Solve motor and shaft performance with flexible engineering inputs. Check results before equipment sizing decisions. Export clear reports for documentation, maintenance planning, and audits.
Use any two rotating-machine quantities plus speed information to solve the missing engineering value with automatic unit conversion.
| Case | Torque (N·m) | Speed (RPM) | Power (kW) | Efficiency (%) | Service factor | Design power (kW) |
|---|---|---|---|---|---|---|
| Pump Drive | 220 | 1450 | 33.41 | 91 | 1.15 | 38.42 |
| Conveyor Reducer | 950 | 180 | 17.91 | 88 | 1.30 | 23.28 |
| Fan Motor | 120 | 2900 | 36.44 | 93 | 1.10 | 40.08 |
These equations help size motors, shafts, reducers, couplings, and rotating equipment under expected running conditions and conservative design allowances.
Torque power calculations connect rotational force with motion rate. Engineers compare shaft torque, operating speed, and transmitted power to verify that motors, reducers, and couplings remain inside rating limits. Because angular velocity rises directly with RPM, even a moderate speed increase can raise power demand quickly. This calculator solves the missing variable and returns outputs for review.
Field data rarely arrives in one unit system. Maintenance logs may show pound-feet, vendor sheets may show horsepower, and drawings may show metric values. Converting everything to N·m, watts, and rad/s first reduces interpretation errors and creates a common engineering baseline. The tool then reports several output units, helping teams compare catalogs, test readings, and supplier documents without repeated manual conversion.
Output power does not equal input power when mechanical or electrical losses are present. Bearings, seals, belts, gears, and windings consume part of the supplied energy before useful shaft work appears. If efficiency falls from 95 percent to 88 percent, required input power increases noticeably for the same delivered load. Including efficiency helps estimate upstream demand that feeders, drives, and motors must carry.
A design that works only at nominal load may still fail in operation. Starting torque, shock loading, fluctuating material density, and duty changes usually require additional margin. Service factor converts that uncertainty into a more conservative design power figure. This is useful for conveyors, mixers, pumps, and fans, where transient loads may exceed steady-state calculations and undersized parts can accelerate wear, slippage, or overheating.
The shortcut formula, power in kilowatts equals torque multiplied by RPM divided by 9550, is valuable because it compresses angular velocity conversion into one familiar expression. Accuracy still depends on correct units and sensible validation. Entering torque in lb-ft while assuming N·m can distort power estimates enough to affect decisions. Good calculators therefore combine convenience, visible formulas, and exportable records.
Used correctly, torque power analysis supports equipment sizing, maintenance planning, and troubleshooting. It helps explain motor overheating, reducer trips, and shaft loading limits during process changes. With exports, plotted trends, and consistent formulas, teams can document assumptions, compare scenarios, and defend decisions with numbers instead of rough approximations.
Power equals torque multiplied by angular velocity. If speed is entered in RPM, the calculator also applies the engineering shortcut: power in kilowatts equals torque in N·m times RPM divided by 9550.
Service factor multiplies output power to estimate a more conservative design requirement. It helps account for shock loads, start-stop duty, variable material density, and other operating conditions that exceed nominal running values.
Efficiency estimates the extra input power needed to deliver the required shaft output. Lower efficiency means the upstream motor or drive must supply more energy for the same useful mechanical work.
The calculator accepts torque in N·m, lb-ft, lb-in, and kgf·m. Power can be entered in W, kW, MW, hp, or PS, with speed in RPM or rad/s.
Solve for speed when torque and power are known from design targets, test data, or catalog limits. This helps verify whether the intended operating point is realistic for the selected machine.
The graph plots a constant-torque operating curve across a speed range and marks the current operating point. It makes it easier to visualize how power demand rises as rotational speed increases.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.