Sandbag Calculator: How Many Sandbags Do I Need?

Two minutes here can save hours in a storm. Tell us the length and height you need to block, and get a ready-to-build sandbag layout.

Quickly size a doorway or perimeter barrier using the recommended 3:1 base-width “pyramid” method. Enter your opening/length and target water height, we’ll add freeboard and compute total bags, layers, footprint, pallets, and estimated weight.

👉 Assumptions baked in: standard 14″×26″ bags, placed ~4″ high × 10″ wide × 14–16″ long; recommended 3:1 base-width:height (“pyramid”); USACE bag counts per 100 ft for 1–4 ft levees drive the math (converted to a per-foot formula). Sources at the end.

Opening width

Standard exterior door ≈ 3 ft; single garage ≈ 8–9 ft.

Side returns (each)

Wrap the barrier past both jambs for stability (default 2 ft each side).

Expected water height

Tip: estimate conservatively.

Freeboard (extra safety height)

Commonly 6–12 inches.

Bag weight assumption

Half-filled bags stack better and seal joints.

Pallet size

Design length (U-wrap)

ft total (opening + both returns)

Design height (incl. freeboard)

ft • layers • ~ ft base width

Sandbags required

bags • ≈ pallets

Estimated weight

lbs total • ≈ trips @ lbs capacity

Stacking plan (doorway): build a short U-shaped dike that wraps past both jambs. Use the pyramid method: stamp bags, stagger joints, alternate headers (crosswise) and stretchers (lengthwise). Plastic sheeting on the water-side face improves seal.

Layer	Bags across (width)	Approx. course thickness	Notes

Calculations use USACE bag/height relationships for 3:1 base-width levees (converted to bags per foot) and typical placed bag dimensions ≈4″ high × 10″ wide × 14–16″ long.

Run length to protect

Linear feet along doors, walls, or yard perimeter.

Expected water height

Freeboard (extra safety height)

Bag weight assumption

Pallet size

Design length

Design height (incl. freeboard)

ft • layers • ~ ft base width

Sandbags required

bags • ≈ pallets

Estimated weight

lbs total • ≈ trips @ lbs capacity

Stacking plan (run): build with a base ≈ 3× the design height. Stamp each bag in place, keep joints staggered, interleave header & stretcher courses. Tarps/visqueen on the water-side face help seal.

Layer	Rows across (width)	Approx. course thickness	Notes

Based on USACE “pyramid” placement with 3:1 base-width and typical bag dimensions ≈4″ high × 10″ wide × 14–16″ long.

Pickup/Trailer load planning
Enter your safe payload to estimate trips:

lbs capacity per trip

FYI: 30–33 lb per bag is common; some jurisdictions cap ~1,000 lb for “half-ton” pickups.

Safety notes
Sandbag levees above ~3 ft are labor-intensive and unstable without supports. For taller barriers or long runs, consider commercial flood panels/tubes or consult local emergency management.

This planner provides estimates for emergency planning only; site conditions vary.