Patio Base Calculator
The ICPI section: excavation depth, base × 1.25 compaction at 1.40 t/yd³, one inch of bedding sand at 1.35, edge restraint, polymeric — everything UNDER the pavers.
Patio Base Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Rectangular sections — curves order by segments.
- No geotextile or drainage sub-layer line.
- Tonnages assume dense-grade crush and C33 sand.
In short: A 12 × 16 patio (192 ft²): base 4 in → 2.3704 yd³ ×1.25 compaction = 2.9630 yd³ → 4.15 t of crushed stone at 1.40 t/yd³. Sand 1 in: 0.5926 yd³ ×1.25 ×1.35 t/yd³ = 1.00 ton EXACTLY. Edge: 56 lf, spikes every 12 in; polymeric sand: 4 bags at 50 ft² each.
Formula
base yd³ = ft² × in ÷ 324, × 1.25 compaction
base t = loose yd³ × 1.40; sand t = × 1.35
edge lf = 2 × (L + W); spikes every 12 in
polymeric bags = ⌈ft² ÷ 50⌉
[('1.25', 'the compaction order-up, always'), ('1.40 / 1.35', 't/yd³ for crush / sand'), ('1 in', 'bedding sand — ICPI, never > 1½'), ('50 ft²', 'polymeric per 50-lb bag, safe end')]
Worked Example
- Area × base in ÷ 324, × 1.25, × 1.40 → tons.
- Sand: × 1.25, × 1.35 → tons.
- Edge = perimeter; spikes every foot.
- Polymeric = area ÷ 50 per bag.
- Dig base+sand+paver deep; slope 2%.
192 ft², 4-in base: 2.3704 → 2.9630 yd³ → 4.15 t. Sand: 0.5926 → 0.7407 yd³ → 1.00 t. Edge 56 lf, 56 spikes, 4 polymeric bags, dig ~7.4 in.
Strengths & Limits Of This Model
Where this engine is strong
- Compaction multiplier on BOTH layers, not just one
- The sand lands on 1.00 ton — the math itself is the story
- Dig depth and slope carry through to the shovel
Where it stops
- No geotextile roll count
- Rectangles only
Practical Use Cases
Patio builds
The whole under-section ordered.
Walkways
Small areas, same law.
Driveway-on-paver plans
The 6-in base case.
Dump-run math
Tons by trunk trips.
Contractor checks
Their base depth vs ICPI.
Methodology & Editorial Standards
Base: ft² × in ÷ 324 × 1.25 compaction × 1.40 t/yd³. Sand: ft² × in ÷ 324 × 1.25 × 1.35. Edge = perimeter with 12-in spike count; polymeric = ceil(ft² ÷ 50). Excavation = base + sand + paver thickness. Zero sides, areas past 5,000 ft², base outside 3-12 in, sand past 1½ in, pavers outside 1½-4 in refused.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Patio Base Calculator — 8 Expert FAQs
8 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How much base do I need for a paver patio?
Area × inches ÷ 324 gives compacted yards; multiply by 1.25 for compaction and order in tons at 1.40 t/yd³ — 192 ft² at 4 in wants 2.96 loose yards, 4.15 tons.
How thick should paver base be?
ICPI: 4 in of compacted crushed stone for patios, 6 for driveways, 8-12 over soft clays. Skimping here is the rut you will re-level every spring.
Why order 25% more base than the volume?
Loose stone compacts about 25% — the truck delivers air between the rocks. Order compacted volume × 1.25 or the last third of the patio starves.
How much sand under pavers?
One inch of washed concrete sand (C33), screeded dry — never more than 1½. Thick sand feels forgiving and ruts like a beach; the base carries load, the sand only beds the pavers.
How much polymeric sand do I need?
A 50-lb bag does 50-75 ft² depending on joint width — plan 50. The 192-ft² patio here takes 4 bags, swept and misted to set.
Does edge restraint matter?
It is the frame that stops sand migration and the creep that opens joints — spike plastic edge every 12 in around the perimeter, 56 lf and 56 spikes on this patio.
Do I need geotextile under the base?
Over soft or clay soils, yes — the fabric keeps stone from punching into the subgrade and the subgrade from muddying the stone. It adds no tons; it lies under the excavation before the first yard drops.
Paver page or this page?
The Paver page counts stones by pattern; the Paver Sand page details the bedding. This page orders the SECTION: dig depth, stone tons, sand tons, edge and polymeric — everything beneath the pavers.