Post Hole Concrete Calculator
This post hole concrete calculator computes the concrete needed to set fence posts, mailbox posts and deck supports. It subtracts the volume displaced by the post itself, so a concrete calculator with post dimensions gives a truer bag count than a plain cylinder.
كيفية استخدام هذه الحاسبة
- أدخل أبعادك — أقدام للأطوال، بوصات للسماكة.
- اضبط الخيارات — نسبة الهدر وحجم الكيس وسعر الخرسانة المحلي.
- اقرأ نتائجك — يتم تحديث الحجم والأكياس والوزن والتكلفة مباشرة أثناء الكتابة.
الصيغة
Volume per hole = π × (hole diameter ÷ 2)² × depth − post cross-section × depth مثال محلول: A 12 in hole, 24 in deep with a 4×4 post (3.5 in actual): π × 0.5² × 2 = 1.57 ft³ minus the post's 0.17 ft³ ≈ 1.40 ft³ — about 3 × 80 lb bags per hole.
The rule of thumb for any concrete calculator for post holes: hole diameter should be 3× the post width, and hole depth should be 1/3 to 1/2 of the post's above-ground height, always below frost depth.
For a standard fence — 4×4 posts in 12 inch holes, 24 inches deep — plan on roughly 3 × 80 lb bags (or 4 × 60 lb bags) per hole. Multiply by your post count above and the calculator totals everything, including a waste allowance.
Setting posts is the classic dry pour use-case: many installers pour the mix dry into the hole around the post and add water. For structural posts, mixed-and-placed concrete compacts better and reaches full strength more reliably.
الأسئلة الشائعة
أسئلة شائعة حول post hole concrete calculator.
How many bags of concrete per fence post?
For a 12 in hole 24 in deep around a 4×4 post: about 3 × 80 lb bags or 4 × 60 lb bags. Bigger holes scale fast — a 16 in hole needs nearly double.
How deep should a post hole be?
1/3 of the post height above ground (minimum 24 inches for a 6 ft fence), and always below the frost line in cold climates.
Does the calculator subtract the post volume?
Yes — enter your post width and the displaced volume is removed from each hole. Enter 0 to calculate a solid-filled hole.
Can I pour dry concrete into a post hole?
For fence posts, yes — pour dry mix and add water per bag directions. For decks or structural posts, pre-mix for full, uniform strength.
حاسبات ذات صلة
المزيد من الأدوات من عائلة حاسبات الخرسانة.