Science calculators
Density, Ohm's law, resistor color, watts to amps, voltage drop, ideal gas, dilution, gears, and related lab arithmetic from values you type. Informational, not wiring or design approval.
45 tools
In this group
Density is mass over volume. Ohm's law solves V, I, R, and P. Resistor color reads IEC 60062 bands. Voltage divider and LED resistor size two common resistor jobs. Watts to amps, amps from kilowatts, and voltage drop stay on the electrical numbers you enter. dBm to watts is a log power conversion. Waves: wavelength and frequency. Motion and machines: kinetic energy, Hooke's law, gear ratio, and RPM surface speed. Ideal gas uses PV = nRT. Dilution uses C1V1 = C2V2. These pages are not a code table, a permit, or a lab protocol.
- Amps to Kilowatts Calculator Current from kilowatts and volts. DC uses I = P / V. Single-phase divides by PF. Three-phase divides by root 3 times V times PF. Informational, not wiring or code approval.
- Amps to kVA Calculator Find apparent kVA from line current and voltage. Single-phase kVA = V × I / 1000. Default 20 A at 240 V gives 4.8 kVA. Informational only.
- Amps to Volt-Amps Calculator Find apparent volt-amperes from current and voltage. Single-phase VA = V × I. Default 15 A at 120 V gives 1800 VA. Informational only.
- Atoms to Moles Calculator Convert a particle count to moles, or moles to particles, using the SI Avogadro constant NA = 6.02214076×10²³ mol⁻¹. Works for atoms, molecules, or formula units.
- Capacitance to Charge Calculator Convert capacitance and voltage to stored charge Q = C × V. Default 100 µF at 12 V gives 0.0012 C (1200 µC). Informational only.
- Coulomb's Law Calculator Compute electrostatic force between two point charges: F = k |q1 q2| / r². Default 1 µC and 1 µC at 0.1 m separation. Uses k = 8.9875517923×10⁹ N·m²/C². Informational physics only.
- dBm to Watts Calculator Convert dBm to watts with P_W = 10^((dBm - 30) / 10). 0 dBm equals 1 mW. Informational, not an RF license or wiring approval.
- Density Calculator Density is mass divided by volume. You get kg/m³, g/cm³, and lb/ft³. This is informational. Density equals specific gravity only when you compare to water at a stated temperature.
- Molarity Dilution Calculator Solve one unknown in C1V1 = C2V2 when concentrations are molarities (mol/L) or any matching concentration unit. Leave exactly one of C1, V1, C2, V2 blank. Not a lab protocol.
- Dilution Calculator Solve one unknown from C1V1 = C2V2. Use the same concentration unit on C1 and C2, and the same volume unit on V1 and V2. Not a lab protocol. Informational, not chemical safety or code approval.
- Ideal Gas Moles Solver Solve the amount of gas n from PV = nRT, or solve pressure, volume, or temperature instead. Defaults target moles. R = 8.314462618 J/(mol·K). Informational, not a pressure-vessel rating.
- Gear Ratio Calculator Ratio = driven teeth / driver teeth. Optional input RPM gives output RPM as input RPM / ratio. Informational, not a gearbox rating or code approval.
- Half-Life Calculator Exponential decay for a single species. Leave exactly one of half-life, elapsed time, initial amount, and remaining amount blank so the page can solve it. Not medical or radiological guidance.
- Hooke's Law Calculator Linear spring force F = k x. Default k = 100 N/m and x = 0.01 m gives 1 N. Informational, not a spring rating, wiring approval, or code approval.
- Ideal Gas Law Calculator Solve one of pressure, volume, amount, or temperature from PV = nRT. R is 8.314462618 J/(mol K). Informational, not a pressure-vessel rating, wiring approval, or lab protocol.
- Joules to Watts Calculator Find average power from energy and time: P = E / t. Default 3600 J over 3600 s gives 1 W. Informational only.
- Kinetic Energy Calculator Translational kinetic energy KE = 1/2 m v squared. Mass in kilograms, speed in meters per second, energy in joules. Informational, not a safety rating or code approval.
- kVA to Amps Calculator Convert apparent kVA to line current with voltage. Single-phase: I = kVA × 1000 / V. Three-phase includes √3. Default 5 kVA at 240 V single-phase is about 20.833 A. Informational only.
- kVA to kW Calculator Find real kilowatts from apparent kVA: kW = kVA × PF. Default 10 kVA at PF 0.85 gives 8.5 kW. Informational only.
- kVA to Watts Calculator Convert apparent kVA to real watts: W = kVA × PF × 1000. Default 3 kVA at PF 0.9 gives 2700 W. Informational only.
- kW to kVA Calculator Convert real power in kilowatts to apparent power in kVA: kVA = kW / PF. Default 5 kW at power factor 0.9 gives 5.556 kVA. Informational only.
- LED Resistor Calculator Series resistor R = (Vs - Vf) / I for one LED on DC. Informational, not a driver design or wiring approval.
- Molality Calculator Solve moles of solute, kilograms of solvent, or molality using m = n / kg solvent. Molality stays stable when temperature changes volume. Informational, not a lab protocol.
- Molar Mass Calculator Type a chemical formula to get molar mass in g/mol. The page parses element symbols and parentheses, then sums IUPAC typical atomic weights. Also called molecular weight for covalent compounds.
- Molarity Calculator Solve any one of moles of solute, solution volume, or molarity using M = n / V. Volume is the total solution volume. Informational, not a lab protocol or chemical safety guide.
- Moles to Grams Calculator Convert moles to grams or grams to moles. Type a molar mass in g/mol, or enter a formula such as H2O so the page sums atomic weights first. Formula: n = m / M.
- Ohm's Law Calculator Solve volts, amps, ohms, and watts from any two of V, I, and R, or from power plus one of those. Informational, not wiring or code approval.
- Parallel Plate Capacitance Calculator Estimate capacitance of parallel plates: C = ε0 εr A / d. Default 0.01 m² area, 1 mm separation, εr = 1 uses vacuum permittivity. Informational lab math only.
- Parallel Resistance Calculator Find equivalent resistance for parallel branches. 1/Rtotal = 1/R1 + 1/R2 + ... + Rn. Three 100 Ω resistors in parallel give 33.333 Ω. Informational only.
- Peak-to-Peak Voltage Calculator Convert RMS or peak voltage to peak-to-peak on a sine. Vpp = 2 × Vpeak = 2√2 × Vrms. Default 120 V RMS gives about 339.4 V peak-to-peak. Informational only.
- Peak Voltage Calculator Find peak voltage from RMS or peak-to-peak on a sinusoidal wave. Vpeak = Vrms × √2. The default 120 V RMS is about 169.7 V peak. Informational, not wiring approval.
- RC Time Constant Calculator Compute τ = R × C for a resistor-capacitor pair. Default 1000 Ω and 10 µF gives τ = 0.01 s. The page also shows 5τ, about 99.3% of full charge on an ideal step. Informational only.
- Resistor Color Code Calculator Read 4-band and 5-band resistor values from IEC 60062 colors. Informational, not a wattage rating or wiring approval.
- RMS Voltage Calculator Convert peak or peak-to-peak voltage to RMS for a sinusoidal wave. Vrms = Vpeak / √2. The default 170 V peak matches a 120 V RMS household sine. Informational, not wiring approval.
- RPM Calculator Surface speed from diameter and RPM: v = pi d n / 60, with n in revolutions per minute. Enter exactly two of diameter, RPM, and speed. Informational, not a machine rating or code approval.
- Series Resistance Calculator Add resistances in series. Rtotal = R1 + R2 + ... + Rn. Default list 100, 220, 330 Ω sums to 650 Ω. Informational, not a BOM checker.
- VA to kW Calculator Convert volt-amperes to real kilowatts: kW = VA × PF / 1000. Default 5000 VA at PF 0.88 gives 4.4 kW. Informational only.
- Volt-Amps to Amps Calculator Convert volt-amperes to current: I = VA / V on single-phase. Default 1800 VA at 120 V gives 15 A. Informational only.
- Voltage Divider Calculator Unloaded divider Vout = Vin times R2 / (R1 + R2). Informational, not wiring or code approval.
- Voltage Drop Calculator Conductor voltage drop at 20 °C. Informational, not a code table.
- Watts to Amps Calculator Current from power and voltage. Informational, not wiring advice.
- Watts to Joules Calculator Convert power over time to energy: E = P × t. Default 100 W for 60 seconds gives 6000 J (6 kJ). Informational physics and billing prep only.
- Watts to kVA Calculator Convert real watts to apparent kVA: kVA = (W / 1000) / PF. Default 2400 W at PF 0.9 gives 2.667 kVA. Informational only.
- Wavelength Frequency Calculator Solve c = f lambda. Default wave speed is 299792458 m/s, the speed of light in vacuum. Enter frequency or wavelength. Informational, not a radio license or wiring approval.
- Wire Ampacity Calculator Look up NEC 310.16 style ampacity by AWG, material, and temperature column. Default 12 AWG copper at 75 °C uses the table ampacity with optional derating. Informational, not code approval.