PowerRuntime

PowerRuntime is a fully offline calculator for battery runtime. Estimate how long devices will run on batteries, power banks, UPS units, and portable power stations — with no internet, no account, and no ads.

• Power sources: Wh or Ah + V, continuous and peak power, efficiency, reserve, and idle draw
• Devices: average, peak, and cyclic loads with quantity
• Multi-device scenarios with fast recalculation
• Optimistic, expected, and conservative runtime ranges
• Continuous and peak power compatibility checks
• Compare all sources under the same load
• Saved calculation snapshots and global search
• Built-in and custom efficiency presets
• JSON export and import via the system file picker
• Light/dark theme and Dynamic Color

All data stays on your device. The app has no INTERNET permission and works completely offline.