not read from or write to Apple Health without an explicit permission grant from you.
Know your balance score

Your score is a
number worth knowing.

Five minutes. Your phone. No equipment. Free. Most people never measure this. Stela makes it possible.