Electrical Engineering Calculators



The most common used electrical formulas - Ohms Law and combinations

This app contains all the Electrical Engineering calculations and conversions including Voltage, Current, Power, Efficiency, Resistor/Capacitor/Inductor combinations, Resonant Frequency, Reactance.

Electrical Calculator Online

Common electrical units used in formulas and equations are:

  • Volt - unit of electrical potential or motive force - potential is required to send one ampere of current through one ohm of resistance
  • Ohm - unit of resistance - one ohm is the resistance offered to the passage of one ampere when impelled by one volt
  • Ampere - units of current - one ampere is the current which one volt can send through a resistance of one ohm
  • Watt - unit of electrical energy or power - one watt is the product of one ampere and one volt - one ampere of current flowing under the force of one volt gives one watt of energy
  • Volt Ampere - product of volts and amperes as shown by a voltmeter and ammeter - in direct current systems the volt ampere is the same as watts or the energy delivered - in alternating current systems - the volts and amperes may or may not be 100% synchronous - when synchronous the volt amperes equals the watts on a wattmeter - when not synchronous volt amperes exceed watts - reactive power
  • kiloVolt Ampere - one kilovolt ampere - kVA - is equal to 1000 volt amperes
  • Power Factor - ratio of watts to volt amperes

Electrical Potential - Ohm's Law

All About Circuits is one of the largest online electrical engineering communities in the world with over 300K engineers, who collaborate every day to innovate, design, and create. Calculators for Electrical Engineering & Electronics. All Electrical Engineering Formulas List. Cable Length from Sag, Span. Formula: L = S + ((8. d 2) / (3. S)) Where, L = Cable Length S = Cable Span d = Cable Sag. Using this Online Electrical Calculator the parallel Capacitors calculation in a circuit is made easier here. Related Calculator: Parallel Capacitor Calculator; Horsepower (HP. Find Electrical Engineering Calculator at CalcTown. Use our free online app Electrical Engineering Calculator to determine all important calculations with parameters and constants. All About Circuits is one of the largest online electrical engineering communities in the world with over 300K engineers, who collaborate every day to innovate, design, and create. Calculators for Electrical Engineering & Electronics.

Ohm's law can be expressed as:

U = R I (1a)

U = P / I (1b)

U = (P R)1/2 (1c)

Electric Current - Ohm's Law

I = U / R (2a)

I = P / U (2b)

I = (P / R)1/2 (2c)

Electric Resistance - Ohm's Law

R = U / I (3a)

R = U2/ P (3b)

R = P / I2 (3c)

Example - Ohm's law

A 12 volt battery supplies power to a resistance of 18 ohms.

I = (12 V) / (18 Ω)

= 0.67 (A)

Electric Power

P = U I (4a)

P = R I2 (4b)

P = U2/ R (4c)

where

P = power (watts, W, J/s)

U = voltage (volts, V)

I = current (amperes, A)

R = resistance (ohms, Ω)

Electric Energy

Electric energy is power multiplied with time:

W = P t (5)

where

W = energy (Ws, J)

t = time (s)

Alternative - power can be expressed

P = W / t (5b)

Power is consumption of energy by consumption of time.

Example - Energy lost in a Resistor

A 12 V battery is connected in series with a resistance of 50 ohm. The power consumed in the resistor can be calculated as

P = (12 V)2 / (50 ohm)

= 2.9 W

The energy dissipated in 60 seconds can be calculated

W = (2.9 W) (60 s)

= 174 Ws, J

= 0.174 kWs

= 4.8 10-5 kWh

Example - Electric Stove

An electric stove consumes 5 MJ of energy from a 230 V power supply when turned on in 60 minutes.

The power rating - energy per unit time - of the stove can be calculated as

P = (5 MJ) (106 J/MJ) / ((60 min) (60 s/min))

= 1389 W

= 1.39 kW

The current can be calculated

I = (1389 W) / (230 V)

= 6 ampere

Electrical Motors

Electrical Engineering Calculators

Electrical Motor Efficiency

μ = 746 Php / Pinput_w (6)

where

μ = efficiency

Php = output horsepower (hp)

Pinput_w = input electrical power (watts)

or alternatively

μ = 746 Php / (1.732 V I PF) (6b)

Electrical Motor - Power

P3-phase = (U I PF 1.732) / 1,000 (7)

where

P3-phase = electrical power 3-phase motor (kW)

PF = power factor electrical motor

Electrical Motor - Amps

I3-phase = (746 Php) / (1.732 VμPF) (8)

where

I3-phase = electrical current 3-phase motor (amps)

PF = power factor electrical motor

Related Topics

  • Electrical - Electrical units, amps and electrical wiring, wire gauge and AWG, electrical formulas and motors

Related Documents

  • 12 Volt Current and Maximum Wire Length - Maximum copper wire length with 2% voltage drop
  • Abbreviations According the International Electrotechnical Commission - Conforming abbreviations according IEC
  • Aluminum Conductor Characteristics - Characteristics of all-aluminum conductor (AAC)
  • Charging Electrical Vehicles - Voltage, Amps and Power - EV - Electrical Vehicle - Charging Stations - Power vs. Amps and Voltage - AC vs. DS - Single Phase vs. Three Phase
  • Copper Wire - Electrical Resistance - Gauge, weight, circular mils and electrical resistance
  • Electric Circuit Diagram - Template - Use Google Drive to make online shareable electric circuit diagrams
  • Electrical Equipment and typical Power Consumption - Typical power consumption and running time for some common electrical equipment
  • Electrical Units - Definition of common electrical units - like Ampere, Volt, Ohm, Siemens
  • Electromotive Force - e.m.f - Change in electrical potential between two points
  • Lead Acid Batteries - Specific gravity and charge of lead acid batteries - temperature and efficiency
  • Max Amps in Copper and Aluminum Wire - Maximum current in copper and aluminum wire
  • Ohm's Law - Voltage, current and resistance
  • Relative vs. Absolute Voltage - Electric circuits and the voltage at any point
  • Resistance and Conductance - The reciprocal of electrical resistance is conductance
  • Resistivity and Conductivity - Temperature Coefficients for Common Materials - Resistivity, conductivity and temperature coefficients for some common materials as silver, gold, platinum, iron and more
  • Resistors - Color Codes Calculator - Color codes for fixed resistors - values and tolerances - online calculator
  • Single Phase Power Equations - Single phase electrical power equations
  • Single vs. Three Phase AC - Amperage - Convert between single phase (120, 240 and 480 Voltage) and three phase (240 and 480 Voltage)
  • Three-Phase Power Equations - Electrical 3-phase equations
  • Voltage by Country - Typical voltages and frequencies used for domestic appliances

Cable Length from Sag, Span

Formula:


L = S + ((8 * d2) / (3 * S))


Where,
L = Cable Length
S = Cable Span
d = Cable Sag

Related Calculator:

Spring Resonant Frequency

Formula:

fres= (1/2)* √(k/M)


Where,
fres = Spring Resonance
k = Spring Constant
M = Spring Mass

Related Calculator:


Solenoid Coil Electromagnetic Force

Formula:


F = (n x i)2 x magnetic constant x a / (2 x g2)
Where,
F = Force,
i = Current,
g = Length of the gap between the solenoid and a piece of metal,
a = Area
n = Number of turns,
Magnetic constant = 4 x PI x 10-7.

Related Calculator:

Capacitor Energy (E) and RC Time Constant

Best Calculator For Electronics

Formula:

E = (V² x C) / 2
T = R x C


Where,
E =Stored Energy (Joules),
T = Time Constant (S),
V = Volatge (V) ,
C = Capacitance (uF),
R = Load Resistance (Ohms).

Related Calculator:

Electrician Calculator Free

Physical Properties of Coil / Material

Formula Used:


T = bl / d
n = Turns/ T
cd = (2 x n x d) + bd
r = (n x d + bd) / 2
a = PI x r x r
L = (2 x PI x r x n) / 1000
rpm = .0333 *((0.812/2)*(0.812/2))/((d/2)*(d/2))
R = rpm x L
V = R x I
P = V x I
Where,
T = Turns per winding,
bl = Length of Bobbin,
d = Wire Diameter,
n = Number of windings,
cd = Outer diameter of coil,
bd = Diameter of Bobbin,
r = radius of middle of coil,
a = Cross sectional area,
L = Total Length,
rpm = Resistance/meter,
R = Resistance,
V = Voltage at Rated Current,
I = Current,
P = Power at Rated Current,

Related Calculator:

Air Core Coil Inductance

Formula:


Inductance = ((d2) x (n2)) / (18d + 40l)
Where,
d = Coil Diameter,
l = Coil Length,
n = Number of turns.

Related Calculator:

Parallel Resistor

Formula Used:


Rp = 1 / ((1/R1) + (1/R2))
Where,
Rp = Total Parallel Resistance
R1 & R2 = Resistors connected in parallel

Related Calculator:

Straight Wire Inductance / Inductor

Formula:


L= 0.00508 x a x (log(2 x a/d)-0.75)
Where,
L = Inductance,
a,d = Length & Diameter of the wire,

Related Calculator:

8051 PIC Microcontroller (UC) Time Delay

Electrical Engineering Calculators

Formula Used:


TIC12 = 1 / (mhz / 12)TIC6 = 1 / (mhz / 6)
8-bit Timer Counter Maximum Run-Time for 12 clock = TIC12 * 256 / 1000
8-bit Timer Counter Maximum Run-Time for 6 clock = TIC6 * 256 / 1000
16-bit Timer Counter Maximum Run-Time for 12 clock = TIC12 * 65536 / 1000
16-bit Timer Counter Maximum Run-Time for 6 clock = TIC6 * 65536 / 1000
8-Bit DRT Reload Value for 12 clock = 256 -(DRT / TIC12 * 1000)
8-Bit DRT Reload Value for 6 clock = 256 -(DRT / TIC6 * 1000)
16-Bit DRT Reload Value for 12 clock = 65536 -(DRT / TIC12 * 1000)
16-Bit DRT Reload Value for 6 clock = 65536 -(DRT / TIC6 * 1000)

Related Calculator:

Parallel Resistance of Electronic Circuit

Formula :


Where R1,R2,...Rn are the individual resistor values
Rtotal is the total resistance value in parallel

Related Calculator:

Series Resistor / Resistance

Formula:


R=R1+R2+R3+.......


Where,
R = Total Resistors value
R1 = Individual Resistors value
R2 = Individual Resistors value
R3 = Individual Resistors value

Related Calculator:

Microstrip Transmission Lines Impedance (Z0)

Formula:


Related Calculator:

Electrical Admittance (Y)

Formula:

Related Calculator:

Series Capacitor / Capacitance

Formula :
1/CTotal = 1/C0 + 1/C1 + 1/C2 + .... + 1/Cn

Where,C0,C1,..,Cn are the individual capacitors values
CTotal is the total capacitance value of an electrical circuit

Related Calculator:

Parallel Capacitor / Capacitance

Formula :
CTotal = C1 + C2 + C3 + .... + Cn

Where,C1,C2,..,Cn are the individual capacitors values
CTotal is the total capacitors value in parallel
Using this Online Electrical Calculator the
parallel Capacitors calculation in a circuit is made easier here.

Related Calculator:

Horsepower (HP) and Watts Conversion

Formula:


Horsepower (HP) =W/HP

Where,
W = Power in wattsHP = Value of one HP
1 Electrical HP = 746 watts
1 Mechanical HP = 745.69987 watts
1 Metric HP = 735.49875 watts

Related Calculator:

Power Factor for AC

3 Phase Motor Cost Calculator

Formula:


Power factor = kW/√ (kW)2 + (kVAr)2

Where,
kW = Real Power
kVAr = Reactive Power

Related Calculator:

Three Phase Transformer Capacity

Formula:

V = (k x 1000) / (A x Ph)
A = (k x 1000) / (V x Ph)
k = (Ph x V x A) / 1000


Where,
V = Volt
A = Amps
k = kVA
Ph = 3 phase (√3 = 1.732050808)

Related Calculator:

Specific Work of Gas Turbine

Formula:

w = K / ((K - 1) * R * T1 * [1 - ((p2 / p1)((K-1)/K))])


Where,
w = Specific Work Gas Turbine
K = Ratio Specific Heat Air
R = Individual Gas Constant
T1 = Absolute Temperature
p1 = Primary Pressure
p2 = Secondary Pressure

Related Calculator:

3 Phase Power by Two Wattmeters Method

Formula:


P = ( V12 * I2 * cos ( 30 + θ ) ) + ( V13 * I3 * cos ( 30 - θ ) )


Where,
P = Three Phase Power
V12 , V13 = Voltage
I2, I3 = Current
θ = Displacement Angle
cos = Cosine

Related Calculator:

Specific Work

Formula:

w = (p1 - p2) / ρ
t = (p2 - p1) / ρ


Where,
w = Specific Work of Pump
t = Specific Work of Turbine
p1 = Primary Pressure
p2 = Secondary Pressure
ρ = Density

Related Calculator:

AVR Timer


Formula:

f = cf / p
o = ttt / tr2
rtt = t - (o * tr2)
rt = ttt / f
nf = f / ttt


Where,
f = Frequency
cf = System Clock Frequency
p = Prescaler Clock Value
o =Overflow Count
tr = Timer Resolution
ttt = Total Timer Ticks
rtt = Remainder Timer Ticks
rt = Real Time
nf = New Frequency

Related Calculator:

Young's Modulus Spring Resonant Frequency

Formula:

fres = (d / (9* D2 * nf)) * √(G / ρ)


Where,
fres = Spring Resonant Frequency
d = Wire Diameter
D = spring Diameter
nf = Total Number of Coils
G = Youngs Modulus of Material
ρ = Material Density

Related Calculator:

Gearbox Ratio

Formula:

GF = (eRPM * h * 0.002975) / a
MPH = GF / GR


Where,
GF = Gear Factor
GR = Gear Ratio
eRPM = Engine RPM (Revolution per Minute)
h = Tire Height
a = Axle Ratio
MPH = Miles per Hour

Related Calculator:

Power Consumption mAh Calculator

Formula:

b = (c / h) * 0.70


Where,
b = Average Current Consumption
c = Battery Capacity
h = Estimated Hours

Related Calculator:

Electricity Cost

Formula:

Energy Consumed per Day = (p × h) / 1000
Energy Consumed per Month = ((p × h) / 1000) × 30
Energy Consumed per Year = ((p × h) / 1000) × 365
Electricity Cost per Day = ((p × h) / 1000) × r
Electricity Cost per Month =(((p × h) / 1000) × 30) × r
Electricity Cost per Year = (((p × h) / 1000) × 365) × r


Where,
p = Power Consumption
h = Hours of Use per Day
r = Electricity Cost per Unit

Related Calculator:

Wire Diameter

Formula:

D = 2 × √(A / π)


Where,
D = Wire Diameter
A = Area

Related Calculator:

Wire Gauge

Formula:

Wire Diameter in AWG = -10 - 20 × log(d)


Where,
d = Wire Diameter
g = Diameter of Wire in Gauge

Related Calculator:

Electric Potential Energy

Formula:



Where,
V = Electric Potential
qN = Charge
ε0 = Permittivity(8.8541878176e-12 F/m)
rN = Point Distant

Related Calculator:

Transformer Current

Formula:

I = P / V


Where,
I = Current
P = Power Rating
V = Voltage

Related Calculator:

Transformer Primary Conductor Size

Formula:

δ = I / A


Where,
δ = Conductor Size
I= Current
A = Current density

Related Calculator:

Number of Turns in a Transformer Coil

Formula:

Te = (1/(4.44 × F × M × A))
T = Te × V

Where,
Te = Turns per Volts
T = Total Number of Turns
M = Magnetic flux
A = Area of Core
F = Operating Frequency
V = Voltage

Related Calculator:

Transformer Wire Length

Formula:

Total Wire Length = Number of Turns × Perimeter of Bobbin

Related Calculator:

Volume of Conductor

Formula:

Volume of Conductor = Area × Length

Related Calculator:

Weight of Transformer Windings

Formula:

Weight of Windings(kg) = Density × Volume(m3)

Related Calculator:

NE555 Timer Astable Circuit

Formula:


f = 1.44 / ((R1 + 2(R2)) × C)
THigh = 0.693 × (R1 + R2) × C
Tlow = 0.693 × R2 × C
d = ( THigh / ( THigh + l )) × 100


Where,
R1 = Resistor 1
R2 = Resistor 2
C = Capacitor
d = Duty Cycle
f = Frequency
THigh = Time High
Tlow = Time Low

Related Calculator:

Electrical

Electrostatic

Electrical Engineering Calculator Download

Formula:

p = ε0 × e2 / 2


Where,
p = Electrostatic Pressure
e = Electric Field
ε0 = Electric Constant(8.854×10-12)

Related Calculator:

Real and Reactive Power

Formula:

For Single Phase
t = v × i × cos(p)
r = v × i × sin(p)

For Three Phase
t = √3 × v × i × cos(p)
r = √3 × v × i × sin(p)


Where,
t = Real power
r = Reactive power
v = Voltage
i = Current
p = Phase Angle

Related Calculator:

DC Power

Formula:

P = V × I
V = P / I
I = P / V


Where,
P = Power
V = Voltage
I = Current

Related Calculator:

AC Power

Formula:

For Single Phase
P = V × I × cos(θ)
V = P / (I × cos(θ)
I = P / (V × cos(θ)

For Three Phase
P = √3 × V × I × cos(θ)
V = P / (3 × I × cos(θ)
I = P / (3 × V × cos(θ)


Where,
P = Power
θ = Power Factor Angle
V = Voltage
I = Current

Related Calculator:

Power Consumption South Africa

Formula:

p = (e × t) / 1000


Where,
p = Power Consumption
e = Electricity Usage
t = Total Usage Time

Related Calculator:

Copper Loss

Formula:

l = (a2 × b) + (c2 × d)


Where,
l = Copper Loss
a = Primary Winding Current
b = Primary Winding Ohmic Resistance
c = Secondary Winding Current
d = Secondary Winding Ohmic Resistance

Related Calculator:

Total Luminous Flux

Formula:

Ω = 2π(1-Cosθ)
F = ΩIv


Where,
Iv = Maximum Luminous Intensity
θ = Cone Full Angle
Ω = Equivalent Solid Angle
F = Total Luminous Flux

Related Calculator:

Coaxial Cable Impedance

Formula:

Z = (138 × log10 (d1 / (d2)) / √(R)
F = 11.8 / (√(R) × π × ((d1 + d2) / 2))
T =( (7.354 × R) / (log10(d1 / d2)))/0.3048
D = (140.4 × log10(d1 / d2))/0.3048
V = (1 / √ (R)) × 100


Where,
Z = Impedance
d1 = Dielectric Outer Diameter
d2 = Inner Conductor Diameter
R = Dielectric Constant
F = Cutoff Frequency
T = Capacitance
D = Inductance
V = Velocity of Propagation

Related Calculator:


Top Calculators

Popular Calculators

Top Categories