# G-Force Calculator

Calculate g-force from velocity change and time or from turn radius and speed. Find acceleration in g's, m/s², and force on the human body.

## What this calculates

G-force measures acceleration as a multiple of Earth's gravitational acceleration (1g = 9.81 m/s²). Standing still, you experience 1g. A roller coaster might hit 3-4g in a tight loop, fighter pilots experience up to 9g in hard turns, and a car crash can produce 50g or more in milliseconds. This calculator works for both straight-line acceleration/deceleration and circular motion.

## Inputs

- **Calculation Mode** — options: Linear (velocity change & time), Circular (radius & speed)
- **Velocity Change** (m/s) — min 0 — For linear mode: total velocity change (delta-v).
- **Time Duration** (s) — min 0 — Time over which the velocity change occurs.
- **Turn Radius** (m) — min 0 — For circular mode: radius of the curved path.
- **Speed** (m/s) — min 0 — For circular mode: speed through the turn.

## Outputs

- **G-Force** (g) — Acceleration as a multiple of Earth's gravity (9.80665 m/s²)
- **Acceleration** (m/s²) — Acceleration in meters per second squared
- **Force per kg of Mass** (N) — Force experienced per kilogram of body mass
- **Force on 80 kg Person** (N) — Total force on an average 80 kg (176 lb) person

## Details

G-force is calculated two ways depending on the situation:

Linear acceleration:

g-force = (delta-v / time) / 9.80665

A car going from 0 to 60 mph (26.8 m/s) in 3 seconds pulls about 0.91g.

Circular motion:

g-force = v² / (r x 9.80665)

A car doing 30 m/s through a 50 m radius turn pulls about 1.84g laterally.

What different g-forces feel like:

  - 1g: Normal gravity, standing on Earth

  - 2g: Moderate roller coaster, hard turn in a sports car

  - 3-4g: Intense roller coaster, aerobatic flying

  - 5-6g: Onset of tunnel vision for untrained people

  - 7-9g: Fighter pilot territory, requires g-suit and training

  - 10g+: Sustained exposure causes blackout; brief exposure survivable in crashes

  - 0g: Weightlessness (free fall, space station orbit)

## Frequently Asked Questions

**Q: What is 1g of force?**

A: 1g equals the acceleration due to Earth's gravity: 9.80665 m/s² (32.174 ft/s²). When you stand on a scale, you experience 1g. It is not actually a force, but an acceleration. The force on your body at 1g equals your weight. At 2g, the force is twice your weight.

**Q: How many g's can a human survive?**

A: Duration matters enormously. Trained fighter pilots can sustain 9g for a few seconds with a g-suit. In car crashes, people have survived brief peaks of 40-80g when properly restrained. Colonel John Stapp survived 46.2g for a fraction of a second on a rocket sled in 1954. Sustained exposure above about 5g causes blood pooling and loss of consciousness.

**Q: Why do astronauts experience 0g in orbit?**

A: Astronauts in orbit are in continuous free fall around the Earth. The spacecraft and everything inside it are falling toward Earth at the same rate, so there is no relative acceleration between the astronaut and the ship. They still feel gravity (it is only about 10% weaker at ISS altitude), but since everything falls together, there is no contact force and they feel weightless.

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Source: https://vastcalc.com/calculators/physics/g-force
Category: Physics
Last updated: 2026-04-08