Enter values
Formula and methodology
Wh mode uses entered watt-hours. Ah mode first estimates Wh = Ah × nominal V. Runtime ≈ Wh × efficiency × usable fraction / load watts.
How to use the result
Check that each input uses the intended unit, then compare the displayed result with the assumptions above. Recalculate when the source values or operating conditions change. Do not use an estimate as a substitute for equipment documentation or professional review where safety depends on the result.
Reviewed sources
- Department of Energy Style Guide: kilowatt and kilowatt-hour — U.S. Department of Energy; reviewed September 1, 2026.
- NIST Guide to the SI, Appendix B.9 — National Institute of Standards and Technology; reviewed September 1, 2026.
Method reviewed September 1, 2026. Scheduled review by 2028-08-31.