Paver Base Calculator
This free paver base calculator answers one question, cleanly: how much gravel base and bedding sand do you need. It skips the paver catalog, pattern, joint width, and edge restraint choices — if you already know those, the Paver Calculator gives you the full materials list in one pass. This tool is for the planning stage, or for ordering base material on a different schedule than the pavers themselves.
Base depth comes straight from ICPI Tech Spec 2 by application — a pedestrian patio needs less than a residential driveway, which needs less than a light-vehicular surface. It applies the standard 1.25× compaction factor so you order enough loose material to reach the compacted depth you need, adds a soft-soil allowance when your subgrade calls for it, and can size a geotextile fabric layer too. Pick permeable (PICP) instead of sand-set and it switches to the three-layer open-graded stone system — no sand anywhere — per Tech Spec 18.
Everything is grounded in ICPI/CMHA Tech Spec 2 and Tech Spec 18, using the same verified base and compaction figures already live on the Paver Calculator. Sizing only — no pricing, no signup.
Paver Base Calculator
How much gravel base and bedding sand do you need for a paver patio or driveway? Base depth, compaction, and bedding by application — before you've picked a paver. Free, no signup.
Area & application
Already picked pavers? The Paver Calculator gives you this plus paver count, joints, and edge restraint in one pass.
Base method
Sand-set is the standard method for most patios and driveways. PICP (permeable) uses open-graded stone with no sand, for stormwater infiltration.
Base depth by application (ICPI Tech Spec 2)
Minimum compacted aggregate base depth, before any soft-soil addition.
| Application | Min. base depth | Slope |
|---|---|---|
| Pedestrian patio / walkway | 4" | 1.5% |
| Residential driveway | 6" | 2% |
| Light vehicular (parking, alleys) | 10" | 2% |
Ready to pick pavers, a pattern, and joint sand? Use the Paver Calculator for the full materials list.
What's actually buried under a paver patio
A paver surface is mostly what you don't see — the compacted base and bedding sand this calculator sizes make up nearly all the depth. This cross-section shows how the layers stack, from compacted subgrade up to the pavers themselves.
Calculation Formulas
ICPI Tech Spec 2 sets a minimum compacted aggregate base depth by how the surface will be used — a pedestrian patio needs less base than a driveway carrying vehicle loads. Soft, wet, or cold-climate subgrade calls for extra depth above the minimum.
Example:
A residential driveway needs 6" of compacted base; a pedestrian patio needs 4".
The compacted base extends 6 inches past the paved surface on every side, so edge restraint spikes anchor into compacted aggregate rather than native soil.
Example:
A 20×15 ft patio needs a 21×16 ft base footprint.
Aggregate compacts by roughly 20-25% when placed and rolled. Order enough loose material to end up with the compacted depth you need after compaction — this calculator applies that factor automatically.
Example:
A 4" compacted base over 350 sq ft needs about 30% more loose material by volume than the finished depth alone suggests.
Permeable interlocking concrete pavement (PICP) uses no sand anywhere in the system — three progressively finer open-graded stone layers let water pass through to the subgrade. Subbase depth varies by pedestrian vs. vehicular use; base and bedding depths are fixed.
Example:
A pedestrian PICP patio needs 8" of No. 2 subbase, 4" of No. 57 base, and 2" of No. 8 bedding.
On fine-grained or moist subgrade, a geotextile separation fabric (AASHTO M-288) keeps the base from mixing into the soil over time. Sold in rolls — a common commercial size is used here, but roll dimensions vary by supplier.
Example:
A 336 sq ft base footprint needs about 1 roll of 12.5×300 ft fabric.
Standard Constants
| Constant | Value | Description |
|---|---|---|
| Pedestrian patio base | 4" minimum | ICPI Tech Spec 2 minimum compacted aggregate base for foot-traffic-only surfaces. |
| Residential driveway base | 6" minimum | ICPI Tech Spec 2 minimum for passenger-vehicle driveways. |
| Light vehicular base | 10" minimum | ICPI Tech Spec 2 minimum for parking areas and alleys carrying occasional heavier loads. |
| Bedding sand depth | 1" (screeded, not compacted) | Tech Spec 2 — a uniform 1-inch layer of concrete sand the pavers are set into. Never used to correct a low or uneven base. |
| Compaction factor | 1.25× loose-to-compacted | The multiplier applied to compacted volume to determine how much loose material to order. |
| PICP layer depths | No.2: 8"/12" · No.57: 4" · No.8: 2" | Tech Spec 18 — subbase depth depends on pedestrian vs. vehicular use; base and bedding depths are fixed regardless of use. |
| Compaction standard | 98% Standard Proctor (ASTM D698) | The density target for compacting the aggregate base in 2-4 inch lifts before placing bedding sand. |
Note: All calculations include appropriate waste factors based on project complexity and material type. Results are estimates and should be verified by professionals before purchasing materials.
ICPI/CMHA Tech Spec 2 — Structural Design of Interlocking Concrete Pavement(ICPI/CMHA Tech Spec 2)
View StandardSets minimum aggregate base depths and bedding sand specifications for sand-set segmental pavement by application (pedestrian, residential driveway, light vehicular).
Key Requirements:
- •Minimum base depth by application (4"/6"/10")
- •1" screeded bedding sand, ASTM C33 concrete sand
- •Compact base to 98% Standard Proctor (ASTM D698) in 2-4" lifts
- •Double base depth in soft, wet, or cold-climate subgrade
ICPI/CMHA Tech Spec 18 — Permeable Interlocking Concrete Pavement (PICP)(ICPI/CMHA Tech Spec 18)
View StandardSets the open-graded aggregate structure for permeable pavement — three stone layers with no sand, designed to let stormwater infiltrate through the surface.
Key Requirements:
- •No. 2 stone subbase — 8" pedestrian, 12"+ vehicular
- •No. 57 stone base — 4" minimum
- •No. 8 chip stone bedding — 2"
- •Verify surface infiltration ≥100 in/hr (ASTM C1781) at acceptance
ICPI/CMHA Tech Spec 3 — Edge Restraints(ICPI/CMHA Tech Spec 3)
View StandardRequires edge restraint on sand-set and PICP installations to prevent lateral creep — the base footprint in this calculator extends 6" past the paved edge so restraint anchors into compacted base.
Key Requirements:
- •Edge restraint mandatory on sand-set and PICP installations
- •Base extends 6" past the paved surface on all sides
- •Spike/anchor into compacted base, never native soil
AASHTO M-288 — Geotextile Specification(AASHTO M-288)
View StandardThe specification for geotextile separation fabric recommended between subgrade and aggregate base on fine-grained or moist soils.
Key Requirements:
- •Separation fabric between soil and base on fine/moist subgrade
- •Prevents base aggregate from migrating into soil over time
- •Not required on well-draining, coarse-grained soils
Standards Disclaimer: Standards and codes are subject to periodic updates. Always verify current requirements with local building authorities and professional engineers before beginning construction. Links provided are for reference only.
Soil Conditions
Soft, wet, or expansive subgrade
Tech Spec 2's base depths assume reasonably competent, well-draining native soil. Soft clay, high water tables, or expansive soils call for a deeper base — Tech Spec 2 recommends doubling the base depth in these conditions, plus geotextile separation fabric.
Regional Examples:
Frost Climate
Base depth vs. frost heave
Unlike a footing, a paver base is not typically extended to the frost line — the open-graded, well-draining base itself resists frost heave better than solid soil. Some northern jurisdictions still specify a deeper base as a local amendment.
Regional Examples:
Sand-Set vs. PICP
Choosing the base system
Sand-set is the standard, lower-cost approach for most residential work. PICP (permeable) costs more in aggregate (three layers instead of two, deeper subbase) but manages stormwater on-site and is required or incentivized by some local stormwater ordinances.
Regional Examples:
Before You Build
- •Contact your local building department for specific requirements
- •Verify frost line depths, wind zones, and seismic requirements for your area
- •Check if permits are required and schedule required inspections
- •Consult with a local contractor familiar with local codes
Heavy material — watch the weight limit
Concrete, brick, and masonry hit tonnage caps fast. Most dumpsters cap heavy material at 10 tons, and overage fees stack quickly. See the disposal guide before you load.
Read the heavy-debris guide →
Related Calculators
Paver & Patio Calculator
Calculate pavers, base aggregate, bedding sand, polymeric sand, and edging for sand-set, mortar-set, pedestal & PICP installs. ICPI Tech Spec.
Gravel Calculator
How many tons of driveway gravel, pea gravel, or river rock do you need? Free calculator with per-material densities and compaction — yards, tons, bags.
Sand Calculator
Free sand calculator for mason, fill, concrete & play sand. Cubic yards, tons & 50-lb bags with compaction and wet-weight built in. ASTM C33/C144 densities.
How to Use This Calculator
- Enter the patio or driveway length and width.
- Pick the application — pedestrian patio, residential driveway, or light vehicular — which sets the minimum base depth.
- Choose sand-set (standard) or PICP (permeable, no sand) as your base method.
- If your subgrade is soft, wet, or in a cold climate, add extra base depth above the minimum.
- Check the geotextile box if your soil is fine-grained or stays moist.
- Click Calculate for the base and bedding material — depth, loose volume to order, and tons.
Why Order More Than the Finished Depth Suggests
Aggregate base doesn't stay the volume it started as once you compact it — loose crushed stone settles and interlocks under a plate compactor, losing roughly 20 to 25 percent of its volume in the process. That means if you need a finished, compacted base 4 inches deep, you have to spread and compact more than 4 inches of loose material to get there. This calculator's "order volume" already includes that factor, so the tonnage you see is what to actually order from the yard, not the bare finished-depth math that would leave you short. The same logic applies to bedding sand, though it's screeded rather than compacted, so it doesn't get the same multiplier. For permeable (PICP) systems, there's no sand at all — three layers of progressively finer open-graded stone let water pass straight through instead of running off, which is why the subbase alone often runs 8 to 12 inches deep, several times what a sand-set base needs.
Frequently Asked Questions
How much gravel do I need for a paver base?
It depends on the application and your patio or driveway's footprint. Per ICPI Tech Spec 2, a pedestrian patio needs 4 inches of compacted base, a residential driveway needs 6 inches, and a light-vehicular surface needs 10 inches — measured over a footprint that extends 6 inches past the paved edge on every side. Because loose aggregate compacts by about 20 to 25 percent, you need to order more material than the finished depth alone suggests; this calculator's order volume already includes that factor.
What's the difference between this and the Paver Calculator?
This calculator answers one question — how much base and bedding material you need — without asking you to pick a paver type, pattern, joint width, or edge restraint first. It's built for the planning stage, or for ordering base material on a separate schedule from the pavers. The full Paver Calculator produces a complete materials list: paver count, joint sand, edge restraint spikes, and sealer, in addition to the same base and bedding math. Both use the identical ICPI Tech Spec 2 depths and compaction factor, so the base numbers always agree — use this one when you only need the aggregate.
How deep should a paver base be?
The ICPI Tech Spec 2 minimums are 4 inches for a pedestrian patio, 6 inches for a residential driveway, and 10 inches for light-vehicular use like a parking pad or alley. These assume reasonably competent, well-draining native soil. On soft, wet, or expansive subgrade, double the base depth — this calculator has an extra-depth field for exactly that adjustment.
How much bedding sand do I need under pavers?
One inch, screeded flat and level — never compacted, and never used to correct a low or uneven base underneath. That 1-inch layer is what the pavers actually sit in and get tapped into place on. It's a fixed depth regardless of application (patio, driveway, or light-vehicular) — only the aggregate base depth below it changes with use.
What's a PICP base, and why doesn't it use sand?
PICP (permeable interlocking concrete pavement) is a base system designed to let stormwater soak through the surface instead of running off. It uses three layers of progressively finer, open-graded stone — a subbase, a base, and a bedding layer — with no sand anywhere, because sand would clog the gaps water needs to pass through. The subbase alone runs 8 to 12 inches deep depending on pedestrian vs. vehicular use, several times deeper than a standard sand-set base, which is why PICP typically needs more total aggregate even though it skips the sand.
Do I need geotextile fabric under my paver base?
It's recommended, not universally required — mainly on fine-grained soils like clay or silt, or anywhere the subgrade stays moist. The fabric (per AASHTO M-288) separates the soil from the aggregate base so they don't mix together over time, which would otherwise let the base slowly sink into softer soil beneath it. On coarse, well-draining native soil it's often skipped. Check the geotextile box in this calculator to get a fabric quantity if your site needs it.