Patio Calculator: Pavers, Concrete or Gravel
Use this patio calculator to estimate all materials for outdoor patios, terraces, and garden walkways. Routes seamlessly between interlocking pavers, poured concrete slabs, pea gravel, and natural flagstone with complete sub-base compaction and drainage slope guidance.
Order 939 pavers + 7 tons crushed base + 1.30 tons sand + 4 bags polymeric sand + 10 edge strips.
| Patio Surface Area | 320 sq ft |
|---|---|
| Paver Dimensions | 6" × 9" Holland Stone |
| Total Pavers with 10% Waste | 939 pavers |
| Compacted Road Base (4") | 7.0 tons (4.0 cu yds) |
| Coarse Bedding Sand (1" depth) | 1.3 tons concrete sand |
| Polymeric Joint Sand (50-lb) | 4 bags |
| Snap-Edge Restraints & Spikes | 10 pieces of 6-ft edging (40 spikes) |
How to Measure for Patio Calculator
- Measure patio length and width in feet, or divide freeform curved patios into rectangular sections.
- Choose your surface paving material: Interlocking concrete pavers, poured ready-mix concrete slab (4" thick), bulk pea gravel, or flagstone.
- Determine sub-base excavation depth: standard pedestrian patios require 4" to 6" of compacted crushed road base (crusher run) plus a 1" bedding sand layer.
- Plan a 1/4" per foot drainage slope away from home foundation walls (1 inch drop every 4 feet of patio run).
How the Calculation Works
Material requirements depend on the selected surface material. For pavers: `Total Pavers = Ceil((Patio Sq Ft / Single Paver Sq Ft) × 1.10 Waste)`. Crushed stone road base (4" compacted depth) is computed as: `Tons = (Area × 0.333 ft / 27) × 1.6 tons/yd³ × 1.10 Compaction`. Bedding sand (1" uncompacted depth) uses: `Tons = (Area × 0.0833 ft / 27) × 1.35 tons/yd³`. Edge restraints equal the exposed perimeter footage. Polymeric joint sand is estimated at 1 bag (50-lb) per 75–100 sq ft.
- Pavers needed = ceil((320 / 0.375) × 1.10) = ceil(853.3 × 1.10) = 939 pavers (~3 pallets of 300). Base gravel volume = (320 × 0.333) / 27 = 3.95 cu yds × 1.6 tons/yd × 1.10 compaction = 6.95 tons (order 7.0 tons). Bedding sand = (320 × 0.0833) / 27 = 0.987 cu yds × 1.35 tons/yd = 1.33 tons. Edge restraint = 56 linear feet (~9 pieces of 6-ft plastic edging + 36 spikes). Polymeric sand = ceil(320 / 80) = 4 bags (50-lb).
Patio Calculator Reference & Specifications
| Patio Material Option | Excavation Depth | Sub-Base Layers Required | Lifespan & Maintenance |
|---|---|---|---|
| Interlocking Concrete Pavers | 7" to 9" total excavation | 4"–6" Crushed stone base + 1" coarse sand | 30+ years (easy to lift & repair) |
| Poured Concrete Slab (4") | 8" total excavation | 4" Compacted gravel + 4" 4,000 psi concrete | 25+ years (requires control joints) |
| Crushed Gravel / Pea Gravel | 5" to 6" total excavation | 3"–4" Road base + landscape fabric + 2" top stone | 10–15 years (periodic raking / topping) |
| Natural Flagstone (Dry Laid) | 8" to 10" total excavation | 4"–6" Crushed base + 1"–2" stone dust / sand | 40+ years (natural organic aesthetic) |
Frequently Asked Questions About Patio Calculator
How thick should a patio base be for pavers?
For standard pedestrian patio traffic (foot traffic, outdoor dining furniture, and grills), a 4-inch compacted layer of crushed road base (Class 5 or crusher run) is the universal standard. For driveways or heavy hot tubs, increase the compacted base to 8 to 10 inches.
How much slope does a backyard patio need for water drainage?
Patios should slope away from house foundations at a rate of 1/4 inch per linear foot (a 1-inch vertical drop for every 4 feet of horizontal distance, or about a 2% slope). This ensures heavy rain drains away quickly without pooling or seeping into the basement.
What type of sand should be used for bedding pavers?
Always use coarse, angular concrete sand (ASTM C33 specification). Never use fine playground sand, mason sand, or stone dust for the 1-inch bedding layer, as fine sands hold moisture, wash out easily, and prevent proper drainage.
How many bags of polymeric sand do I need for my patio?
One standard 50-pound bag of polymeric joint sand covers approximately 60 to 85 square feet of standard pavers with narrow 1/8" joints. For wide joint flagstone (1/2" to 1" joints), coverage drops to 20 to 35 square feet per bag.
Why are plastic or aluminum edge restraints essential?
Without rigid edge restraints nailed down into the crushed gravel base with 10-inch steel spikes, lateral pressure from foot traffic and winter freeze-thaw cycles will push perimeter pavers outward, causing joints to open and pavers to sink.