Science & Engineering
31 toolsChemistry, physics, and electronics calculators - molar mass, ideal gas law, projectile motion, half-life, LED resistors, voltage dividers, and more. All run in your browser.
Calculators for chemistry, physics, and electronics coursework and bench work: molar mass, gas laws, projectile motion, and a practical electronics set covering LED resistors, voltage dividers, wire gauge, and timer circuits.
Reference tools like the periodic table and physics constants live here too, so you can look up a value and plug it in without switching sites.
Most popular
Chemistry
- Molar Mass Enter a chemical formula (e.g. H₂O, NaCl, C₆H₁₂O₆) and instantly calculate molar mass with a per-element breakdown. Supports parentheses and nested groups.
- Molarity Calculate solution molarity (moles per liter), dilute solutions using C₁V₁=C₂V₂, and convert between grams, moles, and liters. All offline.
- Ideal Gas Law Solve PV=nRT for any unknown variable. Supports atm, Pa, kPa, bar for pressure; L, mL for volume; K and °C for temperature. Shows step-by-step working.
- Half-Life Calculate remaining quantity, elapsed time, or half-life for radioactive decay using N(t)=N₀×(½)^(t/t½). Supports any initial quantity and time unit.
- pH Calculator Convert between pH, hydrogen ion concentration [H], and pOH. Determine whether a solution is acidic, neutral, or basic.
- Periodic Table Browse all 118 elements with atomic number, symbol, mass, category, period, and group. Search by name, symbol, or number.
Physics & Mechanics
- Projectile Motion Calculate projectile range, maximum height, time of flight, and velocity components from initial speed and launch angle. Supports m/s and ft/s.
- Free Fall Calculate free-fall distance, velocity, or time using h=½gt² and v=gt. Supports metric (m/s²) and imperial (ft/s²). Ignores air resistance.
- Kinetic Energy Calculate kinetic energy (KE = 1/2mv^2) and gravitational potential energy (PE = mgh). Solve for any of mass, velocity, or height.
- Pendulum Calculator Calculate the period (T = 2pisqrt(L/g)), frequency, and length of a simple pendulum. Enter any two values to solve for the third. Supports custom gravitational acceleration.
- Hooke's Law Solve Hooke's Law F = kx for force, spring constant, or extension. Also calculates elastic potential energy stored in the spring (U = 1/2kx^2).
- Density Calculate density, mass, or volume using D = m/V. Supports metric and imperial units. Shows the triangle relationship and common material densities for reference.
- Specific Heat Solve the specific heat equation Q = m x c x T for any of the four variables: heat energy (Q), mass (m), specific heat capacity (c), or temperature change (T). Includes a table of common materials.
- Reynolds Number Calculate the Reynolds number (Re = vL/) for any fluid and pipe geometry. Instantly determine whether flow is laminar, transitional, or turbulent.
- Physics Constants Look up 20+ fundamental physics constants including speed of light, Planck constant, gravitational constant, and more.
Waves, Light & Sound
- Wavelength & Frequency Convert between wavelength and frequency for light, radio waves, and sound. Uses c=λf for EM waves and v=λf for sound with a customizable wave speed.
- Doppler Calculator Calculate the observed frequency of a moving sound source using the Doppler effect formula. Enter source frequency, velocities, and wave speed to compute the perceived frequency and pitch shift in semitones.
- Snell's Law Solve Snell's Law nsin(theta) = nsin(theta) for the refracted angle or refractive index. Automatically detects total internal reflection and shows the critical angle.
- Lens Calculator Solve the thin lens equation for focal length, object distance, or image distance. Computes magnification and tells you whether the image is real or virtual, upright or inverted.
- Decibel Calculator Convert between decibels and voltage or power ratios. Calculate sound pressure level (dB SPL) from pressure in Pascals. Convert dB to amplitude ratios and back.
Electronics
- LED Resistor Calculate the correct series resistor for your LED circuit. Enter supply voltage, forward voltage, and forward current; get resistance in ohms and nearest E12 value.
- Voltage Divider Solve the voltage divider formula V_out = V_in × R2/(R1+R2) for any unknown. Shows current draw and supports standard E12/E24 resistor series lookup.
- Wire Gauge (AWG) Look up AWG wire gauge properties: diameter (mm/in), cross-section area, resistance per 100 ft/m, and maximum current capacity for chassis and in-wall wiring.
- Battery Life Estimate battery runtime from capacity (mAh) and current draw (mA). Add an efficiency factor (%) and optionally include self-discharge rate for accurate projections.
- Capacitor Code Decode 3-digit ceramic capacitor codes (like 104 = 100 nF) to picofarads, nanofarads, and microfarads. Also convert a capacitance value back to its 3-digit code.
- NE555 Calculator Calculate NE555 timer frequency, period, duty cycle, and pulse width for both astable (oscillator) and monostable (one-shot) configurations. Enter R1, R2, and capacitor values.
- Op-Amp Calculator Calculate op-amp gain for inverting, non-inverting, and difference amplifier configurations. Enter Rf and Rin to get the gain, or supply input voltage to compute the output.
- Logic Gates Simulate AND, OR, NOT, NAND, NOR, XOR, XNOR, and BUFFER logic gates interactively.
Home & Environment
- BTU Calculator Calculate the BTU cooling capacity needed for a room based on dimensions, insulation, sun exposure, and occupancy.
- Pool Calculator Calculate swimming pool volume in gallons or litres and the chlorine dose needed to reach a target ppm for rectangular, oval, or round pools.
- Carbon Footprint Estimate your personal annual CO₂e emissions from transport, home energy, diet, and shopping. See a breakdown by category and get personalised reduction tips.
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