Gravel Calculator .org

Material guide

Gravel types and uses

Compare crushed stone, pea gravel, river rock, decomposed granite, limestone, and road base by particle shape, compaction, drainage, and common project use.

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Gravel material comparison

Product names vary by supplier and region. Use this table to ask better questions, then confirm the exact gradation and specification locally.

MaterialParticle shapeCompactionDrainageTypical planning use
Crushed stoneAngularVaries with finesGood when cleanBases, drainage, driveways
Pea gravelRoundedLow interlockGoodContained paths, patios, beds
River rockRoundedLow interlockGoodSwales, borders, decorative beds
Decomposed graniteFine, angularCan compact firmlyProduct dependentPaths and patio surfaces
Limestone gravelAngularProduct dependentProduct dependentDriveways, bases, paths
Road baseMixed angular sizesHigh when specifiedLower than clean stoneLoad-bearing base layers

Decision factors

Choose gravel by function

Appearance matters, but particle behavior and the project section determine whether a surface stays useful.

Interlock

Angular particles resist movement

Crushed aggregate locks together better than rounded stone, especially when a specified blend includes compactable fines.

Drainage

Open voids need an outlet

Clean stone can move water through the layer, but drainage still needs suitable fabric, slope, surrounding soil, and a discharge path.

Comfort

Foot traffic changes the choice

Small rounded stone feels different from a firm compacted surface. Consider furniture, wheels, mobility, maintenance, and edging.

Material details

What each gravel type does well

Crushed stone

Mechanically broken rock has angular faces that can interlock. Clean crushed stone leaves more open voids, while dense-graded blends include fine particles for tighter compaction. Use the exact supplier product in the project specification.

Pea gravel

Small rounded particles provide a softer visual texture and good surface drainage. They move under load, so pea gravel performs best inside firm edging and away from applications that require strong particle interlock.

River rock

Rounded river rock is often selected for drainage features and decorative landscapes. Larger particles are difficult to walk on and can expose weed fabric when they shift.

Decomposed granite

Fine weathered granite can compact into a relatively firm path or patio surface. Stabilized and unstabilized products behave differently, so follow the product installation requirements.

Limestone and road base

Limestone is available in many sizes and blends. Road base is a functional category rather than one universal recipe. Local quarry specifications determine gradation, compaction, and density.

Quick answers

Questions about gravel types

What is the best gravel for a driveway?

A driveway commonly uses a compactable angular base and an angular surface aggregate. The exact gradation should match local soil, drainage, climate, and load requirements. Rounded pea gravel is more likely to shift under tires.

Which gravel drains best?

Clean, open-graded aggregate leaves connected voids that allow water to pass. A dense-graded product with many fines compacts more tightly and usually drains less freely. The surrounding soil and outlet are also important.

What gravel is comfortable for walking?

Small rounded pea gravel can feel comfortable underfoot, but it shifts and may challenge wheels or mobility devices. Compacted decomposed granite can create a firmer path when it is correctly specified and installed.

Can different gravel types use the same density?

Not reliably. Particle shape, size distribution, moisture, and fines change bulk density. Use the calculator material presets for planning and a supplier density for ordering.