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Science & Engineering

105 free online calculators — instant results, no sign-up

All 105 Science & Engineering Tools

Wall U-Value Calculator

GB 50176 layered thermal resistance

Rocket Delta-V Calculator

Tsiolkovsky equation

Diving Gas Planner

SAC × depth factor → bottom time

Steel Weight Calculator

Round bar, pipe and plate per meter

Ohm's Law Calculator

V=IR — solve any two of voltage, current, resistance

Electric Power Calculator

P=VI, energy consumption and electricity cost

Resistor Series & Parallel Calculator

Equivalent resistance comparison

Engine Displacement Calculator

Bore × stroke × cylinders, cc/liters

Renovation Cost Estimator

Full/half-package estimate by floor area

Tile Quantity Calculator

Pieces, boxes and total cost

Wavelength Calculator

Frequency to wavelength — λ=c/f

Force Calculator

F=ma — Newton's second lawNEW

Density Calculator

ρ=m/V — density, mass and volume

Speed of Sound Calculator

Sound speed from air temperature

Paint Calculator

Liters and buckets from area and coats

Flooring Calculator

Purchase area with waste allowance from room size

Half-Life Calculator

Remaining amount or required time for radioactive decay and drug metabolism

Molar Mass Calculator

Molecular weight from chemical formula with element breakdown

Free Fall Calculator

Height, time and impact velocity on Earth, Moon or Mars

Ideal Gas Law Calculator

PV = nRT — solve pressure, volume, moles or temperature

Dilution Calculator

C1V1 = C2V2 for stock volume, final concentration or volume

Kinetic & Potential Energy

Ek=½mv² and Ep=mgh with real-world equivalents

Heat Capacity Calculator

Q=cmΔT heat energy and heating time estimate

Lightning Distance Calculator

Flash-to-thunder seconds to distance, safety rules

Lightning Rod Protection Calculator

GB 50057 rolling sphere, hr = 30/45/60 m, radius at hx

Earthquake Energy Calculator

Energy ratio between magnitudes, lgE=4.8+1.5M

Star Magnitude Brightness Calculator

Pogson ratio 2.512^Δm and combined double-star magnitude

Note Frequency Calculator

Equal temperament f=440×2^(n/12) with cents detune

Crop Factor & EFL Calculator

Sensor crop factor, equivalent focal length and FOV

Acceleration Calculator

Solve a, v, u, t, s with kinematic equations

Projectile Motion Calculator

Range, max height and flight time at any angle

pH Calculator

pH, pOH, H+ concentration and acid dilution

Velocity Calculator

Solve v, s, t — three-way with unit conversion

Momentum Calculator

p=mv, impulse and impact force

Potential Energy Calculator

Ep=mgh with multi-planet gravity

LED Resistor Calculator

Nearest E24 value and power rating

Voltage Divider Calculator

Vout=Vin·R2/(R1+R2), forward and reverse

Battery Life Calculator

mAh ÷ mA with real-world derating

Charging Time Calculator

EV and phone charging hours with 90% efficiency

Solar Panel Output Calculator

Capacity x peak sun hours x system efficiency, regional guide

Wind Chill & Heat Index Calculator

Feels-like temperature — Canadian & NOAA formulas

Wind Scale Converter

Beaufort force 0-17 from wind speed with land conditions

Rainfall Scale Classifier

GB/T 28592 six grades on 12h/24h windows

Weight on Other Planets

Your weight on 11 solar system bodies

Geo Distance Calculator

Haversine great-circle distance, city presets

Decibel Calculator

dB to ratio, multi-source summation

Pendulum Period Calculator

T=2π√(L/g), multiple planets

Centripetal Force Calculator

F=mv²/r, rpm conversion, g-force

Depth of Field Calculator

Hyperfocal distance, full frame/APS-C presets

RC Circuit Calculator

Time constant, charging curve

Hooke's Law Calculator

F=kx, elastic potential energy

Kepler's Third Law Calculator

T²=a³, planet table

Buoyancy Calculator

Archimedes principle, float or sink

Resistor Color Code

4/5-band decode & encode, E24 series

Exposure Calculator (EV)

EV value, equivalent combos, ND stops

Heat Index Calculator

NOAA feels-like temp, risk levels

Dew Point Calculator

T+RH ↔ dew point, condensation check

Transformer Calculator

Turns ratio, voltage & current

Lens Calculator

1/f=1/u+1/v, image type, magnification

Pressure Calculator

P=F/S and liquid P=ρgh

Lever Calculator

F1·L1=F2·L2, three lever types

Pulley Calculator

Force saving, mechanical efficiency

Molarity Calculator

mol/L, mass fraction, ppm conversion

Empirical Formula Calculator

Element masses → mole ratio → simplest formula

Friction Calculator

Static/kinetic friction + incline

Torque Calculator

τ=rF·sinθ, power-speed conversion

Refraction Calculator

Snell's law + critical angle

Reverberation Time Calculator

Sabine RT60 = 0.161V/A with room recommendations

Sound Insulation Calculator

Mass law R = 20lg(mf) - 48, single/double leaf with air gap

Illumination Calculator

GB/T 50034 lux standards, lumen method, luminaire count

Mass-Energy Calculator

E=mc² + TNT equivalent

Gravitational Force Calculator

F=GmM/r² + surface gravity

Three-Phase Power Calculator

P=√3UIcosφ + star/delta

Gear Ratio Calculator

Teeth/speed/torque + multi-stage

LC Resonance Calculator

f=1/(2π√LC) + 3-way solver

Pipe Flow Calculator

Q=vA + sizing + velocity guide

Time Dilation Calculator

Lorentz factor + twin paradox

Doppler Effect Calculator

Source/observer + frequency shift

Thermal Expansion Calculator

dL=a*L*dT · material alpha table

Centrifuge RPM-RCF Converter

Bidirectional · protocol reference

Voltage Drop Calculator

Single/three-phase · wire sizing · 5% rule

Battery Pack S×P Calculator

Series×parallel pack voltage, Ah, Wh, cell count

Stopping Distance Calculator

Reaction + braking · surface friction

Chemical Equation Balancer

Balance any equation · conservation check · steps

Stoichiometry Calculator

Auto-balance · mass/moles/gas volume from coefficients

Work & Power Calculator

W=Fs·cosθ · P=W/t · P=Fv · kWh/horsepower

Net Force Calculator

Parallelogram rule · direction angle · special cases

Escape Velocity Calculator

Second cosmic velocity · any body by mass & radius

Carnot Efficiency Calculator

Heat engine efficiency ceiling · 1 − Tc/Th

Bernoulli Equation Calculator

P + ½ρv² + ρgh conservation · pipe pressure difference

Capacitor Energy Calculator

E = ½CV² · stored charge · supercaps & electrolytics

Inductor Energy Calculator

E = ½LI² · magnetic storage · switching converters

Impulse & Momentum Calculator

Ft = mΔv · crash cushioning · airbag principle

G-Force Calculator

Acceleration → g · elevators, fighters, racing

Hydrostatic Pressure Calculator

P = ρgh · dams, diving, tanks

Newton's Law of Cooling Calculator

T(t)=Ta+(T0−Ta)e^(−kt) · food safety & annealing

Grams ⇄ Moles Converter

n=m/M two-way · molar mass · stoichiometry basic

Titration Calculator

cₐVₐ·nₐ=c_bV_b·n_b · acid-base · standardization

Colligative Properties Calculator

ΔTf=Kf·m freezing depression · boiling elevation

Buffer pH Calculator

Henderson-Hasselbalch · pH=pKa+lg(A⁻/HA)

Serial Dilution Calculator

Cₙ=C₀/Dⁿ · step dilution · MIC & ELISA plates

Hardy-Weinberg Calculator

p²+2pq+q²=1 · allele frequencies · carrier rate

Cell Doubling Calculator

N=N₀·2^(t/Td) · culture planning · passages

qPCR Efficiency Calculator

E=(10^(−1/slope)−1)×100% · standard curve · 90-110%

Beam Deflection Calculator

Simply supported beam under uniform load

Related Guides

Ohm's Law: V=IR Formulas, Wheel & Power Calculations

V = I × R links voltage, current and resistance; P = V × I gives power. 12V across 10Ω → 1.2A, 14.4W. Includes the 12-formula wheel, series vs parallel examples, wire sizing intuition and why LEDs need resistors.

Equivalent Resistance: Simplify Series-Parallel & Bridge Circuits

Series resistances add (R = R1 + R2); parallel reciprocals add (1/R = 1/R1 + 1/R2). Two 10Ω: 20Ω series, 5Ω parallel. Includes the product-over-sum shortcut, n-resistor formulas, mixed-network reduction steps and voltage divider design.

Renovation Budget: Price Tiers & Where the Money Goes

Full renovation runs ¥1,000-3,000/sqm: basic ¥1-1.5k, mid ¥1.5-2.5k, high-end ¥3k+. A 100sqm mid-tier = ¥150-250k split roughly: labor 30%, materials 40%, furniture/appliances 20%, contingency 10%. Full allocation tables inside.

Tile Quantity Calculator: Coverage, Waste & Box Math

Tiles needed = area ÷ tile area × (1 + waste 5-15%). 20sqm floor with 600×600mm tiles: 20 ÷ 0.36 × 1.08 ≈ 60 tiles. Covers waste rates by pattern, box rounding, and the extra-box rule for future repairs.

Ohm's Law: U=IR Formulas & Circuit Examples

U = I × R — voltage = current × resistance. Any two give the third: I = U/R, R = U/I. 12V across 4Ω → 3A; power P = UI = I²R = U²/R → 36W. Includes the power triangle, series/parallel voltage-current rules and household safety math.

Wavelength & Frequency: λ = v/f and the EM Spectrum

λ = v/f: wavelength = wave speed ÷ frequency. Sound (343 m/s) at 1 kHz → 34.3 cm; light (3×10⁸ m/s) at 100 MHz → 3 m. The EM spectrum from radio to gamma is one formula wide. Includes music acoustics, antenna sizing and color wavelengths.