EngineeringFormulaCalculators
Every EngineeringFormula calculator, organized by discipline.
01Ohm's Law CalculatorV = I × RElectricalV = I × RElectrical02Voltage Drop CalculatorVdrop = 2 × I × ρ × L / AElectricalVdrop = 2 × I × ρ × L / AElectrical03Wire Gauge CalculatorRequired Ampacity = I × k, then select smallest gauge with Ampacity ≥ Required AmpacityElectricalRequired Ampacity = I × k, then select smallest gauge with Ampacity ≥ Required AmpacityElectrical04Series & Parallel Resistance CalculatorRtotal = R1 + R2 + R3 + ...ElectricalRtotal = R1 + R2 + R3 + ...Electrical05Electrical Power CalculatorP = V × IElectricalP = V × IElectrical06Voltage Divider CalculatorVout = Vin × R2 / (R1 + R2)ElectricalVout = Vin × R2 / (R1 + R2)Electrical07Single-Phase Power CalculatorP = V × I × PFElectricalP = V × I × PFElectrical08Three-Phase Power CalculatorP = √3 × VL × IL × PFElectricalP = √3 × VL × IL × PFElectrical09Power Factor CalculatorPF = P / SElectricalPF = P / SElectrical10Capacitor Energy CalculatorU = 1/2 C V²ElectricalU = 1/2 C V²Electrical11Battery Life Calculatort = C / IElectricalt = C / IElectrical12Amp Hour CalculatorAh = Wh / VElectricalAh = Wh / VElectrical13Inductor CalculatorXL = 2 pi f LElectricalXL = 2 pi f LElectrical14RC Time Constant Calculatorτ = R × CElectricalτ = R × CElectrical15Watts to Amps CalculatorI = P / VElectricalI = P / VElectrical16kWh CalculatorDaily Energy = P × h / 1000ElectricalDaily Energy = P × h / 1000Electrical17Resistor Color Code CalculatorR = significant digits × multiplierElectricalR = significant digits × multiplierElectrical18LED Resistor CalculatorV_R = V_s − nV_f − V_driverElectricalV_R = V_s − nV_f − V_driverElectrical19Circuit Breaker Size CalculatorIreq = Inc + 1.25 × Ic, then choose the next standard breaker size ≥ IreqElectricalIreq = Inc + 1.25 × Ic, then choose the next standard breaker size ≥ IreqElectrical20Fuse Size CalculatorIreq = k × I, then choose the next standard fuse rating ≥ Ireq (k = 1.25 continuous, 1.0 intermittent)ElectricalIreq = k × I, then choose the next standard fuse rating ≥ Ireq (k = 1.25 continuous, 1.0 intermittent)Electrical21Diode CalculatorR = (V_s − V_F) / IElectricalR = (V_s − V_F) / IElectrical22Zener Diode CalculatorR_S ≤ (V_in,min − V_Z) / (I_L,max + I_Z,min)ElectricalR_S ≤ (V_in,min − V_Z) / (I_L,max + I_Z,min)Electrical23PCB Trace Width CalculatorW = [ I / (k ΔT^0.44) ]^(1/0.725) / tElectricalW = [ I / (k ΔT^0.44) ]^(1/0.725) / tElectrical24Torque CalculatorT = F × rMechanicalT = F × rMechanical25Bolt Torque CalculatorT = K × D × FMechanicalT = K × D × FMechanical26Weld Strength Calculatorte = 0.707 × sMechanicalte = 0.707 × sMechanical27Shaft Diameter Calculatord = (16T / (pi tau_d))^(1/3)Mechanicald = (16T / (pi tau_d))^(1/3)Mechanical28Bearing Load CalculatorP = max(Fr, XFr + YFa)MechanicalP = max(Fr, XFr + YFa)Mechanical29Torque Wrench CalculatorE_eff = E × cos θMechanicalE_eff = E × cos θMechanical30Pulley Ratio Calculatori = D2 / D1Mechanicali = D2 / D1Mechanical31Belt Speed Calculatorv = π × D × nMechanicalv = π × D × nMechanical32Belt Length CalculatorL = 2sqrt(C² - e²) + d(π - 2β)/2 + D(π + 2β)/2MechanicalL = 2sqrt(C² - e²) + d(π - 2β)/2 + D(π + 2β)/2Mechanical33Chain Length CalculatorL = 2C/p + (N1 + N2)/2 + (N2 - N1)^2 / (4pi^2 C/p)MechanicalL = 2C/p + (N1 + N2)/2 + (N2 - N1)^2 / (4pi^2 C/p)Mechanical34Sprocket Calculatori = N2 / N1Mechanicali = N2 / N1Mechanical35Thread Pitch CalculatorPmm = 25.4 / TPIMechanicalPmm = 25.4 / TPIMechanical36Spring Compression Calculatork = G d^4 / (8 D^3 Na)Mechanicalk = G d^4 / (8 D^3 Na)Mechanical37Flywheel Energy CalculatorE = 1/2 I omega^2MechanicalE = 1/2 I omega^2Mechanical38Compression Ratio CalculatorCR = (Vs + Vc) / VcMechanicalCR = (Vs + Vc) / VcMechanical39Engine Displacement CalculatorV = n π B² S / 4MechanicalV = n π B² S / 4Mechanical40Gear Ratio Calculatori = N2 / N1Mechanicali = N2 / N1Mechanical41Horsepower CalculatorHP = P(W) / 745.7MechanicalHP = P(W) / 745.7Mechanical42Stress Calculatorσ = F / AMechanicalσ = F / AMechanical43Strain Calculatorε = ΔL / L0Mechanicalε = ΔL / L0Mechanical44Young's Modulus CalculatorE = σ / εMechanicalE = σ / εMechanical45Force CalculatorF = m aEngineering MechanicsF = m aEngineering Mechanics46Net Force CalculatorFnet = ΣFEngineering MechanicsFnet = ΣFEngineering Mechanics47Gravitational Force CalculatorF = G m1 m2 / r²Engineering MechanicsF = G m1 m2 / r²Engineering Mechanics48Kinetic Energy CalculatorKE = 1/2 m v²Engineering MechanicsKE = 1/2 m v²Engineering Mechanics49Impact Force CalculatorFavg = (1/2 m v²) / dEngineering MechanicsFavg = (1/2 m v²) / dEngineering Mechanics50Spring Force CalculatorF = k xEngineering MechanicsF = k xEngineering Mechanics51Centripetal Force CalculatorFc = m v² / rEngineering MechanicsFc = m v² / rEngineering Mechanics52Potential Energy CalculatorPE = m g hEngineering MechanicsPE = m g hEngineering Mechanics53Acceleration Calculatora = (v - u) / tEngineering Mechanicsa = (v - u) / tEngineering Mechanics54Velocity Calculatorv = Δx / tEngineering Mechanicsv = Δx / tEngineering Mechanics55Free Fall Calculatorh = 1/2 g t²Engineering Mechanicsh = 1/2 g t²Engineering Mechanics56Momentum Calculatorp = m × vEngineering Mechanicsp = m × vEngineering Mechanics57Projectile Motion CalculatorT = 2 v₀ sin θ / gEngineering MechanicsT = 2 v₀ sin θ / gEngineering Mechanics58Terminal Velocity Calculatorv = √(2mg / (Cd ρ A))Engineering Mechanicsv = √(2mg / (Cd ρ A))Engineering Mechanics59Board Foot CalculatorBF = T(in) × W(in) × L(ft) / 12Civil & StructuralBF = T(in) × W(in) × L(ft) / 12Civil & Structural60Beam Deflection Calculatorδ = P L³ / (48 E I)Civil & Structuralδ = P L³ / (48 E I)Civil & Structural61Beam Reaction CalculatorRA = P(L − a)/L; RB = Pa/LCivil & StructuralRA = P(L − a)/L; RB = Pa/LCivil & Structural62Section Modulus CalculatorS = I / cCivil & StructuralS = I / cCivil & Structural63Bending Stress Calculatorσ = M / SCivil & Structuralσ = M / SCivil & Structural64Area Moment of Inertia CalculatorIx = b h³ / 12; Iy = h b³ / 12Civil & StructuralIx = b h³ / 12; Iy = h b³ / 12Civil & Structural65Column Slenderness Ratio Calculatorλ = KL / rCivil & Structuralλ = KL / rCivil & Structural66Retaining Wall CalculatorRows = ⌈H / h⌉Civil & StructuralRows = ⌈H / h⌉Civil & Structural67Deck CalculatorRows = ⌈(W + g) / (bw + g)⌉Civil & StructuralRows = ⌈(W + g) / (bw + g)⌉Civil & Structural68Rafter Length CalculatorL = (R + O − t/2) × √(1 + (r/R)²)Civil & StructuralL = (R + O − t/2) × √(1 + (r/R)²)Civil & Structural69Fence CalculatorSections = ⌈L / s⌉Civil & StructuralSections = ⌈L / s⌉Civil & Structural70Tile CalculatorColumns = ⌈(L + g) / (tl + g)⌉Civil & StructuralColumns = ⌈(L + g) / (tl + g)⌉Civil & Structural71Siding CalculatorGross Area = P × H + AgCivil & StructuralGross Area = P × H + AgCivil & Structural72Drywall CalculatorWall Area = P × HCivil & StructuralWall Area = P × HCivil & Structural73Paint CalculatorNet Area = (P × H) − AoCivil & StructuralNet Area = (P × H) − AoCivil & Structural74Stair CalculatorN = max(1, round(R / rh))Civil & StructuralN = max(1, round(R / rh))Civil & Structural75Roof Pitch CalculatorSlope = r / RCivil & StructuralSlope = r / RCivil & Structural76Roofing Shingle CalculatorPitch Factor = √(1 + (X/12)²)Civil & StructuralPitch Factor = √(1 + (X/12)²)Civil & Structural77Gravel CalculatorVolume = L × Wd × DCivil & StructuralVolume = L × Wd × DCivil & Structural78Paver CalculatorN = ⌈Columns × Rows × (1 + W%)⌉Civil & StructuralN = ⌈Columns × Rows × (1 + W%)⌉Civil & Structural79Concrete CalculatorVolume (rectangular) = L × Wd × DCivil & StructuralVolume (rectangular) = L × Wd × DCivil & Structural80Concrete Mix Ratio CalculatorVolume with waste = Vw × (1 + W%)Civil & StructuralVolume with waste = Vw × (1 + W%)Civil & Structural81Rebar Weight CalculatorUnit weight = π × d² × ρ / 4Civil & StructuralUnit weight = π × d² × ρ / 4Civil & Structural82Footing Size CalculatorAdjusted load = P × (1 + a)Civil & StructuralAdjusted load = P × (1 + a)Civil & Structural83Steel Weight CalculatorWeight (round bar) = π × (D / 2)² × L × ρCivil & StructuralWeight (round bar) = π × (D / 2)² × L × ρCivil & Structural84Reynolds Number CalculatorRe = ρ v D / μFluid MechanicsRe = ρ v D / μFluid Mechanics85Bernoulli Equation Calculatorp1 = p2 + 1/2 ρ (v2² - v1²) + ρ g (z2 - z1)Fluid Mechanicsp1 = p2 + 1/2 ρ (v2² - v1²) + ρ g (z2 - z1)Fluid Mechanics86Hydrostatic Pressure Calculatorp = ρ g hFluid Mechanicsp = ρ g hFluid Mechanics87Buoyant Force CalculatorF_B = rho g V_dFluid MechanicsF_B = rho g V_dFluid Mechanics88Pump Hydraulic Power CalculatorP_h = rho g Q HFluid MechanicsP_h = rho g Q HFluid Mechanics89Orifice Flow CalculatorQ = C_d A √(2 Delta p / rho)Fluid MechanicsQ = C_d A √(2 Delta p / rho)Fluid Mechanics90Venturi CalculatorQ = Cd A2 sqrt(2 Delta p / (rho (1 - beta^4)))Fluid MechanicsQ = Cd A2 sqrt(2 Delta p / (rho (1 - beta^4)))Fluid Mechanics91Continuity Equation CalculatorA1 = A2 v2 / v1Fluid MechanicsA1 = A2 v2 / v1Fluid Mechanics92Flow Rate CalculatorQ = A vFluid MechanicsQ = A vFluid Mechanics93CFM CalculatorCFM = (W × H) vFluid MechanicsCFM = (W × H) vFluid Mechanics94Duct Size CalculatorA = Q / vFluid MechanicsA = Q / vFluid Mechanics95Pipe Size CalculatorA = Q / vFluid MechanicsA = Q / vFluid Mechanics96Manning Equation CalculatorA = b × yFluid MechanicsA = b × yFluid Mechanics97Static Pressure CalculatorTESP = |Ps| + |Pr|Fluid MechanicsTESP = |Ps| + |Pr|Fluid Mechanics98Air Changes per Hour CalculatorV = L x W x HFluid MechanicsV = L x W x HFluid Mechanics99Water Pressure CalculatorP = ρ g hFluid MechanicsP = ρ g hFluid Mechanics100Pipe Volume CalculatorV = π d² L / 4Fluid MechanicsV = π d² L / 4Fluid Mechanics101Pressure Drop CalculatorΔp = f (L/D) (ρv²/2) + K (ρv²/2) + ρ g ΔzFluid MechanicsΔp = f (L/D) (ρv²/2) + K (ρv²/2) + ρ g ΔzFluid Mechanics102Carnot Efficiency Calculatorη = 1 − Tc / ThThermodynamicsη = 1 − Tc / ThThermodynamics103Convective Heat Transfer CalculatorQ̇ = h A ΔTThermodynamicsQ̇ = h A ΔTThermodynamics104Heat Energy CalculatorQ = m c ΔTThermodynamicsQ = m c ΔTThermodynamics105Specific Heat Calculatorc = Q / (m ΔT)Thermodynamicsc = Q / (m ΔT)Thermodynamics106Heat Conduction CalculatorQ̇ = k A ΔT / LThermodynamicsQ̇ = k A ΔT / LThermodynamics107Thermal Conductivity Calculatork = Q̇ L / (A ΔT)Thermodynamicsk = Q̇ L / (A ΔT)Thermodynamics108Thermal Expansion CalculatorΔL = α L₀ (Tf − Ti)ThermodynamicsΔL = α L₀ (Tf − Ti)Thermodynamics109Ideal Gas Law CalculatorP = n R T / VThermodynamicsP = n R T / VThermodynamics110Thermal Resistance CalculatorR = ΔT / Q̇ThermodynamicsR = ΔT / Q̇Thermodynamics111U-Value CalculatorRlayer = L / kThermodynamicsRlayer = L / kThermodynamics112Heat Loss CalculatorQtrans = Σ(U × A × ΔT)ThermodynamicsQtrans = Σ(U × A × ΔT)Thermodynamics113HVAC Load CalculatorQenv = Σ(U × A × ΔT)ThermodynamicsQenv = Σ(U × A × ΔT)Thermodynamics114Refrigerant Charge CalculatorLine charge = charged length delta × charge rateThermodynamicsLine charge = charged length delta × charge rateThermodynamics115BTU CalculatorArea = L × WdThermodynamicsArea = L × WdThermodynamics116Dew Point Calculatorγ = (a × Tc) / (b + Tc) + ln(RH / 100)Thermodynamicsγ = (a × Tc) / (b + Tc) + ln(RH / 100)Thermodynamics117Wind Chill CalculatorWC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T V^0.16ThermodynamicsWC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T V^0.16Thermodynamics