Wearable Data Storage Calculator
Estimate on-device and cloud storage requirements for wearable health data based on sensor configuration, sampling rates, compression, and retention period.
About this calculator
This calculator builds a daily data budget sensor by sensor, then scales it up to a full retention period and device fleet. The accelerometer and (optional) gyroscope each contribute 6 bytes per sample across three axes, multiplied by their sampling rate and by 86,400 seconds in a day — the single largest driver of data volume at typical 25-100 Hz rates. Heart rate is handled as one of two modes: periodic mode logs a compact 4-byte BPM reading every 10 seconds (34.5 KB/day), while continuous mode captures raw 3-byte PPG samples at 25 Hz (over 6 MB/day), which produces roughly 190x more data. GPS adds 20 bytes per fix (latitude, longitude, altitude, speed, timestamp) only during the hours per day you specify active tracking; SpO2 assumes one reading per minute during an assumed 8-hour sleep window; ECG, when enabled, samples a single lead at 250 Hz for however many minutes per day you record it.
All sensor totals sum together, get a flat 5% overhead for metadata and timestamps, and are then divided by your chosen compression ratio (typical time-series compression with LZ4/zstd runs 2-4x) to estimate the realistic stored size. That daily compressed figure is projected across your retention period and multiplied by device count for a fleet total, with a rough cloud storage cost estimated at $0.023/GB/month (S3 Standard pricing at time of writing). Real-world costs will differ based on your actual cloud provider, storage tier, egress fees, and how well your specific data compresses — treat this as a capacity-planning starting point, not a final budget.
Inputs
Results
Compressed per day (MB)
8.69
Total storage per device (GB)
3.1
How to Use This Calculator
- Set the accelerometer sampling rate (Hz) and heart rate monitoring mode for your wearable.
- Select GPS fix rate and enter average daily GPS hours (workout duration).
- Enable SpO2, ECG, and gyroscope sensors that your device records.
- Enter data retention period (days), number of devices (fleet), and compression ratio.
- Review raw and compressed data per day (MB), monthly cloud storage (GB), and estimated cloud cost.
How the result changes with Compression ratio
| Compression ratio | Compressed per day (MB) | Total storage per device (GB) |
|---|---|---|
| 1.5 | 17.38 | 6.2 |
| 2.25 | 11.59 | 4.13 |
| 4.5 | 5.79 | 2.07 |
| 7.5 | 3.48 | 1.24 |
What each input means
- Accelerometer rate (Hz)
- Accelerometer sampling rate. Consumer wearables: 25-100 Hz.
- Heart rate mode
- Select the heart rate mode
- GPS fix rate (Hz)
- Select the gps fix rate (hz)
- GPS hours per day
- Average hours per day GPS is actively tracking (workouts, commute).
- SpO2 monitoring
- Select the spo2 monitoring
- ECG recording
- Select the ecg recording
- ECG minutes per day
- Minutes of ECG recording per day (single-lead at 250 Hz).
- Gyroscope
- Select the gyroscope
- Data retention (days)
- How many days of data to keep in cloud storage.
- Number of devices
- For fleet/enterprise: number of wearable devices generating data.
- Compression ratio
- Data compression factor. Typical time-series: 2-4x with LZ4/zstd.
What each result means
- Raw data per day (MB)
- Uncompressed data generated per device per day.
- Compressed per day (MB)
- Compressed data per device per day.
- Compressed per month (GB)
- Compressed data per device per month.
- Total storage per device (GB)
- Total compressed storage needed per device for the retention period.
- Total all devices (GB)
- Total storage across all devices for the retention period.
- Est. cloud cost ($/month)
- Estimated cloud storage cost at ~$0.023/GB/month (S3 standard).
- Monthly data transfer (GB)
- Data transferred from devices to cloud per month.
- Data points per day
- Total number of individual sensor readings per device per day.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersAccelerometer rate (Hz) = 50, Heart rate mode = 1, GPS fix rate (Hz) = 1, GPS hours per day = 1 = 11 input(s) provided
- Calculate Compressed per dayCompressed per day = compressedBytesPerDay / (1024 * 1024)8.69 = 8.69
- Calculate Total storage per deviceTotal storage per device = (compressedBytesPerDay * retentionDays) / (1024 * 1024 * 1024)3.097 = 3.097
- Calculate Raw data per dayRaw data per day = totalRawBytesPerDay / (1024 * 1024)26.07 = 26.07
- Calculate Compressed per monthCompressed per month = compressedMbPerDay * 30.44 / 10240.258 = 0.258
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does switching heart rate mode from periodic to continuous multiply my data volume by roughly 190x?
Periodic mode logs one compact 4-byte BPM reading every 10 seconds, producing about 34.5 KB per day. Continuous mode instead captures raw 3-byte PPG samples at 25 Hz — that's 25 samples every second instead of one every 10 seconds, and each carries more bytes — which works out to over 6 MB per day, since the calculator computes continuous-mode bytes as 3 bytes times 25 Hz times 86,400 seconds versus periodic's 4 bytes times only 8,640 readings.
At what point in the calculation does the compression ratio get applied?
The calculator first sums every enabled sensor's raw daily bytes (accelerometer, heart rate, GPS, SpO2, ECG, gyroscope, and a fixed temperature reading), adds a flat 5% overhead for metadata and timestamps, and only then divides that total raw figure by your chosen compression ratio. So compression is applied once, at the end, to the full combined sensor stream rather than separately to each sensor.
Does GPS data volume depend on the fix rate, the hours tracked per day, or both?
Both. The calculator multiplies your GPS fix rate (fixes per second) by 20 bytes per fix and by the number of seconds GPS is actively tracking, which it derives from your GPS hours per day times 3,600. Doubling either the fix rate or the daily tracking hours doubles the GPS contribution to your data budget — they're independent multipliers, not interchangeable settings.
How reliable is the $0.023/GB/month cloud cost estimate?
It's a straight multiplication of your total fleet storage (in GB) by a single flat rate modeled on S3 Standard pricing at the time this calculator was built, with no allowance for storage tiering, egress/transfer fees beyond the separate monthly transfer figure, or provider-specific discounts. Treat it as a rough planning baseline — your actual bill will depend on which cloud provider and storage class you use and how your real sensor data compresses compared to the ratio you entered.
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Fitness Tracker Accuracy Calculator
Estimate step-counting and heart-rate measurement accuracy based on sensor quality, wear fit, activity type, and skin tone.
WearablesSmartwatch Battery Life Calculator
Estimate smartwatch battery duration based on battery capacity, display settings, GPS usage, heart rate monitoring, and connectivity features.
IotIoT Data Volume Calculator
Data storage from sensor count, sample rate, and retention.
TelehealthWearable Data Volume Calculator
Data storage from wearable device count and sampling rate.
Precision AgricultureTelemetry Data Budget Calculator
Estimate cellular data usage and cost from IoT sensor count, reporting frequency, and message size.
More in Technology & Computing.