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The whole fence order — posts to concrete — in one pass.
Fence material lists follow repeatable rules: a post every 8 feet plus a starter, doubled posts at every gate, two or three rails per section depending on height, and boards counted by coverage width. Getting any of these wrong means a mid-job supplier run. This calculator applies the standard counts and adds concrete at two 50-lb bags per post, so your order matches the plan.
DIYers pricing a backyard fence and fencing contractors building a first-pass estimate both use this: posts, rails, boards, and concrete all follow simple count rules, but the gate subtraction and doubled gate posts are where orders go wrong. The cost layer doubles as a homeowner's check against a fencing quote.
At 8-foot sections: ⌈100 ÷ 8⌉ + 1 = 14 posts for the fence line, plus 2 extra per gate (gate posts carry the load and are typically doubled or upsized). A 100-ft line with one 4-ft gate needs 15 posts and leaves 96 ft of actual fencing.
Two 50-lb bags for a standard 4×4 post in an 8-inch-diameter hole set 24 inches deep (the hole holds about 0.7 cubic feet). Frost-line depths deeper than 24" or 6×6 gate posts need more — check your local frost depth before digging.