A correct equation can still answer the wrong physical question. OhmCalc proves only that four positive values satisfy the ideal resistive DC equations after exact unit normalization. It cannot inspect how a real component or circuit behaves outside that model.
One operating point is not a full characteristic
Real resistance may vary with temperature, voltage, current, light, mechanical state, or manufacturing tolerance. A value that fits one measurement does not guarantee the same ratio elsewhere.
AC and reactive circuits need more information
Capacitors and inductors introduce frequency-dependent reactance and phase. RMS, peak, average, and instantaneous quantities are not interchangeable. A scalar R and the DC equations cannot replace impedance or waveform analysis.
Calculated power is not a component rating
If the arithmetic gives 0.25 W, that does not automatically make a 0.25 W resistor suitable. Ambient temperature, enclosure, pulse duration, derating, ventilation, maximum voltage, tolerance, and failure mode can require a different choice.
Electrical safety is outside the formula
Shock, fire, insulation, creepage, clearance, conductor size, protective devices, grounding, and legal compliance require system context and qualified judgment. Never treat a calculator output as permission to work on energized equipment.