Engineering calculators

Electrical, mechanical, structural and computing formulas.

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Bandwidth Calculator
Bandwidth needed for users and streams.
Battery Runtime Calculator
Estimated runtime from battery capacity and load current.
Beam Load Calculator
Bending moment and deflection for a beam.
Duct Size Calculator
Duct diameter for a target airflow.
Gear Ratio Calculator
Ratio, output speed and torque.
Generator Sizing Calculator
Minimum generator size for a set of household or site loads.
HVAC Load Calculator
Cooling load in BTU and tons.
LED Resistor Calculator
Series resistor for any LED.
Password Entropy Calculator
Entropy bits and crack time.
Power Factor Correction Calculator
Capacitor kVAr needed to fix power factor.
RAID Storage Calculator
Usable storage capacity for common RAID levels.
RC Time Constant Calculator
Charge time and cutoff frequency.
Resistor Series/Parallel Calculator
Total resistance for two resistors in series or parallel.
Resistor Value Calculator
Resistance from band values and tolerance.
RPM to Speed Calculator
Vehicle speed from engine RPM.
Screen PPI Calculator
Pixel density and viewing distance.
Subnet Calculator
Hosts, mask and ranges for a CIDR block.
Three Phase Power Calculator
kW, kVA and current for 3-phase loads.
Transformer Turns Ratio Calculator
Voltage, current and turns for a transformer.
Voltage Divider Calculator
Output voltage, current and power for a two-resistor divider.
Wire Gauge Ampacity Calculator
Safe current rating for common copper wire gauges.
Wire Voltage Drop Calculator
Voltage drop over a wire run by length and gauge.