Retaining Wall Block Calculator
Enter your wall dimensions and block size to get your custom material list.
How to Use the Retaining Wall Block Calculator
Using this wall block calculator is incredibly simple. Just measure your planned project area and input your specific block dimensions to get your custom material list:
Price Per Block ($): (Optional) Enter the cost of a single block to use this tool as a block retaining wall cost estimator.
Wall Length (Feet): Enter the total continuous length of the retaining wall you plan to build.
Wall Height (Feet): Enter how tall you want the final retaining wall to be (measure from the buried base trench to the top cap).
Block Length (Inches): Input the length of a single retaining wall block (commonly 11.5″, 12″, or 16″ inches).
Block Height (Inches): Input the height of a single retaining wall block (commonly 4″ or 6″ inches).
Introduction
Planning a new landscaping project and wondering exactly how much material to buy? Building a block retaining wall is an incredible way to level out a sloped yard, build raised garden beds, or define your patio space. However, guessing your material count at the lumber yard usually leads to buying too few blocks (delaying your project) or buying too many (wasting your hard-earned money).
Whether you are using standard landscape blocks from a big box store or premium systems like Allan Block and Versa-Lok, our free retaining wall block calculator takes the guesswork out of the process. By simply entering the dimensions of your wall and the size of your chosen blocks, this retaining wall cost calculator will generate your exact block count and total estimated price instantly.
How Many Retaining Wall Blocks Do I Need?
If you are just doing some quick planning and want a general rule of thumb for estimating your landscape block calculator needs, here is the basic math:
- The 10% Rule: Always add 10% to your final block count to account for cut pieces, corners, and potential breakage during the build.
- Calculate Wall Area: Multiply your total wall length (in feet) by your total wall height (in feet) to find the square footage of the wall.
- Calculate Block Area: Multiply the block length (in inches) by the block height (in inches), then divide by 144 to get the square footage of a single block.
- The Formula: Divide the total wall square footage by the single block square footage to get your total block count.
Frequently Asked Questions
Q. How to build a retaining wall with blocks?
A. Building a concrete retaining wall with blocks requires three main steps: 1. Dig and perfectly level a trench for the footing. 2. Add and compact a gravel base (usually 4 to 6 inches deep). 3. Lay your first course of blocks perfectly level, then stack the remaining courses while backfilling with landscape gravel behind the wall for proper drainage.
Q. Do I need a retaining wall footing calculator or backfill calculator?
A. Yes, blocks are only one part of the equation! A proper retaining wall needs a compacted gravel base (footing) and gravel backfill behind the blocks to relieve water pressure. You will generally need to dig a trench deep enough to bury half of your first row of blocks, plus 4 to 6 inches for the gravel base.
Q. Can I use this as a circular retaining wall block calculator?
A. Yes! If you are building a circle retaining wall block design (like a fire pit or curved garden bed), you just need to determine the total circumference of the circle in feet. Enter that circumference into the “Wall Length” input field above to get your estimated block count.
Planning your next project? Browse our master hub of Free DIY Home & Garden Calculators to get instant material lists, spacing math, and budget estimates.