以下详细说明暂以英文提供。
How the post count works
A straight run divides its length by the post spacing, rounds up to whole intervals, then adds one post to close the far end — a 100-foot fence on 8-foot spacing needs thirteen intervals and therefore fourteen posts. Every gate adds one more post because a gate needs a hinge side and a latch side. Corners and direction changes each want a braced post too, so L-shaped runs cost more posts than the straight-line math suggests.
Two rails or three?
Two rails carry most privacy and wood picket fences comfortably on 6–8 foot spacing. Three rails earn their keep on taller fences, wide post spacing, stock panels, or anywhere animals (or large dogs) lean on the fence — the middle rail stops boards from bowing between posts. Rail length multiplies the full run, so three rails on a 100-foot fence means 300 linear feet of material to buy.
中国本地参考
日常计算时值得知道的中国本地规则：
- 计量的单位习惯: 住房面积用平方米，土地常用亩（1 亩 ≈ 666.7 平方米）；里程用公里，油耗用 L/100km。
- 日期与数字格式: 日期写作 2026年10月13日（年-月-日）；大数习惯用万、亿（1 万 = 10,000，1 亿 = 100,000,000）。
- 法定节假日: 全年法定节假日 11 天，春节与国庆为长假；调休安排每年由国务院办公厅发布。
- 速度与限速: 高速公路最高限速 120 km/h，城市快速路多为 80 km/h，均以公里每小时计。
- 鞋服尺码: 鞋码用中国码（毫米制），服装常用 155/80A 这类身高围度组合，与欧美码不同。
数据核对：2026 年 10 月
常见问题
What post spacing should I use?
Six to eight feet is standard for wood and vinyl; check your fence panel width first, because panels that span post to post lock you into their length. Windy, exposed sites often tighten spacing to six feet.
Do gates change the rail length?
A gate replaces a span of rail rather than extending the fence, so this calculator keeps rail length at the full run — you will buy slightly more rail than strictly needed, which covers the frame lumber gates consume anyway.
Are corner and end posts included?
The two ends of the run are included by the plus-one rule. Each corner or turn adds one more post that the straight-line count cannot see — add them mentally for L- or U-shaped layouts.