Sandbag barriers get wider at the base as they get taller, so the number of bags grows quickly with height. Enter the length and height of the barrier; the calculator uses the US Army Corps of Engineers figures for a sandbag levee.
Bags per 100 ft of barrier
| Height | Bags per 100 ft | Bags per foot |
|---|---|---|
| 1 ft | 600 | 6 |
| 2 ft | 2,100 | 21 |
| 3 ft | 4,500 | 45 |
| 4 ft | 7,800 | 78 |
These figures are from the US Army Corps of Engineers Northwestern Division pamphlet Sandbagging Techniques. A single row of bags one foot high takes about 300 bags per 100 ft, but a levee needs a wider, pyramid-shaped base to stay stable, which is why the counts rise so fast.
Formula
Bags = barrier length × bags per foot for the height
Worked example: 50 ft barrier, 2 ft high
- Bags per foot at 2 ft: 21.
- 50 × 21 = 1,050 bags.
Practical tips
- Fill bags about one-half to two-thirds full so they lie flat and interlock.
- Lay bags lengthwise along the flow, with the folded tops tucked under, overlapping like bricks.
- Follow local emergency management guidance; they may provide sand and bags during a flood warning.
Questions
How many sandbags for a 100 ft wall, 1 ft high?
About 600 bags.
How many sandbags to protect a doorway?
A 3 ft doorway barrier 1 ft high takes about 18 bags; plastic sheeting under the bags improves the seal.
Do sandbags stop all water?
No. They slow and divert water; some seepage is normal.
Sources
- Sandbagging Techniques, U.S. Army Corps of Engineers, Northwestern Division (hosted by Utah State University Extension).
Used for: Bags per 100 linear ft: 600 at 1 ft, 2,100 at 2 ft, 4,500 at 3 ft and 7,800 at 4 ft.