Post Hole Concrete Worksheet: Mixed Groups

A fence or post project can contain several concrete quantities even when every hole sits on one site. Line posts, corners, ends, gate posts, sign posts, and repairs may use different approved geometry, post sections, concrete depths, or placement stages.

A quantity worksheet keeps those differences visible. Calculate each repeated group from its own dimensions, preserve the unrounded net volume, then combine only the groups that share one product, allowance basis, and workable placement plan.

How do you build a post-hole concrete quantity worksheet?

Create one row for every group of identical holes. Record the concrete boundary, post displacement, count, net group volume, allowance, product yield, and package quotient in separate columns.

Use the Concrete Post Hole Calculator to calculate each straight round, tapered round, or rectangular group. Copy its unrounded result into the worksheet before package groups are formed.

Download the blank CSV worksheet

Which columns belong in the worksheet?

Units belong in the header or every row. Do not mix inches with feet or millimetres with metres without an explicit conversion.

When should holes be split into separate groups?

Start a new group whenever a geometry, post, product, allowance, approval, or work-stage input changes. Identical location names do not prove identical quantities.

• A gate hinge post and latch post use different approved details.
• Corner holes have another diameter or widened bottom.
• One line-post run has a different concrete depth because the approved detail changes.
• A repair hole contains accepted overbreak or old-concrete removal.
• Steel and timber posts occupy different cross-sections.
• Several groups use different packaged products or yields.
• Separate days or hold points prevent fresh concrete from being shared.

The Chain Link Fence Manufacturers Institute installation guide distinguishes line and terminal posts in its fence-layout terminology. That source supports the need to identify post roles. It does not supply one concrete geometry for every system or site.

What formulas does the worksheet use?

Straight round hole = π × (diameter ÷ 2)² × concrete fill depth

Tapered round hole = π × depth ÷ 12 × (top diameter² + top diameter × bottom diameter + bottom diameter²)

Round post displacement = π × (post diameter ÷ 2)² × post depth in concrete

Rectangular post displacement = post length × post width × post depth in concrete

Group net volume = (gross per hole − displacement per hole) × hole count

Planning volume = group net volume × (1 + allowance % ÷ 100)

Whole packages = ceiling(compatible planning volume ÷ current mixed yield)

Use the Concrete Post Hole Volume guide for vertical zones, post overlap, tapered holes, square holes, and field overbreak. The Concrete Bags per Post Hole Chart gives quick straight-hole reference rows.

Worked worksheet: line, corner, and gate groups

This arithmetic fixture contains 18 holes. Its dimensions demonstrate the schedule and do not prescribe a fence detail.

Each row uses full-precision geometry before the displayed value is rounded. A separate check reproduces every row from the stated dimensions.

How is the line-post row calculated?

The line group uses straight cylinders and measured round-post displacement:

1. Gross per hole: π × (10 ÷ 2)² × 24 ÷ 1,728 = 1.090831 ft³.
2. Post displacement per hole: π × (2.375 ÷ 2)² × 22 ÷ 1,728 = 0.056403 ft³.
3. Net per hole: 1.090831 − 0.056403 = 1.034429 ft³.
4. Group net: 1.034429 × 12 = 12.413143 ft³.

Keep the 12.4131429779 ft³ source value in the worksheet. Display rounding should not change the later package result.

How is the tapered corner row calculated?

The corner fixture uses a circular frustum because the bottom diameter differs from the top:

1. Gross per hole: π × 30 × (12² + 12 × 14 + 14²) ÷ (12 × 1,728) = 2.308925 ft³.
2. Post displacement per hole: π × (2.875 ÷ 2)² × 27 ÷ 1,728 = 0.101434 ft³.
3. Net per hole: 2.308925 − 0.101434 = 2.207491 ft³.
4. Group net: 2.207491 × 4 = 8.829963 ft³.

Use this formula only when a frustum represents the accepted concrete boundary. A bell, step, collapse, leaning bore, or local widening needs separate measured sections.

How are compatible groups converted to bags?

Assume the 3 groups use one approved product, one 5% allowance basis, and one compatible placement plan. The current product record states 0.60 ft³ of approximate mixed yield per package.

1. Total measured volume: 12.413143 + 8.829963 + 5.960381 = 27.203487 ft³.
2. Planning volume: 27.203487 × 1.05 = 28.563661 ft³.
3. Exact package quotient: 28.563661 ÷ 0.60 = 47.606102.
4. Whole-package result: 48 packages.
5. Purchased mixed capacity: 48 × 0.60 = 28.8 ft³.
6. Capacity above planning quantity: 28.8 − 28.563661 = 0.236339 ft³.

The 5% allowance is a fixture input. Enter 0% until project evidence supports another value. Use the Concrete Bag Yield Chart to verify the exact product and current package yield.

What changes when the groups cannot share one placement?

Calculate separate package ceilings when product, allowance, work date, hold point, acceptance record, or placement logistics prevent concrete from being shared.

Separate ceilings add 1 package in this fixture. The Concrete Bag Rounding guide explains product, working-time, storage, and placement-group boundaries.

How should field changes be recorded?

Keep the original row and add a dated revision or change line. Record the affected hole IDs, original geometry, accepted changed geometry, volume difference, reason, approval, and effect on the placement group.

A project-wide percentage cannot show which hole changed or whether its accepted foundation still matches the design. Use Oversized Post Hole Concrete to calculate a wider or locally changed boundary as a separate quantity.

Can the worksheet decide which posts need larger holes?

The worksheet records approved differences. It does not decide them.

Gate loads, fence tension, wind, post material, height, soil, frost, corrosion, drainage, spacing, bracing, connections, hardware, vehicle impact, and local requirements can change the detail. Use the current drawings, product system, permit, code, and responsible design process.

Forum comments and simplified calculators often assign fixed bags to line or gate posts. Those statements can reveal the question people ask, but they cannot approve geometry or concrete quantity for another project.

How should packaged concrete and ready mix stay separate?

Package planning divides compatible volume by the exact product's mixed yield. Ready-mix planning uses the checked volume, supplier selling increment, mixture requirements, delivery, access, placement rate, and current commercial terms.

Use the Ready-Mix Concrete Calculator when a producer will supply the concrete. Keep the measured worksheet total available so package and supplier comparisons start from the same approved geometry.

How should the worksheet be checked?

1. Compare every row with the current drawing, detail, permit, or accepted field record.
2. Check units and vertical limits before recalculating geometry.
3. Reproduce gross volume and displacement independently.
4. Confirm hole count against the layout and field IDs.
5. Add unrounded group volumes and compare the total.
6. Verify allowance, product, package, market, and yield sources.
7. Check compatible placement groups before applying whole-package ceilings.
8. Confirm supplier increments, stock, transport, and handling separately.
9. Record preparer, checker, date, revision, and unresolved conditions.

Common post-hole worksheet mistakes

• Using one row for line, corner, end, and gate holes that have different inputs.
• Copying a post-type label without the approved geometry.
• Using total excavation depth as concrete fill depth.
• Subtracting the post through concrete below the post bottom.
• Applying a cylinder to a tapered or damaged hole.
• Rounding every hole before compatible volumes are combined.
• Combining different products or yields.
• Adding a default allowance without a source.
• Replacing a field change with a project-wide buffer.
• Using package mass as mixed yield.
• Letting a spreadsheet total hide an unresolved safety or design condition.

Return to the Concrete Planning hub for related quantity tools and guides.

What safety and scope limits apply?

Locate expected underground utilities before excavation. OSHA 29 CFR 1926.651 sets this requirement for covered United States construction work and requires safe location steps as excavation approaches an installation.

Wet portland cement can cause caustic burns and dermatitis. Follow the current product safety data sheet and applicable controls for skin, eyes, dust, lifting, mixing equipment, water, and washing facilities.

A worksheet cannot approve excavation, ground conditions, temporary support, equipment, access, post stability, concrete selection, placement, or completed work. Stop the quantity handoff when geometry, approval, utility location, product, field condition, or safety control remains unresolved.