The formula
Continuous current = Capacity (Ah) × C rating. A 5000 mAh (5 Ah) pack rated 50 C claims 250 A continuous.
What C really is
C expresses discharge rate relative to capacity: 1 C empties the pack in one hour, 50 C theoretically in ~72 seconds. It is a label figure from the manufacturer — real sustained capability depends on cell quality, temperature and age.
Why labels overshoot
Marketing C ratings on many packs exceed what the cells can actually sustain. Treat the computed current as a ceiling derived from the label, and watch pack temperature on the first runs.
Where it is used
The C Rating Calculator does the conversion; cross-check the result against your ESC sizing with the ESC Amp Calculator.