# 加速度変換

> Convert g-force to m/s², m/s² to g, ft/s² and gal (cm/s²), using standard gravity g₀ = 9.80665 m/s² exactly.

操作できるページ：https://www.calcopenly.com/ja/conversion/acceleration-converter
分野：単位換算ツール

Acceleration is change of speed per unit time, and each unit here is a fixed number of metres per second squared. The g of g-force is standard gravity, g₀ = 9.80665 m/s², fixed by the 3rd CGPM in 1901; a foot per second squared is 0.3048 m/s², and a gal (galileo) is 1 cm/s².

The default converts 1 g to 9.80665 m/s². Vehicle performance is the everyday use: a car that reaches 100 km/h from rest in 3 seconds averages 9.26 m/s², or 0.94 g.

Standard gravity is a conventional value. Real free-fall acceleration runs from about 9.78 m/s² at the equator to 9.83 m/s² at the poles, and geophysicists measure its local variations in milligals.

## 入力

- **値**: 変換元の単位で数値を入力するか、単位付きの数値を入力します
- **変換元** (選択肢：metre per second squared (m/s²), standard gravity (g), foot per second squared (ft/s²), gal (galileo))
- **変換先** (選択肢：metre per second squared (m/s²), standard gravity (g), foot per second squared (ft/s²), gal (galileo))

## 結果

- 変換後の値 — 主な結果
- 単位換算
- 換算係数
- 正確さ

## 計算式

$$
\begin{gathered} x_{\text{to}} = x_{\text{from}} \times \dfrac{f_{\text{from}}}{f_{\text{to}}} \\ f = \text{one unit expressed in } \text{m/s²} \end{gathered}
$$

## 計算例

### 1 g in m/s²

- 値: 1 g
- 変換元: standard gravity (g)
- 変換先: metre per second squared (m/s²)
- **変換後の値: 9.80665 m/s²**
- 照合元：Standard gravity g₀ = 9.80665 m/s² exactly (CGPM 1901)

### 1 g in ft/s²

- 値: 1 g
- 変換元: standard gravity (g)
- 変換先: foot per second squared (ft/s²)
- **変換後の値: 32.1740485564 ft/s²**
- 照合元：9.80665 / 0.3048 = 196133/6096 (Python 3.8 fractions from the legal definitions)

### 1 gal in m/s²

- 値: 1 Gal
- 変換元: gal (galileo)
- 変換先: metre per second squared (m/s²)
- **変換後の値: 0.01 m/s²**
- 照合元：1 Gal = 1 cm/s² (NIST SP 811 App. B)

### 9.80665 m/s² is exactly 1 g

- 値: 9.80665 m/s²
- 変換元: metre per second squared (m/s²)
- 変換先: standard gravity (g)
- **変換後の値: 1 g**
- **正確さ: 正確**
- 照合元：Definition of g₀

## よくある質問

### What is 1 g in m/s²?

Exactly 9.80665 m/s², the standard acceleration of gravity adopted by the 3rd General Conference on Weights and Measures in 1901. It equals 32.174 ft/s². Local gravity differs slightly; 9.80665 is the convention used for g-force and for units such as the kilogram-force.

### How do I work out g-force from a 0–60 or 0–100 time?

Divide the speed gained by the time, then divide by 9.80665. 0–60 mph (26.8224 m/s) in 3 s averages 8.94 m/s², or 0.91 g; 0–100 km/h (27.78 m/s) in 3 s averages 9.26 m/s², or 0.94 g. The peak acceleration during the run is higher than this average.

### What is a gal (Gal) in acceleration?

One centimetre per second squared, 0.01 m/s², named after Galileo. Earth's surface gravity is about 980 Gal, so gravity surveys work in milligals, where 1 mGal is about one millionth of g. The symbol is Gal, and the unit has nothing to do with the gallon.

### How do I convert ft/s² to m/s²?

Multiply by 0.3048, the exact number of metres in a foot. 32.174 ft/s² is 9.80665 m/s² (1 g), and 10 ft/s² is 3.048 m/s². To go from m/s² to ft/s², divide by 0.3048, which is the same as multiplying by 3.28084.

### Is gravity 9.81 m/s² everywhere?

No. Free-fall acceleration is about 9.780 m/s² at the equator and 9.832 m/s² at the poles, because the Earth spins and bulges at the equator, and it falls slightly with altitude. 9.81 is 9.80665 rounded, the conventional value between those extremes that g-force is measured against.

### 「加速度変換」の精度はどのくらいですか？

精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：4。 例えば、「1 g in m/s²」はStandard gravity g₀ = 9.80665 m/s² exactly (CGPM 1901)と照合しています。

### この計算方法の出典は何ですか？

NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors; NIST Handbook 44, Appendix C — General tables of units of measurement.

## 出典

- [NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C — General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)