Engineering Formula Guides
Problem-first formula explainers paired with live calculators, worked examples, units, assumptions and links to deeper OneCalcApp engineering tools.
Voltage Drop Formula
Voltage drop is the reduction in voltage along a conductor caused by current flowing through its impedance. For a simple DC or single-phase resistive circuit, the round-trip conductor resistance is the key input.
Torque Formula
Torque is the turning effect of a force about an axis. It depends on the force magnitude, the distance from the axis and the angle between the force and lever arm.
Beam Deflection Formula
Beam deflection is the displacement of a beam from its unloaded position. Classical elastic formulas depend strongly on span length, loading, Young's modulus and the second moment of area.
Moment of Inertia Formula
In beam and structural calculations, the area moment of inertia (second moment of area) describes how cross-sectional area is distributed about an axis. A larger I generally means greater bending stiffness for the same material.
Reynolds Number Formula
Reynolds number is a dimensionless ratio comparing inertial and viscous effects in a flowing fluid. It is widely used to assess whether internal flow is broadly laminar, transitional or turbulent.
Bending Stress Formula
The elastic flexure formula relates normal bending stress to bending moment, distance from the neutral axis and the section's second moment of area.
Strain Formula
Engineering strain measures deformation relative to an original gauge length. Because it is a ratio of two lengths, strain itself is dimensionless.
Power Formula
Power is the rate at which energy is transferred or work is done. The correct equation depends on whether the system is electrical, mechanical or another energy domain.
How these guides are structured
Each page starts with the governing equation, defines every symbol and unit, shows the calculation procedure, includes solved examples and common mistakes, and provides a live calculator for a representative engineering case. Links to the deeper OneCalcApp calculator are included where a dedicated tool already exists.