Example engineering calculations
Worked, unit-aware calculation worksheets across structural, mechanical, electrical and more. Open any example into your own workspace to edit and reuse. New to Calculeaf? Start with your first worksheet or the examples guide.
515 examples
Percentage Voltage Drop Check on a Feeder
Voltage drop expressed as a percentage of nominal voltage for a quick feeder compliance check.
Solar PV Array Panel Count Sizing
Number of solar panels needed to meet a daily energy target given peak sun hours and system efficiency.
Battery Bank Capacity for Backup Power
Battery bank capacity in amp-hours needed to power a backup load for a target duration.
Battery Charge Time from Charger Current
Time needed to recharge a battery from its amp-hour capacity and the charger’s current output.
Wind Turbine Power Output
Mechanical power a wind turbine extracts from the wind given rotor size, wind speed, and power coefficient.
Non-Inverting Op-Amp Gain
Voltage gain of a non-inverting operational amplifier stage from its feedback resistor ratio.
RC Low-Pass Filter Cutoff Frequency
Cutoff (-3 dB) frequency of a simple resistor-capacitor low-pass filter.
LED Series Current-Limiting Resistor
Series resistor value needed to limit current through an LED to its safe rated value.
Total Harmonic Distortion (Two Harmonics, Simplified)
Total harmonic distortion of a waveform from its fundamental and two harmonic voltage components.
Power Inverter Efficiency
Conversion efficiency of a power inverter from its output and input power.
Conductor Cross-Section from Allowable Voltage Drop
Minimum conductor cross-sectional area needed to keep voltage drop within an allowable limit.
Distillation Column Reflux Ratio
The ratio of liquid returned to the top of a distillation column versus product drawn off, the main knob operators turn to trade separation quality against energy cost.
Heat Released by Fuel Combustion
The total chemical energy released when a known mass of fuel is burned, found from its higher heating value.
CSTR Reactor Residence Time
The average time a fluid element spends inside a continuously stirred tank reactor, the key variable that controls conversion.
PFR Conversion for a First-Order Reaction
The fractional conversion achieved in a plug-flow reactor running a first-order reaction, from the rate constant and residence time.
Mass Transfer NTU from a Volumetric Coefficient
The number of transfer units (NTU) for a mass-transfer contactor, built from a lumped volumetric mass-transfer coefficient and the contact time.
Minimum Fluidization Velocity (Simplified Force Balance)
The superficial gas velocity at which drag on a bed of particles just balances their submerged weight, marking the onset of fluidization.
Evaporator Steam Economy
The ratio of water vapor evaporated to steam consumed in a process evaporator, a key efficiency metric for concentration plants.
Absorption Column Packing Height (HTU–NTU)
The required packing height for a gas absorption column, found from the height of a transfer unit times the number of transfer units needed.
Dilution to a Target Concentration
The volume of solvent needed to dilute a stock solution down to a target concentration, from the conservation of solute mass.
Vapor Pressure Estimate (Antoine Equation)
An estimate of a liquid's vapor pressure at a given temperature using the empirical three-constant Antoine equation.
Rankine Cycle Thermal Efficiency (Simplified)
A first-law estimate of Rankine (steam power) cycle efficiency directly from the heat added and heat rejected per unit mass of working fluid.
Brayton Cycle Thermal Efficiency
The ideal thermal efficiency of a gas turbine (Brayton) cycle from its pressure ratio and the working gas's specific heat ratio.
Vapor-Compression Refrigeration COP
The coefficient of performance of a vapor-compression refrigeration or air-conditioning cycle, the ratio of cooling delivered to compressor work spent.