Yes. ToolsBing tools are free to use online.

Do I need to create an account?

No. You can use this tool without signing up.

Is the result professional advice?

No. The result is an estimate or planning guide and should not replace qualified professional advice.

Can I use this result for planning?

Yes, but treat it as a starting point and compare it with your real situation before making a final decision.

What should I do after using the Retaining Wall Calculator?

Review the explanation, test one alternative scenario, and use the result as a starting point before making your final decision.

Why does this page include guidance below the tool?

The guidance helps you understand the result, avoid common mistakes, and choose a practical next step instead of only seeing a number.

Home / Construction Intelligence / Landscape & Outdoor Construction Intelligence / Retaining Wall Calculator

Retaining Wall Calculator

Calculate Landscape & Outdoor Intelligence

Estimate retaining wall blocks, base gravel, backfill, and drainage allowance.

Landscape and outdoor estimate note

Landscape and outdoor construction calculators on ToolsBing are planning estimates only. Confirm site measurements, slopes, drainage, soil condition, compaction, local code, utility locations, product coverage, supplier sizing, weather exposure, and contractor guidance before purchasing or installing materials.

Enter outdoor project inputs

Wall Length ftWall Height ftBlock Length inBlock Height inBase Depth inBackfill Depth inWaste %

Estimated result

Estimated quantityWaiting for input

pieces / units

MeaningPlanning estimate

This is an early outdoor material, spacing, volume, or cost estimate before field verification.

Next stepVerify site conditions

Confirm slope, drainage, compaction, utilities, access, delivery, product coverage, local rules, and installer guidance.

Retaining wall material breakdown

Cap blocks—

Assumes 12-inch cap units

Compacted base gravel—

cubic yards; assumes a 24-inch-wide base

Drainage backfill—

cubic yards behind the full wall height

Drain pipe—

linear feet including 10% allowance

Formula and assumptions

Blocks = wall area ÷ block face area × (1 + waste %). Base and backfill volumes use the entered depths; drain pipe follows wall length with a 10% allowance.

Use this result as a preliminary outdoor construction estimate. Real projects may require excavation, grading, drainage, compaction, edging, permits, safety clearance, and professional review.

How to use this retaining wall estimate

Measure the finished wall length and exposed height.
Enter the face dimensions printed for the exact block you plan to buy.
Set base and drainage depths for your site plan, then add a realistic waste allowance.
Compare the result with the manufacturer installation guide and local permit requirements before ordering.

What this estimate includes

Face blocks, top-course cap units, compacted base gravel, drainage backfill, and drain pipe allowance. It does not size geogrid, reinforcement, footings, excavation, labor, delivery, or engineering.

When professional design is needed

Wall height alone is not the only risk. Slope, surcharge loads, weak soil, water pressure, nearby structures, and local code can require engineered design even for a shorter wall.

Related landscape and outdoor calculators

Check before using this result

Verify the inputs, units, assumptions, and any local rules that apply. For financial, health, engineering, or construction decisions, confirm the result with a qualified professional or an authoritative source.