Science
Physics, chemistry, astronomy, meteorology and ecology calculators. Every page below is currently a stub: the working tool, its formula and its worked example are published one calculator at a time, and a page is listed in the index allowlist only once it is finished.
246 calculators in 26 subjects.
Agriculture and energy
- Chill Hours and Chill Units Calculatorstub
- Frost Risk and Radiative Cooling Calculatorstub
- Hargreaves Evapotranspiration Calculatorstub
- Heating and Cooling Degree Days Calculatorstub
- Optimal Solar Panel Tilt Angle Calculatorstub
- Reference Evapotranspiration Penman Monteith Calculatorstub
- Solar Irradiance and Peak Sun Hours Calculatorstub
- UV Index Exposure and Sunburn Time Calculatorstub
- Vitamin D Sun Exposure Time Calculatorstub
- Weather Station Data Averaging and Anomaly Calculatorstub
Atmosphere
- Air Density Calculatorstub
- Air Pressure Unit Converterstub
- Altitude from Barometric Pressure Calculatorstub
- Barometric Pressure Sea Level Adjustment Calculatorstub
- CAPE and Convective Instability Estimatorstub
- Cloud Base Height Calculatorstub
- Lapse Rate and Temperature at Altitude Calculatorstub
- Lifted Condensation Level Calculatorstub
- Lightning Strike Risk and Safe Return Time Calculatorstub
- Potential Temperature and Equivalent Potential Temperature Calculatorstub
- Storm Distance from Lightning and Thunder Calculatorstub
Biodiversity
- Berger Parker and Margalef Index Calculatorstub
- Ecological Niche Overlap Calculatorstub
- Importance Value Index for Plants Calculatorstub
- Jaccard and Sorensen Similarity Index Calculatorstub
- Shannon Wiener Diversity Index Calculatorstub
- Simpson Diversity Index Calculatorstub
- Species Richness and Rarefaction Calculatorstub
- Trophic Level and Ecological Efficiency Calculatorstub
Chemistry
- Boiling Point Elevation And Freezing Point Depression Calculatorstub
- Buffer pH Calculator (Henderson-Hasselbalch)stub
- Chemical Equation Balancerstub
- Dilution Calculator (C1V1 = C2V2)stub
- Empirical And Molecular Formula Calculatorstub
- Equilibrium Constant Calculator (Kc And Kp)stub
- Molality And Normality Calculatorstub
- Molar Mass Calculatorstub
- Molarity Calculatorstub
- Nernst Equation And Cell Potential Calculatorstub
- Partial Pressure Calculator (Dalton's Law)stub
- Percentage Composition Calculatorstub
- Percentage Yield Calculatorstub
- pH And pOH Calculatorstub
- PPM And Trace Concentration Calculatorstub
- Reaction Rate And Arrhenius Equation Calculatorstub
- Stoichiometry And Limiting Reagent Calculatorstub
- Thermochemistry And Hess's Law Calculatorstub
- Titration Calculatorstub
Distance and scale
- Angular Size and Physical Size Calculatorstub
- Astronomical Unit Converterstub
- Cosmological Lookback Time Calculatorstub
- Hubble Law Expansion Calculatorstub
- Light Travel Time Calculatorstub
- Light Year to Kilometers Miles and Parsec Converterstub
- Redshift to Distance and Recession Velocity Calculatorstub
- Scale Model Solar System Calculatorstub
- Stellar Parallax to Distance Calculatorstub
Human comfort
- Apparent Temperature and Humidex Calculatorstub
- Frostbite Time Calculatorstub
- Heat Index Calculatorstub
- Heat Stress Work Rest Cycle Calculatorstub
- Hydration Requirement in Heat Calculatorstub
- Wet Bulb Globe Temperature Calculatorstub
- Wet Bulb Temperature Calculatorstub
- Wind Chill Temperature Calculatorstub
Humidity
- Absolute Humidity and Vapor Density Calculatorstub
- Condensation and Mold Risk Surface Temperature Calculatorstub
- Dehumidifier Capacity Sizing Calculatorstub
- Dew Point Calculatorstub
- Humidifier Output Requirement Calculatorstub
- Relative Humidity from Dew Point Calculatorstub
- Saturation Vapor Pressure Calculatorstub
- Specific Humidity and Mixing Ratio Calculatorstub
Orbits
- Bi Elliptic Transfer Comparison Calculatorstub
- Escape Velocity Calculatorstub
- Geostationary Orbit Altitude Calculatorstub
- Hohmann Transfer Delta V Calculatorstub
- Kepler Third Law Orbital Period Calculatorstub
- Lagrange Point Position Calculatorstub
- Launch Window and Synodic Period Calculatorstub
- Orbital Decay and Reentry Time Estimatorstub
- Orbital Velocity Calculatorstub
- Plane Change Delta V Calculatorstub
- Roche Limit Calculatorstub
- Satellite Ground Track and Revisit Period Calculatorstub
- Satellite Pass Visibility and Footprint Calculatorstub
- Sphere of Influence and Hill Radius Calculatorstub
- Synchronous Orbit for Any Planet Calculatorstub
Physics: fluid mechanics
Physics: mechanics
- Angular Momentum Calculatorstub
- Centripetal Force And Circular Motion Calculatorstub
- Collision Calculator (Elastic And Inelastic)stub
- Density, Mass And Volume Calculatorstub
- Force Calculator (Newton's Second Law)stub
- Free Fall Calculatorstub
- Friction Calculatorstub
- Gravitational Force And Orbital Mechanics Calculatorstub
- Inclined Plane Calculatorstub
- Kinematics Calculator (Equations Of Motion)stub
- Kinetic And Potential Energy Calculatorstub
- Mass Moment Of Inertia Calculatorstub
- Momentum And Impulse Calculatorstub
- Power Calculator (Mechanical And Electrical)stub
- Projectile Motion Calculatorstub
- Rotational Motion Calculatorstub
- Torque Calculatorstub
- Work And Energy Calculatorstub
Physics: modern physics
Physics: optics
Physics: thermodynamics
Physics: waves and oscillations
Planets and gravity
- Exoplanet Habitable Zone Calculatorstub
- Exoplanet Transit Depth and Radius Calculatorstub
- Gravitational Force Between Two Masses Calculatorstub
- Gravitational Potential Energy and Binding Energy Calculatorstub
- Planetary Density and Composition Calculatorstub
- Radial Velocity Planet Mass Calculatorstub
- Surface Gravity Calculatorstub
- Weight on Other Planets Calculatorstub
Pollution
- Air Purifier CADR and Room Sizing Calculatorstub
- Air Quality Index Concentration Converterstub
- Biochemical Oxygen Demand Calculatorstub
- Decibel Addition of Multiple Noise Sources Calculatorstub
- Dissolved Oxygen Saturation Calculatorstub
- Indoor CO2 Ventilation Rate Calculatorstub
- Landfill Methane Generation Calculatorstub
- Noise Decibel Distance Attenuation Calculatorstub
- Noise Exposure Dose and Time Weighted Average Calculatorstub
- Plastic Waste and Recycling Diversion Rate Calculatorstub
- PM2.5 Exposure and Cigarette Equivalent Calculatorstub
- Reverberation Time Sabine Calculatorstub
- Sound Transmission and Wall Insulation Calculatorstub
- Wastewater Treatment Plant Loading Calculatorstub
- Water Quality Index Calculatorstub
Population ecology
- Doubling Time and Intrinsic Growth Rate Calculatorstub
- Exponential and Logistic Population Growth Calculatorstub
- Life Table and Survivorship Curve Calculatorstub
- Lincoln Petersen Capture Recapture Population Calculatorstub
- Maximum Sustainable Yield Calculatorstub
- Minimum Viable Population and Effective Population Size Calculatorstub
- Net Reproductive Rate and Generation Time Calculatorstub
- Population Density and Home Range Calculatorstub
- Schnabel Multiple Census Population Calculatorstub
Precipitation
- Coastal Flood Total Water Level Calculatorstub
- Flood Return Period and Exceedance Probability Calculatorstub
- Gutter and Downspout Sizing Calculatorstub
- Hail Size and Impact Energy Calculatorstub
- Ice Accretion Load on Power Lines Calculatorstub
- Rainfall Intensity Duration Frequency Calculatorstub
- Rainfall Volume and Catchment Runoff Calculatorstub
- Rainwater Harvesting Tank Size Calculatorstub
- Rational Method Peak Flow Calculatorstub
- SCS Curve Number Runoff Calculatorstub
- Snow Load on a Roof Calculatorstub
- Snow to Rain Ratio Converterstub
- Snow Water Equivalent Calculatorstub
- Storm Surge Height Estimatorstub
Relativity
- Gravitational Time Dilation Calculatorstub
- Hawking Radiation Temperature and Evaporation Time Calculatorstub
- Interstellar Travel Time with Relativity Calculatorstub
- Relativistic Kinetic Energy and Momentum Calculatorstub
- Schwarzschild Radius and Black Hole Property Calculatorstub
- Special Relativistic Time Dilation and Length Contraction Calculatorstub
Renewables and waste
- Biogas and Anaerobic Digester Yield Calculatorstub
- Compost Pile Volume and Moisture Calculatorstub
- Firewood Cord Volume and Heat Value Calculatorstub
- Heat Pump Efficiency and Running Cost Calculatorstub
- Home Battery Storage Sizing and Payback Calculatorstub
- Home Insulation Payback and Heat Loss Calculatorstub
- Micro Hydro Power Output Calculatorstub
- Renewable Energy Payback and EROI Calculatorstub
- Solar Panel System Size and Output Calculatorstub
- Solar Payback Period and Return Calculatorstub
- Wood Pellet and Fuel Cost Comparison Calculatorstub
Rocketry
- Gravity Losses and Ideal versus Actual Delta V Calculatorstub
- Model Rocket Apogee and Descent Rate Calculatorstub
- Multi Stage Rocket Delta V Budget Calculatorstub
- Propellant Mass Required Calculatorstub
- Specific Impulse and Exhaust Velocity Converterstub
- Thrust to Weight and Liftoff Acceleration Calculatorstub
- Tsiolkovsky Rocket Equation Delta V Calculatorstub
Sky events
- Eclipse Magnitude and Obscuration Calculatorstub
- Equation of Time and Solar versus Clock Time Calculatorstub
- Golden Hour and Blue Hour Calculatorstub
- Julian Date and Sidereal Time Converterstub
- Light Pollution Bortle Class and Limiting Magnitude Calculatorstub
- Meteor Shower Zenithal Hourly Rate Calculatorstub
- Moon Phase and Illumination Calculatorstub
- Moonrise Moonset and Moon Altitude Calculatorstub
- Shadow Length from Sun Elevation Calculatorstub
- Solar Position Azimuth and Elevation Calculatorstub
- Twilight Times Civil Nautical and Astronomical Calculatorstub
Stars
- Apparent and Absolute Magnitude Distance Modulus Calculatorstub
- Doppler Shift and Radial Velocity Calculatorstub
- Magnitude to Brightness Ratio Calculatorstub
- Main Sequence Lifetime Calculatorstub
- Stellar Color Index and Temperature Calculatorstub
- Stellar Luminosity from Radius and Temperature Calculatorstub
- Stellar Mass Luminosity Relation Calculatorstub
- Wien Displacement Peak Wavelength Calculatorstub
Telescopes
- 500 Rule Star Trail Exposure Calculatorstub
- Astrophotography Field of View and Image Scale Calculatorstub
- Deep Sky Total Integration Time Calculatorstub
- Exit Pupil and Eyepiece Selection Calculatorstub
- Limiting Magnitude and Light Grasp Calculatorstub
- Polar Alignment Error and Drift Calculatorstub
- Telescope Focal Ratio and Aperture Calculatorstub
- Telescope Magnification Calculatorstub
- Telescope Resolving Power and Dawes Limit Calculatorstub
- True Field of View Calculatorstub
Water and land
- Earth Overshoot Day Calculatorstub
- Ecological Footprint in Global Hectares Calculatorstub
- Forest Biomass and Timber Volume Calculatorstub
- Green Roof Stormwater Retention Calculatorstub
- Greywater Reuse Volume Calculatorstub
- Household Water Use and Savings Calculatorstub
- Land Required to Feed a Person Calculatorstub
- Rain Garden and Bioswale Sizing Calculatorstub
- Soil Carbon Sequestration Calculatorstub
- Tree Carbon Sequestration Calculatorstub
- Trees Needed to Offset Emissions Calculatorstub
- Urban Tree Canopy Cover and Cooling Benefit Calculatorstub
- Water Footprint of Food Calculatorstub
Wind
- Beaufort Scale and Wind Damage Estimatorstub
- Design Wind Load on a Building Calculatorstub
- Gust Factor and Peak Wind Estimatorstub
- Wind Farm Capacity Factor and Annual Energy Calculatorstub
- Wind Pressure and Force on a Surface Calculatorstub
- Wind Speed at Height Power Law Calculatorstub
- Wind Speed Unit Converterstub
- Wind Turbine Power Output Calculatorstub