Gravity Calculator
Calculate acceleration due to gravity, specific gravity, beer gravity, center of gravity, and more with our comprehensive gravity calculator
What is a Gravity Calculator?
A gravity calculator is a powerful tool designed to compute various types of gravity-related values. Whether you need to calculate acceleration due to gravity, specific gravity for liquids and solids, beer gravity for brewing purposes, or center of gravity for physics problems, this calculator handles them all with precision and ease.
Our calculator supports multiple measurement units, provides detailed formulas, and offers instant results for professional, academic, and hobbyist use.
Acceleration Due to Gravity Calculator
Calculate the acceleration due to gravity at any location on Earth using Newton's law of universal gravitation.
Formula: g = GM/r²
Where: G = 6.674 × 10⁻¹¹ m³/(kg·s²) (gravitational constant)
M = mass of Earth (5.972 × 10²⁴ kg)
r = distance from Earth's center
Did You Know?
Acceleration due to gravity varies by location! At sea level, it's 9.81 m/s², but at the poles it's about 9.83 m/s² and at the equator it's about 9.78 m/s². This difference is due to Earth's rotation and oblate shape.
Gravity Values at Different Locations
| Location | Latitude | Acceleration (m/s²) |
|---|---|---|
| Equator | 0° | 9.7803 |
| New York | 40.7°N | 9.8017 |
| London | 51.5°N | 9.8121 |
| North Pole | 90°N | 9.8322 |
| Mount Everest | 28°N, 8848m alt | 9.7645 |
Specific Gravity Calculator
Calculate specific gravity by comparing the density of any substance to the density of water at 4°C.
Formula: SG = ρ_substance / ρ_water
Where: ρ_substance = density of the substance
ρ_water = 1000 kg/m³ (density of water at 4°C)
Specific Gravity Reference Table
| Substance | Specific Gravity | State |
|---|---|---|
| Water (4°C) | 1.000 | Liquid |
| Ice | 0.917 | Solid |
| Aluminum | 2.700 | Solid |
| Iron | 7.874 | Solid |
| Gold | 19.300 | Solid |
| Ethanol | 0.789 | Liquid |
| Mercury | 13.546 | Liquid |
| Olive Oil | 0.915 | Liquid |
Applications of Specific Gravity
- Quality control in manufacturing and food production
- Determining if objects will float or sink in water
- Measuring and controlling density in various liquids
- Gemstone and mineral identification
- Pharmaceutical and chemical industry applications
- Determining solution concentration
Beer Gravity & ABV Calculator
Calculate Original Gravity (OG), Final Gravity (FG), ABV (Alcohol by Volume), and other brewing parameters with precision.
ABV Formula: ABV = (OG - FG) × 131.25
Alternative: ABV = (76.08 × (OG - FG)) / (1.65 - OG)
Where: OG = Original Gravity (starting gravity)
FG = Final Gravity (ending gravity after fermentation)
Understanding Beer Gravity
Original Gravity (OG): The gravity of wort before fermentation begins. Higher OG means more fermentable sugars.
Final Gravity (FG): The gravity after fermentation is complete. Shows how much sugar was converted to alcohol.
Alcohol by Volume (ABV): The percentage of alcohol in the finished beer. Most beers range from 3-8% ABV.
Beer Style ABV Ranges
| Beer Style | Typical ABV Range | Typical OG Range |
|---|---|---|
| Light Lager | 3.5% - 4.5% | 1.040 - 1.050 |
| Pale Ale | 4.5% - 6.0% | 1.048 - 1.065 |
| IPA | 6.0% - 8.5% | 1.060 - 1.080 |
| Stout | 5.5% - 7.5% | 1.055 - 1.075 |
| Imperial Stout | 8.0% - 12.0% | 1.080 - 1.120 |
| Barleywine | 9.0% - 15.0% | 1.090 - 1.150 |
Brewing Tips
- Higher OG typically produces higher alcohol content and fuller flavor
- Attenuation refers to how much yeast reduces gravity (FG/OG)
- Most ale yeasts attenuate 70-75%, lagers 65-75%
- Use hydrometers or refractometers for accurate gravity readings
- Temperature affects hydrometer readings; always correct to 20°C (68°F)
- Calibrate your measuring equipment regularly for accuracy
Center of Gravity Calculator
Calculate the center of gravity for composite objects and systems of masses in 2D and 3D coordinates.
Formula for 2D: X_cg = (Σ m_i × x_i) / Σ m_i
Y_cg = (Σ m_i × y_i) / Σ m_i
Where: m_i = mass of each object
x_i, y_i = coordinates of each mass
What is Center of Gravity?
The center of gravity is the point where the entire mass of an object can be considered to act. It's crucial in engineering, physics, and design for understanding stability, motion, and balance.
Applications of Center of Gravity Calculations
- Aerospace engineering for aircraft balance and stability
- Automotive design for vehicle handling and safety
- Sports science for athlete performance optimization
- Structural engineering for building and bridge design
- Marine engineering for ship stability
- Robotics and mechanical design
Center of Gravity Formulas by Shape
| Shape | Center of Gravity Location | Formula/Distance |
|---|---|---|
| Rectangle | Center point | h/2, w/2 |
| Triangle | Centroid | h/3 from base |
| Circle | Center | At radius r |
| Semicircle | Along axis | 4r/(3π) |
| Sphere | Center | At radius r |
API Gravity Calculator
Calculate API Gravity for petroleum products. API gravity measures how light or heavy petroleum is compared to water.
Formula: °API = (141.5 / Specific Gravity) - 131.5
Inverse: SG = 141.5 / (°API + 131.5)
Where: SG = Specific Gravity (at 60°F/15.6°C)
Oil Classification by API Gravity
| Classification | API Gravity Range | Density Range |
|---|---|---|
| Extra Heavy | < 10°API | > 0.920 g/cm³ |
| Heavy | 10° - 22.3°API | 0.820 - 0.920 g/cm³ |
| Medium | 22.3° - 31.1°API | 0.745 - 0.820 g/cm³ |
| Light | 31.1° - 42.3°API | 0.635 - 0.745 g/cm³ |
| Extra Light | > 42.3°API | < 0.635 g/cm³ |
Why is API Gravity Important?
- Determines market value and price of crude oil
- Indicates refinery processing requirements
- Affects product yield and quality
- Used for standardization in petroleum industry
- Essential for trading and commerce standards
Why Should You Use This Gravity Calculator?
Accurate Calculations
Get precise results instantly with our advanced algorithms and scientific formulas.
Multiple Applications
Handle physics, brewing, petroleum, and engineering calculations all in one tool.
User-Friendly Interface
Easy-to-use design makes complex calculations accessible to everyone.
Educational Value
Learn gravity concepts with detailed formulas and explanations for every calculation.
Unit Conversions
Automatically convert between SI, imperial, and other measurement systems.
Free & Accessible
No registration required. Use our gravity calculator anytime, anywhere, on any device.
Frequently Asked Questions
Gravity is the natural force of attraction between two objects with mass. The acceleration due to gravity on Earth's surface is approximately 9.81 m/s². It's calculated using Newton's law of universal gravitation: g = GM/r², where G is the gravitational constant, M is the mass of Earth, and r is the distance from Earth's center.
Original Gravity (OG) is the gravity of the wort before fermentation begins and indicates the amount of fermentable sugars present. Final Gravity (FG) is the gravity after fermentation is complete and shows how much sugar has been converted to alcohol and CO2. The difference between OG and FG determines the alcohol by volume (ABV) of the beer.
Specific gravity can be measured using several instruments: Hydrometers (for liquids), Pycnometers (for high accuracy), Refractometers (quick readings), or by calculating from density measurements. For accurate results, ensure proper temperature correction (typically 4°C or 20°C for reference), clean equipment, and proper technique. Always follow instrument-specific calibration procedures.
Key formulas include: Acceleration due to gravity (g = GM/r²), Specific gravity (SG = ρ_substance / ρ_water), Beer ABV ((OG - FG) × 131.25), API gravity (°API = (141.5/SG) - 131.5), and Center of gravity (X_cg = Σ(m_i × x_i) / Σm_i). Each formula applies to different types of gravity calculations and applications.
Acceleration due to gravity varies with latitude because: (1) Earth is oblate (flattened at poles), so distance from Earth's center is less at the poles, and (2) Earth's rotation creates centrifugal effects that are strongest at the equator. As a result, g is approximately 9.78 m/s² at the equator and 9.83 m/s² at the poles.
API gravity indicates how light or heavy crude oil is. Higher API values mean lighter oil (better quality and higher market value). The scale ranges from below 10°API (extra heavy) to above 42.3°API (extra light). Lighter oils produce more valuable products during refining and are easier to process, making API gravity a critical factor in oil pricing and refinery decisions.
Yes! This gravity calculator is perfect for academic purposes, including homework, lab reports, exam preparation, and research. It provides accurate calculations based on scientific formulas and includes detailed explanations and reference tables. However, always verify results independently and understand the underlying concepts for your field of study.
Our calculator supports multiple unit systems including: SI units (m/s², kg, m³, etc.), Imperial units (ft/s², lb, ft³), and specialized units (degrees API, Brix, specific gravity). Most inputs allow unit selection, and results are displayed in multiple formats for convenience and international compatibility.
Our calculations use scientifically proven formulas and maintain high precision (typically to 4-6 decimal places). However, real-world accuracy depends on input data quality and measurement conditions. For critical applications, always verify results with proper laboratory equipment and follow industry-specific standards and calibration procedures.
Comprehensive Guide to Gravity
Gravity in Physics
Gravity is one of the four fundamental forces in physics and is responsible for the attraction between objects with mass. On Earth, it gives weight to physical objects and causes them to fall toward the ground at an acceleration of approximately 9.81 m/s². This force was first quantified by Isaac Newton through his law of universal gravitation and later refined by Albert Einstein's theory of general relativity.
Acceleration Due to Gravity
Acceleration due to gravity (represented as 'g') varies depending on location. At sea level, the standard value is 9.81 m/s², but this changes with altitude and latitude. At higher altitudes, gravity is weaker because you're farther from Earth's center. At the equator, gravity is slightly weaker (9.78 m/s²) compared to the poles (9.83 m/s²) due to Earth's rotation and oblate shape.
Specific Gravity and Density
Specific gravity compares the density of any substance to the density of water. A specific gravity less than 1 means the substance is less dense than water and will float. A specific gravity greater than 1 means the substance is denser than water and will sink. This property is crucial in many applications, from identifying minerals to controlling chemical processes.
Beer Gravity and Brewing
In brewing, gravity measurements are essential for predicting and monitoring fermentation. The Original Gravity (OG) measures the concentration of fermentable sugars in the wort before yeast is added. As yeast ferments these sugars, they're converted into alcohol and carbon dioxide, causing the gravity to decrease until reaching Final Gravity (FG). The difference between OG and FG directly correlates to the alcohol content of the finished beer.
Center of Gravity Applications
The center of gravity is the point where the entire weight of an object can be considered to act. Understanding where this point is located is critical in engineering and physics. In aircraft design, the center of gravity must be within a specific range for the plane to be stable and controllable. In vehicles, proper weight distribution affects handling and safety. In biomechanics, analyzing the center of gravity helps optimize athletic performance.
API Gravity in the Petroleum Industry
API gravity is a measure developed by the American Petroleum Institute to classify crude oil. The scale is inverse to specific gravity, meaning lighter oils have higher API values and are more valuable. Light crude oil (higher API) is easier to refine and produces more gasoline and diesel, while heavy crude requires more processing and produces more fuel oil and bitumen.
Additional Resources
- NIST (National Institute of Standards and Technology) - Official gravity and physics reference standards
- American Petroleum Institute - API gravity classification standards and specifications
- Master Brewers Association - Beer gravity and brewing calculation resources
- International System of Units (SI) - Official metric system standards and conversions
- Physics Textbooks - Newton's laws and gravitational theory fundamentals
- Laboratory Equipment Manufacturers - Hydrometer and refractometer calibration guides
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