Formula
Days available = Data allowance GB × 1,000 ÷ Average daily use MBDirect answer
Convert the data allowance to megabytes and divide by the average daily use. Google’s Android Help documents device-level mobile-data usage controls; use the usage figure from your own device or carrier for the daily input rather than relying on a generic activity estimate.
Variables and formula
- Data allowance: plan allowance in decimal GB.
- Average daily use: your chosen average in MB per day.
Days available = Data allowance GB × 1,000 / Average daily use MB
Reproducible example
With a 20 GB allowance and 800 MB per day, 20 × 1,000 = 20,000 MB. Dividing by 800 gives 25 days. The same daily use is 800 × 7 / 1,000 = 5.6 GB per week.
Interpretation
The answer is a planning estimate at the entered average. If usage rises for streaming, downloads or tethering, the allowance can end sooner; lower usage can make it last longer.
Assumptions and limitations
- This calculator uses the decimal plan units 1 GB = 1,000 MB.
- The daily average is steady.
- Carrier accounting, rollover, throttling and background use are not modelled.
Common mistakes
- Entering a monthly total as a daily average.
- Assuming a device counter and carrier counter always use identical rules.
- Forgetting data use outside the phone, such as tethered devices.
Assumptions
- The decimal plan units use 1 GB = 1,000 MB.
- Background use, rollover rules, throttling and carrier-specific accounting are excluded.
Sources and methodology
CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.
- Manage your mobile data usage; Google Android Help; accessed Jul 30, 2026