Math & Numbers
Compute the Darcy-Weisbach major (friction) pressure drop in a straight pipe: ΔP = f·(L/D)·(ρ·v²/2) Pa and head loss h_f = f·(L/D)·v²/(2g) m. The user supplies the Darcy friction factor f (not the Fanning factor). Length in m/km/ft, diameter in m/cm/mm/inch, density in kg/m³/g/cm³/lb/ft³ — all normalised to SI internally. Returns ΔP in Pa, kPa and bar, and head loss in m and ft. Gravity defaults to 9.81 m/s² and may be overridden.
pipe-pressure-drop-darcyMath & Numbers
Compute the available Net Positive Suction Head (NPSH_a) of a pump and compare it against the required NPSH (NPSH_r) from the pump curve. Head-balance form: NPSH_a = (p_surface_abs - p_vapor) / (ρ·g) + H_static - h_friction. Surface and vapor pressures are absolute; H_static is positive for flooded suction, negative for suction lift. Returns margin (NPSH_a - NPSH_r), ratio (NPSH_a/NPSH_r) and a classification: safe, marginal (margin < 0.5 m), or cavitation likely. If NPSH_r = 0, only NPSH_a is reported. Pressure in Pa/kPa/bar/atm/psi, length in m/ft, density in kg/m³/g/cm³/lb/ft³.
pump-npsh-calculatorMedia
Store PNG pixels as true 16-bit-per-channel grayscale, 48-bit RGB, or 64-bit RGBA PNG.
png-to-16bit-pngMath & Numbers
Size the shunt capacitor needed to raise the power factor: C = P·(tanφ₁ − tanφ₂)/(2π·f·U²). Returns compensated reactive power Qc, capacitive reactance Xc, capacitor current Ic, and the required capacitance in F/μF.
power-factor-correctionMath & Numbers
Calculate the overall efficiency of a multi-stage transmission. η_total = η₁·η₂·…·ηₙ. Enter one stage efficiency per line (decimal, e.g. 0.98). Optionally add an input power to get the total loss and per-stage output power.
power-transmission-efficiencyFinance
Discount a future lump sum or an annuity back to today's value (PV). Supports lump-sum and annuity cash flows, multiple compounding frequencies, a present-value decay curve, and a per-period breakdown. PV = FV / (1+r)^n for a lump sum.
present-value-calculatorHealth
Estimate your daily protein target in grams from body weight and activity level. Coefficients (g per kg bodyweight) follow the ISSN 2017 position stand and the Morton et al. 2018 meta-analysis.
protein-intake-calculatorMath & Numbers
Convert between pH, [H+], pOH and [OH-], or compute pH from a strong acid/base concentration, including dilution.
ph-calculatorEducation
Compute 2-3 gene Mendelian crosses with a full Punnett square and forked-line branch diagram. Supports complete, incomplete and codominance inheritance.
punnett-trihybrid-crossMath & Numbers
Solve pressure, force, or area from P=F/A, and convert between Pa, kPa, MPa, bar, atm, psi, Torr, inHg, kgf/cm²
pressure-conversionMath & Numbers
Compute gravitational potential energy, mass, or height from the other two, with impact velocity
potential-energy-calculatorMath & Numbers
Compute range, max height, flight time, and the full trajectory of a projectile given speed, angle, and optional initial height
projectile-motion-calculator