How Many Sandbags Do I Need?

The short answer

For standard 14×26 inch sandbags laid lengthwise in a staggered pyramid, plan on about 600 bags per 100 linear feet of 1 ft wall, 1,400 bags for a 2 ft wall, and 2,400 bags for a 3 ft wall. Sand works out to roughly 80 filled bags per cubic yard, so a 100 ft, 1 ft wall needs about 7.5 cubic yards of sand (about 10 tons). Fill each bag one-half to two-thirds full — never to the top — and add 10% to every order for damaged bags and restocking.

The bag math: bags per 100 linear feet

Sandbag counts grow faster than wall height because a taller wall needs a wider base. The table below uses the staggered-pyramid method with a flat working top (see the arithmetic below the table):

These are planning approximations, not guarantees: bag size, fill level, and how aggressively you overlap all move the number a few percent either way. For walls under 100 feet, scale linearly — a 50 ft, 1 ft wall needs about 300 bags.

How the estimate works (the pyramid arithmetic)

The derivation uses stated assumptions so you can adjust it to your wall: a filled 14×26 inch bag laid flat is about 4 inches thick, and with 2 inches of overlap each bag covers 24 inches of wall length — that's 50 bags per 100 feet for a single bag-wide row. A 1 ft wall is 3 courses, a 2 ft wall is 6, and a 3 ft wall is 9. Each course sits one bag narrower than the one below (the pyramid), with a flat top you can walk or work on, and the base widens roughly 2 bags for every foot of height for stability:

If your bags are a different size, redo the arithmetic with your bag's effective length: 100 feet divided by effective bag length in feet gives your per-row count, and the pyramid widths above stay the same.

Bags for shorter runs

Most homeowner projects are a doorway, a garage mouth, or a short stretch of foundation — not 100 feet. Scale the per-100-ft figures down:

Doorways and vents are the classic use: a standard 3 ft door needs a 2-course (about 8 inch) wall across its width plus a foot of overlap on each side — roughly 10 to 15 bags per doorway. Work out your sand order with our sand calculator once you have the bag count.

How much sand to order

Suppliers commonly figure about 80 filled sandbags per cubic yard of sand — a filled 14×26 inch bag holds roughly one-third of a cubic foot of sand (the 0.33–0.45 cu ft range), and 27 ÷ 0.34 lands right around 80. Divide your bag count by 80:

Sand weighs about 2,700 pounds per cubic yard (1.35 tons per yard), so even a modest wall is heavy freight: 7.5 yards is over 10 tons. If you're converting between units, our cubic feet to cubic yards calculator handles the volume side, and our cubic yard weight guide covers what that means for trucks and trailers.

Bagged vs bulk sand: when bulk wins

This decision is about logistics more than unit price — bulk sand is cheaper per yard at essentially any quantity. A 50 lb bag of all-purpose sand (about half a cubic foot) typically runs $5–$7 at a home center, so one cubic yard of bagged sand costs roughly $270–$380. Bulk sand from a landscape supplier runs roughly $30–$60 per ton (about $40–$80 per yard) plus a delivery fee in the $50–$100 range. Prices vary by market; get a local quote before you commit.

The practical crossover sits around 1 cubic yard (about 80 bags): below that, a delivery minimum and the delivery fee make bagged sand the simpler choice — you can haul it in a car or pickup in one trip. Above it, bulk wins on both price and labor: a single dumped pile next to your filling station beats opening and emptying hundreds of retail bags. For a 2 ft, 100 ft wall (17.5 yards), bulk isn't just cheaper — it's the only sane option.

How full to fill each bag

One-half to two-thirds full is the rule, and it matters more than it sounds. A half-filled bag drapes and molds into the gaps around its neighbors, creating a tight, interlocking wall; a stuffed bag is a rigid pillow that leaves voids water pours through. After filling, fold or tuck the open end under the bag — don't tie it off. Tied ends create a lump that prevents the next course from seating flat. Set up a filling station: one person holds the bag open (a traffic cone or a cut-off bucket makes a good collar), one shovels, and a third ties off and stacks. Keep a consistent fill — uneven bags make an uneven wall.

Bag types and sizes

The standard 14×26 inch woven polypropylene bag is what every table on this page assumes — it's the flood-fight workhorse, cheap in bundles of 50 or 100, and UV-treated versions survive a season or more in the sun. Burlap bags are the traditional alternative: they grip each other better when stacked and biodegrade, but they rot faster when wet and cost more. Larger 18×30 inch bags exist for bigger barriers but are heavy (50+ lb filled) and harder for one person to place precisely. For doorways and vents, long tube sandbags (sometimes sold as flood tubes) seal a threshold in one piece with no stacking. Whatever you buy, keep spares dry and out of sunlight until you need them — UV is what kills stored bags.

How to stack a sandbag wall that holds

Clear debris and vegetation from the wall line first — bags conform to the ground, and a lumpy base makes a leaky wall. Lay the bottom course with the folded/tucked ends facing the same direction (upstream, toward the water), and stagger each course like brickwork so no vertical seam runs through two courses. Tamp each course flat with your foot or a hand tamper before laying the next — this seats the bags and closes gaps. On the water side, drape plastic sheeting (visqueen) over the face of the wall and tuck it under the bottom course: the plastic does most of the waterproofing, while the bags hold it in place and add mass. Extend the sheeting a few feet out onto the ground on the water side and weigh it down. Finish by walking the wall and pressing any bridged gaps closed.

Check for free sandbags before you buy

During flood threats, many counties, cities, and fire districts run free sandbag and sand distribution sites — usually at fire stations or public works yards, sometimes with a per-household limit (25–50 bags is common). Call your county's emergency management office or non-emergency fire line; these programs often aren't well advertised online. The honest caveat: they activate during emergencies, not before, and popular sites run out. If you live somewhere that floods regularly, keeping a bundle of empty bags and a yard of sand on hand beats joining the line during the storm. Sandbags also see year-round use for erosion control, construction ballast, and temporary berms — demand spikes hardest during flood and hurricane season, so buy off-season if you can.

Common mistakes

Overfilling the bags. Two-thirds max — rigid bags don't seal. Stacking seams in line. Stagger every course like brickwork. Skipping the plastic. Bags alone slow water; sheeting on the water side stops most of it. Using dirt instead of sand. Soil turns to mud and the wall slumps. Ordering exact quantities. Bags tear, fills vary, and you'll restack sections — the 10% overage is cheap insurance. Building too tall. Past 3 feet, a sandbag wall is an engineered structure, not a stack of bags. For the volume math behind any of this, our cubic yard calculator is the fastest check.