Electrical Engineering Calculator - Single & Three Phase with Units

Calculator

System type ?

Choose the type of circuit or supply.

Voltage basis ?

For three-phase, line voltage is line-to-line.

Three-phase connection ?

Only used for impedance/resistance conversion.

Enter any sensible pair such as voltage and current, voltage and power, power and power factor, or voltage and resistance. Leave unknowns blank.

Voltage V ?

Voltage

Current I ?

Current

Resistance / impedance Z or R ?

Resistance / impedance

Real power P ?

Real power

Apparent power S ?

Apparent power

Reactive power Q ?

Reactive power

Power factor PF ?

Dimensionless

Phase angle φ ?

Degrees

Voltage

—

Current

—

Resistance / impedance

—

Real power

—

Apparent power

—

Reactive power

—

VAr

Power factor

—

cos φ

Phase angle

—

degrees

Results and checks will appear here.

Electrical Cable Voltage Drop / Quick Sizing

Estimate voltage drop for copper or aluminium cables. This is a practical check tool, not a standards-compliant final cable-sizing engine.

System ?

Nominal voltage ?

Design current ?

Route length ?

Conductor material ?

Conductor size ?

Conductor operating temperature ?

Power factor ?

Cable reactance ?

Maximum voltage drop ?

Voltage drop

—

Voltage drop

—

Resistance used

—

Ω/km

Reactance used

—

Ω/km

Suggested size

—

mm²

Approx. current density

—

A/mm²

Cable voltage-drop results will appear here.

Mechanical / Cooling Calculator

Hydronic sensible cooling calculator using fluid flow, supply/return temperatures, density and specific heat capacity.

Sensible cooling capacity ?

Heat transfer rate

Flow rate ?

Volumetric flow

Fluid type ?

Cooling medium

Propylene glycol by volume ?

% v/v, selectable in 5% increments

Flow / supply temperature ?

Supply temperature

Return temperature ?

Return temperature

Cooling capacity

—

W / kW / MW

Flow rate

—

l/s / m³/h

ΔT

—

K / °C difference

Mean fluid temperature

—

°C

Specific heat capacity

—

kJ/kg·K

Density

—

kg/m³

Mass flow rate

—

kg/s

Fluid mix used

—

water / PG

Cooling results will appear here. Formula: sensible cooling capacity = density × volume flow × specific heat capacity × ΔT.

Pipe pressure drop

Uses Darcy-Weisbach with Swamee-Jain friction factor approximation.

Internal diameter ?

Pipe length ?

Pipe roughness ?

Pressure drop results will appear here.

Pipe quick sizing

Suggest pipe internal diameter from target velocity using the flow rate above.

Target velocity ?

Pipe sizing results will appear here.

Glycol freeze point estimate

Uses approximate concentration curves for glycol/water mixtures.

Freeze point estimate will appear here.

Viscosity estimate

Approximate dynamic and kinematic viscosity at mean fluid temperature.

Viscosity estimate will appear here.

Calculation basis

Core formula: Q = ρ × V̇ × cp × ΔT

Where Q is sensible cooling capacity in W, ρ is density in kg/m³, V̇ is volumetric flow in m³/s, cp is specific heat capacity in J/kg·K, and ΔT is the absolute difference between return and flow temperature in K.

The app estimates propylene glycol/water properties from built-in engineering approximation tables and interpolates by temperature and glycol percentage. This is suitable for early-stage calculation and checking, but final design should use the actual fluid manufacturer’s datasheet.

Symbols and units

Symbol	Meaning	Unit	Description
V / E	Voltage	Volts (V)	Electrical potential difference. In three-phase, normally line-to-line voltage unless phase voltage is selected.
I	Current	Amps (A)	Line current for single-phase and three-phase calculations.
R / Z	Resistance / impedance	Ohms (Ω)	Opposition to current. For AC this may be impedance rather than pure resistance.
P	Real power	Watts (W)	Useful power consumed by the load.
S	Apparent power	Volt-amps (VA)	Combination of real and reactive power. Used heavily for transformer, UPS and generator sizing.
Q	Reactive power	VAr	Power exchanged by inductive or capacitive parts of an AC load.
PF	Power factor	None	PF = P / S = cos φ. Values closer to 1 mean less reactive component.
φ	Phase angle	Degrees	Angle between voltage and current waveforms.

Engineering notes

DC/simple resistive: uses Ohm’s Law and power wheel formulas: V = I × R, P = V × I, P = I² × R, P = V² / R.

Single-phase AC: real power P = V × I × PF; apparent power S = V × I; reactive power Q = √(S² − P²).

Three-phase balanced AC: real power P = √3 × V_LL × I_L × PF; apparent power S = √3 × V_LL × I_L; reactive power Q = √3 × V_LL × I_L × sinφ.

Voltage basis: for three-phase, line voltage means line-to-line voltage. Phase voltage is line-to-neutral in star, or phase winding voltage in delta.

Mechanical cooling: the mechanical tab uses sensible heat only and estimates water/propylene glycol density and specific heat from built-in approximations based on glycol concentration and mean fluid temperature.

Limitations: this is a practical calculator, not a protection, cable sizing, discrimination, motor-start, harmonic, earthing, arc-flash, final cable sizing, installation rating, hydraulic pressure drop final design, pump selection, freezing-point final design or safety design tool.