selector {
    table-layout: auto | fixed
    /*  auto  : 자동 방식
        fixed : 고정 방식 */
}
/* 키워드 값 */
table-layout: auto;
table-layout: fixed;

/* 전역 값 */
table-layout: inherit;
table-layout: initial;
table-layout: revert;
table-layout: revert-layer;
table-layout: unset;
CSS 데모: table-layout 데모 버튼을 클릭해 보세요!
<table class="auto-table-layout">
    <caption>auto</caption>
    <tr>
        <th scope="col">이름</th>
        <th scope="col">국가</th>
    </tr>
    <tr>
        <td>홍길동</td>
        <td>대한민국</td>
    </tr>
    <tr>
        <td>Sir Tim Berners-Lee</td>
        <td>영국</td>
    </tr>
    <tr>
        <td>Albert Einstein</td>
        <td>독일</td>
    </tr>
</table>
<table class="fixed-table-layout">
    <caption>fixed</caption>
    <tr>
        <th scope="col">이름</th>
        <th scope="col">국가</th>
    </tr>
    <tr>
        <td>홍길동</td>
        <td>대한민국</td>
    </tr>
    <tr>
        <td>Sir Tim Berners-Lee</td>
        <td>영국</td>
    </tr>
    <tr>
        <td>Albert Einstein</td>
        <td>독일</td>
    </tr>
</table>
.auto-table-layout {
    table-layout: auto;
}
.fixed-table-layout {
    table-layout: fixed;
}

table {
    display: inline-table;
    width: 130px;
    border-collapse: collapse;
    margin: 1em;
}
th, td {
    border: 1px solid;
    padding: 0.4em 1em;
    text-align: center;
}
th {
    background-color: #e6e6e6;
}
실제 적용된 모습