Science & engineering
Physics, chemistry, electronics and energy calculators for coursework and quick engineering checks — an order of magnitude confirmed before a design, a bill, or an answer depends on it. Units are stated on every field, since mixing systems is where these calculations usually go wrong.
Acceleration calculatorCompute acceleration from the change in velocity over time.Angular Velocity CalculatorConvert RPM, rad/s, Hz and period, or derive ω from a linear speed and radius — with tangential speed and centripetal acceleration.Banana radiation (equivalent dose) calculatorPut any radiation dose in perspective with the Banana Equivalent Dose — the tiny ~0.1 µSv you get from the potassium-40 in one banana. Enter a dose in µSv, mSv, Sv, mrem or rem and it converts to bananas, standard units and a plain-language risk band.Bernoulli equation calculatorBernoulli's principle for an ideal fluid: pressure + kinetic + potential head stays constant along a streamline, P + ½ρv² + ρgh = constant. Give the conditions at two points and leave one unknown — pressure, velocity or elevation — and it solves for it, revealing how a pipe that narrows speeds the flow and drops the pressure.BPM delay time calculatorTurn a track's tempo into delay and reverb times in milliseconds.Buoyancy calculatorWill it float or sink? Archimedes' principle: the buoyant force equals the weight of the displaced fluid, F = ρ·V·g. From the fluid density, the object's volume and mass, it computes the buoyant force, the weight, the net force, the object's density, the float/sink verdict and — if it floats — the fraction that sits below the surface.
Amperage CalculatorConvert a load in watts and a supply voltage into the current drawn in amps.Appliance Energy Cost CalculatorTurn any appliance's wattage and daily use into a daily, monthly and yearly running cost in your currency.Appliance running cost calculatorEstimate what an appliance costs to run per day, month and year.Battery life calculatorEstimate how long a battery lasts from its capacity and the load current.Electric field calculator (point charge)The electric field and potential around a point charge: E = k·q / (εᵣ·r²) and V = k·q / (εᵣ·r). Enter the charge, the distance and the surrounding medium — the dielectric weakens the field, water by about 80× — and see the values with SI prefixes plus a field-line diagram.Generator size calculatorEstimate the generator size you need from the wattages of your appliances.
555 timer calculator (astable & monostable)Design a 555 timer circuit in either mode. In astable mode, R1, R2 and C set the output frequency, high and low times and duty cycle; in monostable mode, R1 and C set the one-shot pulse width. The classic hobbyist chip, sized in seconds.Antenna length calculatorCut an antenna to the right size for any frequency. From the wavelength λ = c/f and a velocity factor, it sizes a half-wave dipole, quarter-wave vertical, 5/8-wave vertical or full-wave loop, returning the total length and the per-element length in both metres and feet.Capacitor code calculator (decoder)The three-digit code printed on a ceramic capacitor is picofarads: the first two digits times ten to the third. Enter the code (104 → 100 nF) and get the value in pF, nF and µF.Capacitor energy calculatorCompute the energy stored in a capacitor from its capacitance and voltage (E = ½CV²).Series capacitor calculatorCompute the total capacitance of capacitors connected in series.Impedance calculator (RLC)Compute the impedance of a series or parallel RLC circuit at any frequency. From R, L, C and f it returns the inductive and capacitive reactances, the impedance magnitude |Z|, the phase angle and the resonant frequency where the reactances cancel.
Beer-Lambert law calculatorSolve the Beer-Lambert law A = ε·c·l for any variable — absorbance, molar absorptivity, concentration or path length. Central to spectrophotometry, it links how much light a solution absorbs to how concentrated it is. Pick what to solve for, enter the rest, and read the answer.Boiling point calculator (altitude & pressure)Find the boiling point of water at any altitude or atmospheric pressure. Water boils below 100 °C as you climb because the air pushes down less — this tool converts altitude to pressure with the barometric formula, then to a boiling point via the Clausius-Clapeyron relation. Vital for high-altitude cooking and canning.Boiling point elevation calculatorCompute how much a dissolved solute raises a solvent's boiling point: ΔTb = i·Kb·m, with i the van't Hoff factor, Kb the ebullioscopic constant and m the molality. It returns the elevation and the new boiling point — why salted pasta water boils a touch hotter.Caffeine Half-Life TrackerModel caffeine as exponential decay over your drinks to get the level at bedtime and when it clears.Chemical Equation BalancerBalance any chemical equation instantly by solving the element matrix exactly — even tricky redox reactions.Dilution calculator (C1V1 = C2V2)Find the final volume needed to dilute a solution to a target concentration.
Astronomy (5)
Moon Phase CalculatorFind the moon phase, illumination and lunar age for any date and hemisphere.Star Visibility CalculatorEstimate how many stars you can see from light pollution, moon phase, clouds and humidity.Sun Position CalculatorCompute the sun's azimuth and elevation for any location, date and time.Sunrise & Sunset CalculatorFind sunrise, sunset, solar noon and day length for any location and date.Tide Time CalculatorEstimate the day's high and low tide times from a known reference tide and pattern.