Convert UK gallon to US oil barrel
Unit definitions
UK gallon
The UK gallon is a unit of volume equal to exactly $4.546\,09$ liters.
US oil barrel
The US oil barrel is defined as exactly $42$ US liquid gallons. It is used for measuring crude oil and other petroleum products.
How to convert UK gallon to US oil barrel
$$\text{Volume}_{\text{bbl (oil)}} = \text{Volume}_{\text{gal (uk)}} \cdot 0.02859404584535368880177164844352851$$
Examples
Example 1
Convert $30.0\ \text{gal (uk)}$ to $\text{bbl (oil)}$.
$$\text{Volume}_{\text{bbl (oil)}} = 30.0 \cdot 0.02859404584535368880177164844352851$$
$$\text{Volume}_{\text{bbl (oil)}} = 0.857821$$
$$\therefore \ 30.0\ \text{gal (uk)} = 0.857821 \ \text{bbl (oil)}$$
Example 2
Convert $85.0\ \text{gal (uk)}$ to $\text{bbl (oil)}$.
$$\text{Volume}_{\text{bbl (oil)}} = 85.0 \cdot 0.02859404584535368880177164844352851$$
$$\text{Volume}_{\text{bbl (oil)}} = 2.430494$$
$$\therefore \ 85.0\ \text{gal (uk)} = 2.430494 \ \text{bbl (oil)}$$
Example 3
Convert $120.0\ \text{gal (uk)}$ to $\text{bbl (oil)}$.
$$\text{Volume}_{\text{bbl (oil)}} = 120.0 \cdot 0.02859404584535368880177164844352851$$
$$\text{Volume}_{\text{bbl (oil)}} = 3.431286$$
$$\therefore \ 120.0\ \text{gal (uk)} = 3.431286 \ \text{bbl (oil)}$$
Example 4
Convert $135.0\ \text{gal (uk)}$ to $\text{bbl (oil)}$.
$$\text{Volume}_{\text{bbl (oil)}} = 135.0 \cdot 0.02859404584535368880177164844352851$$
$$\text{Volume}_{\text{bbl (oil)}} = 3.860196$$
$$\therefore \ 135.0\ \text{gal (uk)} = 3.860196 \ \text{bbl (oil)}$$
Example 5
Convert $195.0\ \text{gal (uk)}$ to $\text{bbl (oil)}$.
$$\text{Volume}_{\text{bbl (oil)}} = 195.0 \cdot 0.02859404584535368880177164844352851$$
$$\text{Volume}_{\text{bbl (oil)}} = 5.575839$$
$$\therefore \ 195.0\ \text{gal (uk)} = 5.575839 \ \text{bbl (oil)}$$