Acceleration is the rate of change of velocity with respect to time. It is a vector quantity with both magnitude and direction. In the International System of Units (SI), acceleration is measured in meters per second squared (m/s²). One m/s² means an object's velocity increases by 1 meter per second every second. Acceleration occurs whenever an object changes its speed, direction, or both. It is calculated using the formula: a = Δv / Δt (change in velocity divided by change in time).
SI Units Converter
Convert between meter per second squared, kilometer per second squared, and other SI acceleration units with scientific precision.
Conversion Formula
1 m/s² = 1 m/s²
Common Conversions
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What is Acceleration?
Acceleration is the rate of change of velocity with respect to time. It is a vector quantity, meaning it has both magnitude and direction. In the International System of Units (SI), acceleration is measured in meters per second squared (m/s²). One m/s² means an object's velocity increases by 1 meter per second every second.
Acceleration occurs whenever an object changes its speed, direction, or both. For example, a car speeding up from 0 to 60 mph, a planet orbiting the sun (centripetal acceleration), or an apple falling from a tree (gravitational acceleration) all involve acceleration.
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Linear Acceleration Change in speed along a straight path. Formula: a = Δv / Δt
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Angular Acceleration Change in rotational speed. Measured in rad/s². Formula: α = Δω / Δt
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Centripetal Acceleration Acceleration toward the center of circular motion. Formula: a = v²/r
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Gravitational Acceleration Acceleration due to gravity. On Earth's surface: g ≈ 9.80665 m/s²
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Proper Acceleration Physical acceleration experienced by an object, measured by accelerometers
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Coordinate Acceleration Rate of change of coordinate velocity in a chosen reference frame
Key Acceleration Formulas
Understanding these fundamental formulas is essential for physics, engineering, and aerospace applications.
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Basic Definition a = Δv / Δt = (v₂ - v₁) / (t₂ - t₁)
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Newton's Second Law a = F / m (acceleration = force ÷ mass)
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Kinematic Equation v² = u² + 2as (final velocity squared)
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Free Fall s = ½gt² (distance fallen under gravity)
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Centripetal a = v²/r = ω²r (circular motion)
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Gravitational g = GM/r² (universal gravitation)
Understanding Acceleration Units
Acceleration units span multiple measurement systems used worldwide. The SI unit is meter per second squared (m/s²), but engineers, pilots, and scientists use various other units depending on their field.
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SI Units (m/s²) The international standard. Used in physics, engineering, and scientific research worldwide.
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Imperial Units (ft/s²) Used in US aerospace, automotive, and civil engineering. 1 ft/s² = 0.3048 m/s²
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g-force (g₀) Standard gravity = 9.80665 m/s². Used in aviation, spaceflight, and biomechanics.
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Galileo (Gal) 1 Gal = 1 cm/s². Used in gravimetry to measure Earth's gravitational variations.
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Planetary Gravities Surface gravity of Moon, Mars, Jupiter, etc. Essential for space exploration.
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Speed-based (km/h/s) Common in automotive industry. 0-100 km/h in X seconds = acceleration in km/h/s.
Planetary Surface Gravities
Surface gravity varies across celestial bodies due to differences in mass and radius. These values are critical for space missions, planetary science, and understanding weight on other worlds.
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Earth (g₀) 9.80665 m/s² — Standard reference for all acceleration measurements
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Moon 1.625 m/s² (0.166g) — About 1/6th of Earth's gravity
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Mars 3.72076 m/s² (0.379g) — About 38% of Earth's gravity
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Jupiter 24.79 m/s² (2.528g) — Strongest of the planets
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Venus 8.87 m/s² (0.905g) — Very close to Earth's gravity
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Saturn 10.44 m/s² (1.065g) — Slightly stronger than Earth
Real-World Applications
Acceleration measurements are critical across numerous fields of science, engineering, and everyday life.
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Aerospace Engineering Rocket launches experience 3-4g. Fighter pilots endure up to 9g. Space shuttle: 3g max.
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Automotive Industry 0-100 km/h times, braking deceleration, crash testing (up to 60g in collisions).
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Seismology Earthquake measurements in g-force. Major quakes: 0.5-1.0g ground acceleration.
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Biomechanics Human tolerance: sustained 5g causes blackout. Brief: up to 46g (John Stapp record).
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Gravimetry Measuring Earth's gravity variations for geology, oil exploration, and geodesy.
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Consumer Electronics Smartphone accelerometers measure device orientation, steps, and motion.
Why Professionals Choose ASLI FORM
Built with precision engineering and premium design, our converter meets the demands of physicists, engineers, and scientists.
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Scientific Precision Results accurate to 10 significant digits using NIST and BIPM standards.
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Planetary Data Includes surface gravities for all major planets, Moon, and Pluto from NASA data.
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Instant Results Real-time conversion as you type — no buttons to click, no waiting.
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Frequently Asked Questions
Standard gravity (g₀) is defined as exactly 9.80665 m/s² by international agreement (CGPM, 1901). It represents the nominal acceleration due to Earth's gravity at sea level and 45° latitude. This value is used as a reference in physics, engineering, aviation, and metrology. One g-force equals 9.80665 m/s². Standard gravity is crucial for calibrating instruments, designing structures, and comparing measurements worldwide.
The galileo (symbol: Gal) is a unit of acceleration equal to 1 centimeter per second squared (1 cm/s² = 0.01 m/s²). Named after Galileo Galilei, it is commonly used in gravimetry to measure variations in Earth's gravitational field. Sub-units include:
- Milligalileo (mGal) = 0.001 Gal = 10⁻⁵ m/s² — used in geological surveys
- Microgalileo (μGal) = 10⁻⁶ Gal = 10⁻ m/s² — used in precision gravimetry
The conversion is straightforward using the standard gravity constant:
- g-force to m/s²: Multiply by 9.80665. Example: 2g = 2 × 9.80665 = 19.6133 m/s²
- m/s² to g-force: Divide by 9.80665. Example: 49.03325 m/s² = 49.03325 ÷ 9.80665 = 5g
Planetary surface gravities (from NASA data):
- Moon: 1.625 m/s² (0.166g) — About 1/6th of Earth
- Mercury: 3.7 m/s² (0.377g)
- Mars: 3.72076 m/s² (0.379g) — About 38% of Earth
- Venus: 8.87 m/s² (0.905g) — Very close to Earth
- Earth: 9.80665 m/s² (1g) — Reference standard
- Saturn: 10.44 m/s² (1.065g)
- Uranus: 8.69 m/s² (0.886g)
- Neptune: 11.15 m/s² (1.137g)
- Jupiter: 24.79 m/s² (2.528g) — Strongest planet
- Pluto: 0.62 m/s² (0.063g) — Very weak gravity
Linear acceleration is the rate of change of linear velocity along a path, measured in m/s². It describes how fast an object speeds up or slows down in a straight line. Formula: a = Δv / Δt.
Angular acceleration is the rate of change of angular velocity, measured in radians per second squared (rad/s²). It describes how fast a rotating object changes its rotational speed. Formula: α = Δω / Δt.
The two are related by: a = α × r where r is the radius from the axis of rotation.
Angular acceleration is the rate of change of angular velocity, measured in radians per second squared (rad/s²). It describes how fast a rotating object changes its rotational speed. Formula: α = Δω / Δt.
The two are related by: a = α × r where r is the radius from the axis of rotation.
Human tolerance to g-force depends on duration, direction, and individual fitness:
- Sustained (minutes): 4-5g causes loss of consciousness (G-LOC)
- Brief (seconds): Up to 9g with G-suit (fighter pilots)
- Very brief (milliseconds): Up to 46g (John Stapp's 1954 rocket sled record)
- Negative g (headward): Only -2 to -3g tolerable (causes "redout")
- Lateral g: Higher tolerance, up to 15-20g briefly
Yes. Our converter uses internationally-recognized conversion factors from:
- NIST (National Institute of Standards and Technology)
- BIPM (International Bureau of Weights and Measures)
- IAG (International Association of Geodesy)
- NASA planetary data
Centripetal acceleration is the acceleration directed toward the center of a circular path that keeps an object moving in that circle. It is calculated using:
- a = v²/r (where v is linear velocity, r is radius)
- a = ω²r (where ω is angular velocity in rad/s)
Acceleration is measured using various instruments:
- Accelerometers: MEMS sensors in smartphones, cars, aircraft
- Piezoelectric sensors: For high-frequency vibration measurement
- Pendulum gravimeters: For precise gravity measurements
- Superconducting gravimeters: For microgal-level precision
- Atom interferometers: Cutting-edge quantum gravity sensors
- Strain gauges: For structural acceleration monitoring
This relationship is defined by Newton's Second Law of Motion:
F = m × a (Force = mass × acceleration)
Rearranged for acceleration: a = F / m
This means:
F = m × a (Force = mass × acceleration)
Rearranged for acceleration: a = F / m
This means:
- For a given force, greater mass results in less acceleration
- For a given mass, greater force results in more acceleration
- 1 Newton of force accelerates 1 kg of mass at 1 m/s²
This converter focuses on linear acceleration units. For angular acceleration, you would use units like rad/s², rev/s², or deg/s². These can be found in our dedicated Unit Converter tool under the "Angle" category combined with time units. Angular acceleration relates to linear acceleration by: a = α × r where α is angular acceleration and r is the radius.
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