Concrete Bag Order Sheet
Check the weight before the bag count. That is what decides whether this is a bag job or a truck job.
BFCBrilliance · bfcbrilliance.com/tools/concrete-bag-calculator
The pour
- Location
- Date
- Length
- Width
- Thickness
- CUBIC FEET
- Cubic yards
- Bag size
- Waste %
- BAGS
- TOTAL WEIGHT
- Water needed
Bag yields — the whole calculation
- 80 lb bag
- 0.60 cu ft — 45 per cubic yard
- 60 lb bag
- 0.45 cu ft — 60 per cubic yard
- 40 lb bag
- 0.30 cu ft — 90 per cubic yard
- A cubic yard
- 27 cubic feet
- ⚠ 1 cu yd in 80 lb bags
- 3,600 lb — nearly two TONS
- Volume
- length x width x (thickness in / 12)
- Waste
- 5-10%, more on a rough subgrade
- Water
- about 3 quarts per 80 lb bag — FOLLOW THE BAG
- ⚠ Running short means
- a COLD JOINT — a permanent weak plane
- Cylinder volume
- π x radius² x depth
Sections — break irregular shapes into rectangles
| Section | Length | Width | Thickness | Cubic ft | Bags |
|---|---|---|---|---|---|
Before mixing anything
- Weight checked — is this really a bag job?
- Ready-mix priced too, if anywhere near a cubic yard
- Subgrade levelled and compacted — it drives the waste figure
- An extra bag bought; unopened ones go back
- Enough help and mixing capacity to pour it in ONE session
- Forms built, braced and checked square before the first bag opens
- Water measured to the bag's ratio, not judged by eye
- Everything to hand — you cannot pause once it is mixed
- Weather checked: not into a hard frost, not into heavy rain
- Leftovers stored sealed, dry and OFF the floor
The weight is the real answer
One cubic yard is forty-five 80 lb bags — 3,600 pounds to buy, carry, lift and mix one at a time. Ready-mix is usually cheaper and always easier around that point. Read the weight output before the bag count; it is what actually decides the job.
You cannot pause a pour
Concrete starts setting the moment it is mixed. A slab poured in two sessions an hour apart carries a cold joint — a permanent plane of weakness where the pours never bonded. Running short is a structural defect here, not a second trip to the store. Buy the extra bag.
More water is weaker concrete
Extra water makes a mix easier to work and measurably weaker, and it is the commonest way a home pour ends up under strength. Mix to the bag's stated ratio. If it feels stiff, mix it longer — not wetter.