An engineering reference, built to be checked.
Unit conversions, calculators and substance solution properties — every page shows the formula and cites its sources, written for engineers who verify their own numbers.
No animations. No pop-ups. No nonsense.
- Calculators
- 91
- Guides
- 77
- Substance hubs
- 59
- Conversions
- 5,072
Calculators with worked examples
Each one shows its formula, assumptions, limitations and a worked example, so the result can be checked by hand.
Pipe Velocity / Flow / Diameter Calculator
Calculate pipe velocity, volumetric flow, or internal diameter from the other two values.
Pumps & Rotating EquipmentPump Hydraulic Power Calculator
Calculate hydraulic power and shaft power from flow, head, density, gravity, and pump efficiency.
Heat TransferHeat Duty Calculator
Calculate sensible heat duty from mass flow rate, specific heat capacity, and temperature change. Continuous and batch modes.
Process DesignResidence Time Calculator
Calculate hydraulic residence time, vessel volume, or volumetric flow rate from the other two values.
Process DesignDilution Calculator
Calculate dilution using C₁V₁ = C₂V₂. Solve for any one of concentration or volume when the other three are known.
Process DesignSlurry Density Calculator
Calculate slurry density and percent solids from liquid density, solids density, and the solids loading — entered as mass percent, volume percent, or g/L of slurry. Includes a target-density lab-prep mode that returns the mixture proportions for a desired slurry density.
Process DesignSlurry Mass Balance Calculator
From slurry volumetric flow, slurry density, and percent solids by mass, calculate slurry/solids/liquid mass flows, component volumetric flows, and percent solids by volume.
Process DesignPercent Solids Mass ↔ Volume Calculator
Convert between percent solids by mass (Cw) and percent solids by volume (Cv) using the liquid density and the solids density. Returns the slurry density, slurry SG, all four phase fractions, and the liquid:solids ratios.
Fluid MechanicsFriction Factor Calculator
Calculate the Darcy friction factor from Reynolds number and relative roughness using the laminar formula or Swamee-Jain explicit turbulent approximation.
PipingPipe Pressure Drop Calculator
Estimate the pressure drop and head loss in a straight circular pipe from flow rate, pipe size, and fluid properties — Darcy-Weisbach friction with an optional minor-loss (K) and elevation allowance. Friction factor is computed for you.
Heat TransferHeat Exchanger Area Calculator
Estimate preliminary heat-transfer area from duty, U-value, LMTD, correction factor, and design margin.
Pumps & Rotating EquipmentNPSH Available Calculator
Estimate net positive suction head available (NPSHa) for preliminary suction-side pump checks, using head terms or absolute-pressure terms.
HydrometallurgyCCD Wash Water Calculator
Estimate the wash-water flow required in a counter-current decantation (CCD) circuit from the dry solids rate, thickener underflow solids concentration, and a target wash ratio.
HydrometallurgyLeach Reagent Consumption Calculator
Estimate reagent consumption rate and daily consumption from dry solids throughput and reagent dosage, with an optional daily reagent cost.
PsychrometricsWet-Bulb Temperature Calculator
Calculate the wet-bulb temperature of moist air from dry-bulb temperature, relative humidity and pressure, with the full psychrometric property set.
PsychrometricsDew Point Calculator
Calculate the dew point of moist air from dry-bulb temperature, relative humidity and pressure, with the full psychrometric property set.
PsychrometricsHumidity Ratio & Enthalpy Calculator
Calculate the humidity ratio (g/kg dry air) and specific enthalpy (kJ/kg dry air) of moist air from dry-bulb temperature, relative humidity and pressure, with the full psychrometric property set.
RefrigerationSuperheat Calculator
Calculate refrigerant superheat from gauge pressure (psig) and suction-line temperature (°F) for nine refrigerants, against the dew line for zeotropic blends.
RefrigerationSubcooling Calculator
Calculate refrigerant subcooling from gauge pressure (psig) and liquid-line temperature (°F) for nine refrigerants, against the bubble line for zeotropic blends.
Heat-transfer fluidsFreeze-Protection Concentration Selector
Find the minimum glycol, alcohol or brine concentration (wt%) whose committed freeze point meets a target temperature, with the bracketing freeze-table rows and the viscosity/heat-capacity trade-off.
HydrometallurgyKiln Residence Time Calculator
Estimate rotary-kiln solids residence time from length, internal diameter, rotation speed and slope using the Sullivan, Maier & Ralston (1927) relation t = 0.19·L/(N·D·s), with three-mode slope entry (m/m, %, degrees).
HydrometallurgyLeach Tank Sizing Calculator
Size leach/agitation tanks for a stated residence time from slurry flow (direct Q or a solids basis), residence time, tanks in series and live-volume fraction, with per-tank volume and optional D and H.
Solution properties, computed and cited
Density, viscosity, heat capacity and freezing points of aqueous process chemicals against concentration and temperature — computed from published correlations and validated against cited references.
Sulfuric acid
H2SO4density · viscosity · heat capacity · specific gravity · Baumé
Hydrochloric acid
HCldensity · viscosity · heat capacity · specific gravity · Baumé
Sodium hydroxide
NaOHdensity · viscosity · heat capacity · specific gravity
Sodium chloride
NaCldensity · viscosity · heat capacity · specific gravity
Calcium chloride
CaCl2density · viscosity · heat capacity · specific gravity
Copper(II) sulfate
CuSO4density · viscosity · heat capacity · specific gravity
Ethylene glycol
C2H6O2density · viscosity · heat capacity · specific gravity
Propylene glycol
C3H8O2density · viscosity · heat capacity · specific gravity
Methanol
CH3OHdensity · viscosity · heat capacity · specific gravity
Concepts and reference data
Concept guides explain the engineering behind the calculations; reference pages collect the design data — U-values, K-values, fouling factors and more.
- What Is Pump Head?Pump head is energy per unit weight of fluid, expressed as an equivalent height of liquid column. Learn why it matters for pump selection and how it relates to pressure.
- Pressure vs Head ExplainedPressure is force per area; head is equivalent fluid column height. Learn how density connects them and when to use each.
- Mass Flow vs Volumetric FlowVolumetric flow measures volume per time; mass flow measures mass per time. Learn the density relationship and when each matters.
- Heat Duty ExplainedHeat duty is the rate of heat transfer needed to change a fluid temperature. Learn the sensible heat formula, required inputs, and common mistakes.
- Heat Exchanger Typical U-Values ReferenceTypical overall heat transfer coefficient (U-value) ranges for common heat exchanger types and fluid combinations. Use for preliminary sizing estimates — not final design values.
- Pipe Fitting K-Values ReferenceReference-style typical resistance coefficient (K) values for common fittings and valves used with minor-loss calculations. Preliminary values only — geometry, size, Reynolds number, and valve opening all matter. Pairs with the Minor Loss calculator.
- Typical Slurry Density Ranges ReferenceBroad, preliminary typical slurry density and percent-solids ranges by ore type and processing stage — iron ore, gold, copper, alumina, lithium, coal, and tailings/thickener/transport context. Educational ranges only, not site-specific design values.
- Tank Freeboard / Working Volume ReferenceA concise reference for the volumes used in preliminary tank calculations — total geometric, working, and operating volume; freeboard, ullage, heel/dead volume, surge/buffer volume, and fill fraction — with the basic geometric formulas, why tanks are not operated full, and the common mistakes. Preliminary use only; not a mechanical-design standard.
Conversions by domain
Process Conditions
3 categoriesState variables that define a process stream.
Pressure · Vacuum · Temperature
Flow & Transport
4 categoriesRates and speeds for fluids and bulk material movement.
Volumetric Flow Rate · Mass Flow Rate · Volumetric Flux · Velocity
Materials & Properties
6 categoriesPhysical properties of fluids, solids and mixtures.
Density and Mass · Viscosity · Specific Properties · Concentration · +2 more
Mechanical & Dimensional
5 categoriesForces, motion and geometry for mechanical design.
Force and Torque · Acceleration · Length and Area · Volume · +1 more
Energy & Heat
5 categoriesPower, energy and heat-transfer engineering.
Power and Energy · Heat Transfer · Thermal Resistance · Thermal Capacity · +1 more
Measurement & Instrumentation
6 categoriesElectrical, optical and radiological measurement quantities.
Electrical · Photometry · Radiation Dose · Frequency · +2 more
Three things every page guarantees.
The same standard applied across every category — from pressure and flow to radiation and surface tension.
Deterministic
Every conversion factor is hard-coded from SI definitions. No floating-point drift between sessions.
Auditable
Every page shows the formula and a worked example. You can verify the math in seconds.
Fast
Static pages, no client-side bundle besides the converter itself. Loads on a 3G connection.