Science & Engineering

Build Punnett squares for monohybrid and dihybrid crosses (Aa × Aa, AaBb × AaBb) and get genotype and phenotype ratios and probabilities.

Reverse-complement, complement, transcribe and translate DNA or RNA sequences, and get the length, GC content and base counts.

Calculate cell concentration and viability from hemocytometer counts: cells per mL, total cells, and the volume needed to seed a target number of cells.

Calculate the molar mass (molecular weight) of any chemical formula — including brackets and hydrates like CuSO4·5H2O — with the mass percentage of each element.

Balance chemical equations automatically — combustion, redox and precipitation reactions — with the smallest whole-number coefficients.

Searchable periodic table of all 118 elements with atomic number, symbol, name, standard atomic weight and element category.

Calculate molarity, moles, mass or volume of a solution, or solve a dilution with C₁V₁ = C₂V₂.

Calculate pH, pOH, [H⁺] and [OH⁻] from any one of them — or the pH of a weak acid from its concentration and Ka.

Solve the ideal gas law for pressure, volume, moles or temperature — with unit choices for kPa, atm, bar, litres and °C, K or °F.

Calculate how much of a radioactive isotope or drug remains after a given time — or the half-life or time from the amounts — with exponential decay.

Solve density = mass ÷ volume for any of the three, with a list of common material densities for reference.

Find the 'feels like' temperature: heat index from temperature and humidity, or wind chill from temperature and wind speed, using the US National Weather Service formulas.

Calculate the dew point from air temperature and relative humidity — or relative humidity from temperature and dew point — with a comfort rating.

Find sunrise, sunset, solar noon and day length for any location and date from its latitude and longitude.

Find the moon phase, illumination and moon age for any date — plus the dates of the next new moon and full moon.

Find the right air conditioner size in BTU for a room using the ENERGY STAR chart, with adjustments for sun, occupants and kitchens — plus a heating BTU estimate by climate.

Estimate your yearly CO₂ emissions from driving, home electricity, natural gas and flights — with editable emission factors based on US EPA data.

Estimate how much rainwater you can collect from a roof in a storm, a month or a year — in gallons or litres — and the tank size you'd need.

Enter any two of voltage, current, resistance and power to calculate the other two with Ohm's law and the power formulas.

Decode 4, 5 and 6-band resistor color codes into resistance, tolerance and temperature coefficient — or find the bands for a value.

Calculate voltage drop over a copper or aluminum cable run by AWG size, current and length — and find the smallest wire gauge that keeps the drop under 3%.

Convert between watts, amps and volts for DC, single-phase AC and three-phase circuits, including power factor.

Estimate how long a battery will run a device from its capacity (mAh or Wh), the device's current or power draw, and usable capacity.

Find the current-limiting resistor for LEDs (single or in series) with the nearest standard E12 value, or calculate a voltage divider's output.

Calculate capacitive and inductive reactance at a frequency, the LC resonant frequency, and total capacitance or inductance in series and parallel.

Estimate how many solar panels and what system size (kW) you need to cover your electricity use, the yearly savings and the payback period.

Work out the generator size you need from the appliances you want to run — running watts plus the largest motor's starting surge.

Solve constant-acceleration motion problems: enter any three of initial velocity, final velocity, acceleration, time and displacement to get the other two.

Calculate force from mass and acceleration (F = ma), weight on Earth and other planets, kinetic energy and gravitational potential energy.

Calculate the range, maximum height and flight time of a projectile from its launch speed, angle and launch height (no air resistance).

Calculate torque from force and lever arm, and a gear train's ratio, output speed and output torque from the tooth counts.

Calculate flow rate from pipe diameter and velocity (or velocity from flow), in L/min, GPM and m³/h, plus the Reynolds number for water.

Calculate how far sound or light travels in a given time — including how far away lightning is from the delay before thunder — with sound speed adjusted for air temperature.

Convert between frequency and wavelength for radio, light and sound waves — plus photon energy for electromagnetic waves.

Add sound levels in decibels, find the difference between two levels as a ratio, and convert between dB and power or amplitude ratios.

Compare earthquakes by magnitude: the energy released, the TNT equivalent and how many times stronger one quake is than another.

Convert real-world sizes to model sizes and back for any scale — 1:24, 1:43, 1:87 (HO), 1:160 (N) and more — in mm, cm or inches.

Estimate the cost of a 3D print from filament used, filament price, print time, printer power and machine wear — plus a selling price with markup.

Calculate maximum deflection, bending moment, stress and reactions for simply supported and cantilever beams with point or uniform loads — rectangular sections in wood, steel or aluminum.