JUJUMI Engineering Calculators
Free, accurate, instant online engineering calculation platform covering Mechanical, Electrical, Civil engineering and unit conversion — 141 tools, formulas per ISO / AGMA / ASME. Live search and category filters built in.
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Popular Tools
Gear Ratio
Compute the gear ratio between driver and driven gears, outp
Open →Ohm's Law
Given any two of voltage U, current I, resistance R, solve t
Open →Bearing Life
Compute rated bearing life L10 (10⁶ rev) and L10h (hours). O
Open →Length Converter
Instantly convert Length between SI and common engineering u
Open →Mechanical Engineering 78
Gears & Transmission15
Gear Ratio
Compute the gear ratio between driver and driven gears, outp
Open →Gear Module & Pitch
Compute pitch diameter D, addendum da, root df, circular pit
Open →Bevel Gear Dimensions
Compute pitch cone angle γ, equivalent teeth Zv, cone distan
Open →Gear Undercut & Profile Shift
Determine the minimum teeth Zmin to avoid undercut and the m
Open →Standard Spur Gear Size
Compute pitch, addendum, base diameters, centre distance, ci
Open →Planetary Gear Ratio
Compute the ratio, output speed and output torque of a singl
Open →Gear Contact Stress (Hertz)
Estimate the gear tooth contact fatigue stress σ_H with a si
Open →Gear Bending Stress (Lewis)
Estimate root bending fatigue stress σ_F via the Lewis formu
Open →Worm Gear Drive
Compute the ratio, output speed, efficiency η and output tor
Open →Rack & Pinion Displacement
Compute the linear travel per revolution and total displacem
Open →Chain Drive Length
Estimate chain link count Lp and actual length L from pitch
Open →Synchronous Belt Length
Estimate synchronous belt pitch length from pulley pitch dia
Open →Compound Gear Train
Compute the overall ratio of a two-stage compound train i =
Open →Internal Gear Dimensions
Compute pitch, addendum and root diameters of an internal ge
Open →Ball Screw Travel & Torque
Compute linear travel s from lead L and revolutions n, and t
Open →Shafts & Bearings11
Bearing Life (L10)
Compute rated bearing life L10 (10⁶ rev) and L10h (hours). O
Open →Bending Shaft Diameter
Determine minimum shaft diameter under bending moment for so
Open →Torsion Shaft Diameter
Determine minimum shaft diameter under torsion for solid or
Open →Combined Torsion & Bending
With simultaneous bending M and torque T, find diameter by e
Open →Power Transmission Shaft
Design a power shaft by torsional rigidity (twist ≤0.25°/m)
Open →Shaft/Hole Tolerance
Compute upper/lower deviations and limit sizes at a nominal
Open →Bearing Static Load
Determine required basic static load rating C0 from static s
Open →Equivalent Static Load
For ball bearings combine radial Fr and axial Fa with coeffi
Open →Shaft Diameter (Torsion)
Find the minimum solid shaft diameter d for torque T at allo
Open →Shaft Dia (Bending+Torsion)
Per the third strength theory, find shaft diameter d from be
Open →Shaft Critical Speed
Estimate the first critical speed n_cr from static deflectio
Open →Fasteners & Springs11
Bolt Diameter
Find the minimum required thread major diameter for an axial
Open →Thread Engagement Length
Verify thread-flank shear and bearing stress at engagement l
Open →Riveted Joint
Compute rivet shear capacity, plate bearing pressure, plate
Open →Coiled Spring
Compute spring index c, Wahl factor k, torsional stress τ, d
Open →Leaf Spring
Compute bending stress and free-end deflection of a cantilev
Open →Torsion Spring
Compute the bending stress σ, angular deflection θ and torsi
Open →Bolt Preload (Torque)
Back-calculate preload F0 from tightening torque T, nut fact
Open →Bolt Group Max Load
For a circular bolt group under direct shear V and eccentric
Open →Sunk Key Strength
Check shear stress τ and crushing stress σc of a sunk key (T
Open →Spline Torque Capacity
Estimate torque capacity T of an involute spline from tooth-
Open →Interference Fit Press Force
Estimate the maximum press force F from interface pressure p
Open →Power & Motion12
Crank-Slider Mechanism
Compute slider displacement, velocity and acceleration of a
Open →Pulley & Wheel-Axle
Compute mechanical advantage and required effort for wheel-a
Open →Rotational Kinetic Energy
Compute rotational kinetic energy E from moment of inertia I
Open →Translational Kinetic Energy
Compute translational kinetic energy E from mass m and speed
Open →Simple Pendulum Period
Compute the small-amplitude period T of a simple pendulum fr
Open →Spring Potential Energy
Compute spring potential energy U from stiffness k and defle
Open →Centrifugal Force
Compute centrifugal force F from mass m, speed n and radius
Open →Mechanical Work
Compute work W from force F, displacement s and angle θ.
Open →Lever Mechanical Advantage
Compute lever mechanical advantage MA = Le/Ll from effort ar
Open →Open Belt Length
Compute open-belt pitch length from pulley diameters D1/D2 a
Open →Belt Speed
Compute belt speed v (m/s) from pulley diameter D and speed
Open →Flywheel Inertia
Estimate required flywheel inertia I from permitted energy f
Open →Thermal & Fluid14
Hydraulic Cylinder
Compute theoretical thrust, piston velocity and output power
Open →Differential Flowmeter
Compute volumetric flow rate and velocity for orifice/Ventur
Open →Pump / Cylinder Flow
Compute volumetric flow Q from effective area A and fluid ve
Open →Hydraulic Power
Compute hydraulic power P from pressure p and flow Q (with e
Open →Pipe Mean Velocity
Compute mean velocity v from flow Q (m³/h) and pipe dia. d.
Open →Reynolds Number
Compute Reynolds number Re from density ρ, velocity v, chara
Open →Darcy Friction Loss
Compute Darcy friction head loss hf from f, length L, dia. D
Open →Sharp-edged Orifice Flow
Estimate orifice discharge Q from coefficient Cd, dia. D and
Open →Bernoulli Pressure Drop
Compute the dynamic pressure difference Δp (Bernoulli) from
Open →Wall Heat Conduction
Compute conduction heat rate Q via Fourier's law from k, A,
Open →Linear Thermal Expansion
Compute elongation ΔL from CTE α, length L and ΔT.
Open →Convective Heat Transfer
Compute convective heat rate Q from film coefficient h, area
Open →Latent Heat
Compute heat Q absorbed/released in a phase change from mass
Open →Radiative Heat Transfer
Compute radiative heat rate Q from emissivity ε, area A and
Open →Machining15
Cutting Speed & RPM
Compute cutting speed from diameter and RPM, or spindle RPM
Open →Three-Wire Thread
Compute thread pitch diameter d₂ from a three-wire measureme
Open →Base Tangent Length
Compute span number k and base tangent length W for standard
Open →Sheet Metal Drawing
Compute drawing ratio m and first-draw punch force F = π d t
Open →Sheet Metal Blanking
Compute blanking force F = π d t τ and punch face compressiv
Open →Spindle Speed
Compute spindle speed n from cutting speed v (m/min) and too
Open →Feed Rate
Compute table feed rate fm from feed per tooth f, teeth z an
Open →Material Removal Rate
Compute volume removal rate Q (MRR) from depth ap, feed f an
Open →Cutting Force
Compute main cutting force Fc from power P and cutting speed
Open →Tap Drill Size
Compute tap drill diameter D before tapping (≈ d − P) from n
Open →Thread Height
Compute tooth height H and minor dia. d1 of a 60° metric thr
Open →Sheet Bend Allowance
Compute flat length L from legs A/B, bend angle α, inner rad
Open →Punching Force
Compute punching force F from shear perimeter P, thickness t
Open →Circumferential Speed
Compute circumferential speed v (m/s) from dia. D (mm) and s
Open →Drilling Time
Estimate single-hole drilling time t from depth L, approach
Open →Electrical Engineering 23
Circuit & Energy11
Ohm's Law
Given any two of voltage U, current I, resistance R, solve t
Open →Current Intensity
Compute average current from I = Q/t, with reverse solutions
Open →Resistance Formula
Compute conductor resistance R and conductance G=1/R from re
Open →Joule's Law
Compute heat Q = I² R t from current, resistance and time; r
Open →Equivalent Resistance
Compute equivalent resistance of resistors in series or para
Open →Electric Work
Compute electrical energy from W = U I t and convert to joul
Open →Capacitor Energy
Compute energy E stored in a capacitor from C (µF) and volta
Open →Inductor Energy
Compute energy E stored in an inductor from L (mH) and curre
Open →Cable Voltage Drop
Estimate single-phase cable voltage drop ΔV from current I,
Open →Battery Runtime
Estimate battery runtime t from capacity (mAh) and load curr
Open →Wheatstone Bridge
Compute unknown resistance Rx at balance from known arms R1/
Open →AC, Motors & EM Fields12
Motor Rated Torque
Based on T = 9550 P/n: torque from power & speed, power from
Open →RC Time Constant
Compute the time constant τ of a first-order RC circuit from
Open →RL Time Constant
Compute the time constant τ of a first-order RL circuit from
Open →RL Series Impedance
Compute RL series impedance |Z| and reactance XL from R, L (
Open →RC Series Impedance
Compute RC series impedance |Z| and reactance XC from R, C (
Open →Three-phase Power
Compute three-phase active power P from line voltage V, line
Open →Three-phase Current
Compute line current I from active power P (kW), line voltag
Open →Transformer Turns Ratio
Compute turns ratio and secondary current I2 from primary/se
Open →Power Factor Angle
Compute power-factor angle φ and reactive power Q from cosφ
Open →LC Resonance Frequency
Compute resonant frequency f0 of an LC tank from L (mH) and
Open →Point-charge Electric Field
Compute electric field E of a point charge Q (µC) at distanc
Open →Solenoid Magnetic Field
Compute central magnetic flux density B of a long solenoid f
Open →Civil Engineering 9
Civil Engineering9
Force Composition
Compute resultant magnitude and direction of two concurrent
Open →Moment Calculator
Compute force moment M = F·l·sinθ or couple moment M = F·d,
Open →Force Equilibrium
For two known forces P, Q at an angle, compute the resultant
Open →Rankine Active Earth Pressure
Compute Rankine active earth-pressure coefficient Ka and tot
Open →Overturning Safety Factor
Compute overturning safety factor FS from resisting and over
Open →SS Beam Point Load
Compute reactions R and mid-span max moment Mmax of a simply
Open →Fixed-end Beam (UDL)
Compute fixed-end moment M and reaction R of a beam fixed at
Open →Column Axial Stress
Compute axial compressive stress σ of a column from axial lo
Open →Single Pile Capacity
Estimate vertical capacity Q of a single pile from end beari
Open →Unit Conversion 61
Basic Physical Quantities11
Length Converter
Instantly convert Length between SI and common engineering u
Open →Mass Converter
Instantly convert Mass between SI and common engineering uni
Open →Area Converter
Instantly convert Area between SI and common engineering uni
Open →Volume Converter
Instantly convert Volume between SI and common engineering u
Open →Luminous Intensity Converter
Instantly convert Luminous Intensity between SI and common e
Open →Illuminance Converter
Instantly convert Illuminance between SI and common engineer
Open →Luminance Converter
Instantly convert Luminance between SI and common engineerin
Open →Radioactivity Converter
Instantly convert Radioactivity between SI and common engine
Open →Radiation Dose Converter
Instantly convert Radiation Dose between SI and common engin
Open →Amount of Substance Converter
Instantly convert Amount of Substance between SI and common
Open →Wave Number Converter
Instantly convert Wave Number between SI and common engineer
Open →Mechanics & Strength6
Force Converter
Instantly convert Force between SI and common engineering un
Open →Pressure Converter
Instantly convert Pressure between SI and common engineering
Open →Stress Converter
Instantly convert Stress between SI and common engineering u
Open →Torque Converter
Instantly convert Torque between SI and common engineering u
Open →Moment of Inertia Converter
Instantly convert Moment of Inertia between SI and common en
Open →Section Modulus Converter
Instantly convert Section Modulus between SI and common engi
Open →Dynamics & Motion10
Power Converter
Instantly convert Power between SI and common engineering un
Open →Speed Converter
Instantly convert Speed between SI and common engineering un
Open →Acceleration Converter
Instantly convert Acceleration between SI and common enginee
Open →Volumetric Flow Rate Converter
Instantly convert Volumetric Flow Rate between SI and common
Open →Angular Velocity Converter
Instantly convert Angular Velocity between SI and common eng
Open →Angle Converter
Instantly convert Angle between SI and common engineering un
Open →Angular Acceleration Converter
Instantly convert Angular Acceleration between SI and common
Open →Momentum / Impulse Converter
Instantly convert Momentum / Impulse between SI and common e
Open →Mass Moment of Inertia Converter
Instantly convert Mass Moment of Inertia between SI and comm
Open →Jerk Converter
Instantly convert Jerk between SI and common engineering uni
Open →Energy & Refrigeration11
Energy Converter
Instantly convert Energy between SI and common engineering u
Open →Work Converter
Instantly convert Work between SI and common engineering uni
Open →Heat Converter
Instantly convert Heat between SI and common engineering uni
Open →Refrigeration Converter
Instantly convert Refrigeration between SI and common engine
Open →Temperature Converter
Instantly convert Temperature between SI and common engineer
Open →Specific Energy Converter
Instantly convert Specific Energy between SI and common engi
Open →Specific Heat Capacity Converter
Instantly convert Specific Heat Capacity between SI and comm
Open →Thermal Conductivity Converter
Instantly convert Thermal Conductivity between SI and common
Open →Heat Flux Converter
Instantly convert Heat Flux between SI and common engineerin
Open →Heat Transfer Coefficient Converter
Instantly convert Heat Transfer Coefficient between SI and c
Open →Thermal Expansion Coeff. Converter
Instantly convert Thermal Expansion Coeff. between SI and co
Open →Fluid & Chemical8
Mass Flow Rate Converter
Instantly convert Mass Flow Rate between SI and common engin
Open →Density Converter
Instantly convert Density between SI and common engineering
Open →Dynamic Viscosity Converter
Instantly convert Dynamic Viscosity between SI and common en
Open →Kinematic Viscosity Converter
Instantly convert Kinematic Viscosity between SI and common
Open →Concentration Converter
Instantly convert Concentration between SI and common engine
Open →Specific Volume Converter
Instantly convert Specific Volume between SI and common engi
Open →Molar Concentration Converter
Instantly convert Molar Concentration between SI and common
Open →Surface Tension Converter
Instantly convert Surface Tension between SI and common engi
Open →Time & Computer4
Time Converter
Instantly convert Time between SI and common engineering uni
Open →Frequency Converter
Instantly convert Frequency between SI and common engineerin
Open →Data Storage Converter
Instantly convert Data Storage between SI and common enginee
Open →Data Rate Converter
Instantly convert Data Rate between SI and common engineerin
Open →Electrical Engineering11
Magnetic Flux Converter
Instantly convert Magnetic Flux between SI and common engine
Open →Magnetic Flux Density Converter
Instantly convert Magnetic Flux Density between SI and commo
Open →Magnetomotive Force Converter
Instantly convert Magnetomotive Force between SI and common
Open →Electric Charge Converter
Instantly convert Electric Charge between SI and common engi
Open →Capacitance Converter
Instantly convert Capacitance between SI and common engineer
Open →Inductance Converter
Instantly convert Inductance between SI and common engineeri
Open →Electric Potential Converter
Instantly convert Electric Potential between SI and common e
Open →Resistance Converter
Instantly convert Resistance between SI and common engineeri
Open →Conductance Converter
Instantly convert Conductance between SI and common engineer
Open →Permeability Converter
Instantly convert Permeability between SI and common enginee
Open →Permittivity Converter
Instantly convert Permittivity between SI and common enginee
Open →