Calculate exactly how many 40lb, 60lb, or 80lb bags of concrete mix you need for any slab, footing, column, or step project. Instant bag count, cubic yards, cubic feet, and total cost estimate — Quikrete and Sakrete compatible.
A concrete bag calculator for the USA tells you exactly how many bags of premixed concrete — whether 40lb, 60lb, or 80lb — you need to buy for your project, so you never overbuy or run short mid-pour. It works by calculating the volume of your project in cubic feet, dividing by the yield of your chosen bag size (0.30, 0.45, or 0.60 cu ft), and adding a standard 10% waste allowance recommended by Quikrete and Sakrete. This free calculator handles five project shapes — rectangular slabs and footings, square/round columns, and concrete steps — plus a cost estimator that shows total material cost at current US retail bag prices. It also converts your volume to cubic yards so you can decide whether bags or a ready-mix truck delivery makes more economic sense for your project size.
🧱 Concrete Bag Calculator — USA
Select your project shape, enter dimensions, choose bag size and get an instant bag count with cost estimate.
📐 Slab Dimensions
Enter the longest side of the slab in feet.
Typical: 40lb ≈ $4.98, 60lb ≈ $6.98, 80lb ≈ $8.48 at Home Depot / Lowe's (2026).
🧱 Slab Bag Calculation
Results below
Bags Required
—
60lb bags
Volume (cu ft)
—
cubic feet
Volume (cu yd)
—
cubic yards
Estimated Cost
—
USD total
—
40 lb Bags Needed
—
60 lb Bags Needed
—
80 lb Bags Needed
📋 Slab Summary
💡 Project Tips
📐 Footing / Foundation Dimensions
Total linear run of footing. For perimeter footings, enter total perimeter length.
Typical: 16" wide for standard wall footing, 24"+ for column footings.
Typical: 8–12" deep for residential, 12–24" for commercial footings.
▬ Footing Bag Calculation
Results below
Bags Required
—
80lb bags
Volume (cu ft)
—
cubic feet
Volume (cu yd)
—
cubic yards
Estimated Cost
—
USD total
—
40 lb Bags
—
60 lb Bags
—
80 lb Bags
📋 Footing Summary
💡 Footing Tips
⬛ Column / Post / Sonotube Dimensions
For round: tube diameter. For square: width of one side.
Below-grade depth for fence posts; total height for above-grade columns.
⬛ Column Bag Calculation
Results below
Total Bags
—
40lb bags
Volume per Column
—
cubic feet
Total Volume
—
cubic feet
Estimated Cost
—
USD total
—
40 lb Bags
—
60 lb Bags
—
80 lb Bags
📋 Column Summary
💡 Post Tips
Calculate bags for concrete steps. Each step is approximated as a rectangular solid — width × rise × run. For a standard staircase, enter each step's dimensions and number of steps.
🪜 Step Dimensions
Width across the step (side to side). Typical: 36–60 inches.
Vertical height per step. IBC: 4"–7.75" max rise.
Horizontal depth per step. IBC: 10" minimum run (tread).
🪜 Steps Bag Calculation
Results below
Total Bags
—
60lb bags
Volume (cu ft)
—
cubic feet
Volume (cu yd)
—
cubic yards
Estimated Cost
—
USD total
—
40 lb Bags
—
60 lb Bags
—
80 lb Bags
📋 Steps Summary
💡 Step Pouring Tips
Already know your volume in cubic yards or cubic feet? Enter it here to compare bag sizes and costs side by side, and find out at what volume a ready-mix truck delivery becomes cheaper than bags.
📦 Known Volume
Typical US ready-mix price 2026: $140–$200/cu yd depending on region and mix.
💰 Cost Comparison
Bag vs. Ready-Mix
40 lb Bag Total Cost
—
USD
60 lb Bag Total Cost
—
USD
80 lb Bag Total Cost
—
USD
Ready-Mix Cost
—
USD
—
40 lb Bags Needed
—
60 lb Bags Needed
—
80 lb Bags Needed
📋 Cost Summary
💡 Best Value Recommendation
📦 Concrete Bag Yield by Size — USA (Quikrete / Sakrete)
Slab / Patio
V = L × W × (T/12)
Footing
V = L × (W/12) × (D/12)
Round Tube
V = π × r² × H / 1728
Steps
V = Σ W × Rise × Run
0.30
cu ft per 40 lb bag
0.45
cu ft per 60 lb bag
0.60
cu ft per 80 lb bag
Slab / PatioFootingRound TubeSteps
How Does a Concrete Bag Calculator Work?
A concrete bag calculator converts your project's dimensions into a volume (cubic feet or cubic yards), then divides by the yield of your chosen bag size to give you the exact number of bags needed. The official Quikrete and Sakrete yield figures — used by this calculator and every major US home improvement retailer — are: 40 lb bag = 0.30 cu ft, 60 lb bag = 0.45 cu ft, and 80 lb bag = 0.60 cu ft. These yields assume the standard water-to-cement ratio printed on the bag (approximately 0.5 gallons of water per 60 lb bag for Quikrete 5000). A 10% waste allowance is added by default — the industry-standard overage recommended by Quikrete, Sakrete, and the Portland Cement Association for all DIY bag projects.
🔵 Bags vs. Ready-Mix — When to Use Which
For projects under 1 cubic yard (27 cubic feet), bagged concrete mix is almost always cheaper and more practical than ordering a ready-mix truck. At 2026 average US prices, 1 cubic yard using 80 lb bags costs approximately $380 in bags vs. $140–$200 per cubic yard for ready-mix — but ready-mix has a typical minimum order of 1 yard and a delivery/truck charge of $150–$300. So for projects under 0.5 cubic yards, bags always win on cost. For projects over 1.5–2 cubic yards, ready-mix is usually cheaper once you factor in bag handling, mixing time, and labor. The break-even point is around 0.75–1.0 cubic yard depending on your local ready-mix pricing.
📦 Choosing the Right Bag Size
The 80 lb bag gives the best cost-per-cubic-foot value but weighs as much as a small person — difficult to handle alone, especially for mixing by hand. The 60 lb bag is the most popular for DIY projects — a good balance of yield and manageability. The 40 lb bag is ideal for small pours (post holes, repairs), mixing in a bucket, or when working alone on a tight site. For fence post holes, Quikrete Fast-Setting Concrete (50 lb bag) is a popular dry-pour option that eliminates mixing entirely.
⚗️ Quikrete vs. Sakrete — Bag Yields
Both Quikrete and Sakrete use the same standard yields per bag: 40 lb = 0.30 cu ft, 60 lb = 0.45 cu ft, 80 lb = 0.60 cu ft. These are published on the product bags and product data sheets. Quikrete 5000 (high-early-strength) and Quikrete Fast-Setting Concrete have the same volume yield per bag as standard Quikrete 4000. The difference is in compressive strength and cure time — not yield. Always verify the yield on your specific product's data sheet before ordering large quantities.
💧 Water Requirements per Bag
Quikrete 80 lb bag requires approximately 3 quarts (0.75 gallon) of water. A 60 lb bag requires approximately 2.25 quarts. A 40 lb bag requires approximately 1.5 quarts. Always add water gradually — too much water is the single biggest cause of weak concrete. The mix should be workable but not sloppy. A proper mix holds its shape when squeezed but releases a little water — similar in consistency to peanut butter. For structural pours, target a water-to-cement ratio below 0.50.
Concrete Volume Formulas — All Shapes
All four shapes handled by this calculator use straightforward geometry. The key is converting all dimensions to consistent units (feet or inches) before calculating. Volume in cubic feet is then divided by bag yield to get bag count — and divided by 27 to convert to cubic yards for ready-mix ordering.
📐 Concrete Volume Formulas — USA Bag Calculator
Slab: V (cu ft) = Length (ft) × Width (ft) × Thickness (in) / 12
Footing: V (cu ft) = Length (ft) × Width (in)/12 × Depth (in)/12
Round Column: V (cu ft) = π × (Diameter/24)² × Height (in)/12
Square Column: V (cu ft) = (Width/12)² × Height (in)/12
Steps: V (cu ft) = Σ Width(in)/12 × Rise(in)/12 × Run(in)/12 [per step, multiplied by stair number factor]
Convert: 1 cubic yard = 27 cubic feet
Bags (40lb) = V (cu ft) × (1 + waste%) ÷ 0.30 → round UP to nearest whole bag
Bags (60lb) = V (cu ft) × (1 + waste%) ÷ 0.45 → round UP
Bags (80lb) = V (cu ft) × (1 + waste%) ÷ 0.60 → round UP
Example: 10×10 slab at 4" thick → V = 10×10×(4/12) = 33.33 cu ft + 10% = 36.67 cu ft
When calculating bags, always round up to the next whole bag — never down. Running out of concrete mid-pour is far worse than having a spare bag or two. Cold joints (where fresh concrete meets partially set concrete) are a serious structural and aesthetic defect. For critical pours — footings, structural slabs, fence posts — buy one or two extra bags beyond the calculator result and return any unopened bags. Most US home improvement stores accept returns of unopened concrete bags within 90 days with a receipt.
Concrete Bag Coverage Quick Reference — USA
The table below shows how many bags you need for the most common residential concrete projects in the USA, pre-calculated at standard dimensions. All values include a 10% waste allowance and use Quikrete/Sakrete standard yields.
Project
Dimensions
Volume (cu ft)
40 lb Bags
60 lb Bags
80 lb Bags
Cost (60lb @ $6.98)
Walkway — 3 ft × 10 ft
3′×10′ × 4″
10.0
37
25
19
$174.50
Small Patio — 8 ft × 8 ft
8′×8′ × 4″
21.3
78
52
39
$362.96
Standard Patio — 10 ft × 12 ft
10′×12′ × 4″
40.0
147
98
74
$684.04
Garage Slab — 20 ft × 20 ft
20′×20′ × 4″
133.3
489
326
245
Use ready-mix
Fence Post Hole (round)
10″ dia × 24″
1.09
4
3
2
$20.94
Deck Post — 4 posts
10″ dia × 36″ × 4 posts
6.55
24
16
11
$111.68
Wall Footing — 20 ft run
20′ × 16″W × 10″D
22.2
82
55
41
$383.90
Concrete Steps — 3 steps
48″W × 7″R × 11″Run
6.4
26
17
13
$118.66
Sonotube — 12″ dia × 48″
12″ dia × 48″H
3.14
12
8
6
$55.84
Driveway Apron — 10 ft × 5 ft
10′×5′ × 6″
25.0
92
62
46
$432.76
🚶 Walkways & Patios
Walkway 3×10 ft (4")25 × 60lb bags
Small Patio 8×8 ft (4")52 × 60lb bags
Patio 10×12 ft (4")98 × 60lb bags
Driveway Apron 10×5 ft (6")62 × 60lb bags
🪺 Posts & Footings
Fence Post 10″ dia × 24″3 × 60lb bags
Deck Post 4 posts (10″×36″)16 × 60lb bags
Wall Footing 20 ft × 16″×10″55 × 60lb bags
Sonotube 12″ dia × 48″8 × 60lb bags
🪜 Steps & Large Slabs
Concrete Steps — 3 steps (48″W)17 × 60lb bags
Garage Slab 20×20 ft (4")Use ready-mix
Ready-Mix break-even point~0.75–1.0 cu yd
Choosing the Right Concrete Mix by Project
Not all bagged concrete is the same — different Quikrete and Sakrete product lines are formulated for different applications. Using the wrong product is one of the most common DIY concrete mistakes in the USA.
🏠
Quikrete 5000 — High Strength (4,000 PSI)
The go-to mix for structural applications — footings, slabs, columns, and steps. Achieves 5,000 PSI compressive strength in 28 days. Reaches 3,500 PSI in just 3 days, making it ideal for faster form removal. Available in 80 lb bags at Home Depot, Lowe's and Menards nationwide. Best all-around choice for serious DIY projects.
⚡
Quikrete Fast-Setting — Posts & Piers
Sets in 20–40 minutes — no mixing required for fence posts and mailbox posts. Simply pour dry mix into the hole around the post and add water. Reaches 4,000 PSI in 28 days. Available in 50 lb bags. Not suitable for slab, footing, or step pours — only for post-setting applications. Yield: 0.375 cu ft per 50 lb bag.
🔧
Quikrete Countertop Mix
Specially formulated for concrete countertops — low shrinkage, glass-fiber reinforced, flowable consistency for complex forms. Achieves 6,000 PSI. Available in 80 lb bags. Not a general-purpose concrete — yield and workability are optimized for countertop thickness (1.5–2 inches). Higher water demand than standard mixes; use a mixer drill for best results.
❄️
Sakrete 5000 Plus — All Weather
Sakrete's equivalent to Quikrete 5000 — with enhanced performance in cold and hot weather. Suitable for all structural applications. Both Quikrete and Sakrete bags yield the same 0.30/0.45/0.60 cu ft per 40/60/80 lb bag — so this calculator works equally for both brands. Check your local store for brand availability and pricing.
🎨
Quikrete Vinyl Concrete Patcher
For repairing existing concrete — cracks, spalls, damaged edges. Not a structural pour product. Bonds to existing concrete without bonding agent when properly prepared (surface must be clean, moist, and SSD condition). Much higher cost per cu ft than standard mix but excellent for repairs under 2 inches deep. Available in 40 lb bags only.
🏗️
When to Order Ready-Mix Instead
If your project exceeds 1 cubic yard (27 cu ft = approx. 300 × 80 lb bags), seriously consider ready-mix delivery. At $160/cu yd average, a 2 cu yd driveway slab = $320 in ready-mix vs. $500+ in bags — plus bags require significant labor, mixing equipment rental, and physical strain. Contact your local concrete plant (search "concrete plant near me") for a no-obligation quote before committing to bags for any large pour.
✅ Worked Example — 10 ft × 12 ft Backyard Patio, 4" Thick
Step 1 — Volume: V = 10 × 12 × (4/12) = 10 × 12 × 0.333 = 40.0 cu ft. Step 2 — Add 10% waste: 40.0 × 1.10 = 44.0 cu ft. Step 3 — Bag count: 40 lb bags = ceil(44.0 / 0.30) = ceil(146.7) = 147 bags. 60 lb bags = ceil(44.0 / 0.45) = ceil(97.8) = 98 bags. 80 lb bags = ceil(44.0 / 0.60) = ceil(73.3) = 74 bags. Step 4 — Cost at Home Depot prices: 60 lb bags: 98 × $6.98 = $684. 80 lb bags: 74 × $8.48 = $628. Ready-mix (1.48 cu yd): 1.48 × $160 = $237 materials + $200 delivery = $437. Verdict: Ready-mix is cheapest for this size pour — consider ordering ready-mix if you can work fast enough to place 1.5 cu yd before it stiffens.
Pro Tips for Mixing Bagged Concrete — USA
Use a mixer for any pour over 5 bags — hand-mixing in a wheelbarrow is exhausting and produces inconsistent results for large pours. Rent a portable electric cement mixer from Home Depot or Lowe's for $40–$60/day for pours of 10–100 bags.
Never pour directly onto dry, dusty ground — dampen the subbase before pouring to prevent the ground from absorbing water from the mix. A dry subbase will draw water out of fresh concrete, weakening the surface layer and causing surface defects.
Add water sparingly — the mix consistency is more important than ease of pouring — the #1 DIY concrete mistake is adding too much water because the mix feels stiff. Excess water increases w/c ratio, dramatically reducing strength and causing excessive cracking. Add water in small amounts and mix thoroughly between additions.
Always cure concrete after placement — cover the slab with plastic sheeting or apply a curing compound within 20 minutes of finishing. Keep the slab moist for a minimum of 7 days. Proper curing increases final strength by 30–50% compared to air drying.
Cold weather pours — don't pour below 40°F (4°C) — frozen water in the mix permanently damages hydration. In temperatures below 50°F, use warm mixing water and cover the finished slab with insulated blankets. Quikrete Accel-Set additive can accelerate cure in cool weather. Never pour on frozen ground.
Hot weather pours — work fast and work early — in summer temperatures above 85°F, use cold water (add ice to mixing water), pour in the early morning to avoid direct sun, and have all forms, tools, and people ready before you open the first bag. Set time can drop from 2 hours to 45 minutes in extreme heat.
Don't skimp on slab thickness for driveways — a 4-inch slab is the minimum for pedestrian use. Passenger vehicle driveways require 4–5 inches. If heavy trucks (delivery, moving, RV) will use the driveway, specify 6 inches minimum. The cost difference between a 4" and 6" driveway slab is surprisingly small — approximately 50% more material for twice the load-carrying capacity.
❓ Frequently Asked Questions — Concrete Bag Calculator USA
How many 80 lb bags of concrete do I need for a 10x10 slab?+
For a standard 10 ft × 10 ft slab at 4 inches thick, here is the complete calculation:
Volume: 10 × 10 × (4/12) = 33.33 cubic feet
Add 10% waste: 33.33 × 1.10 = 36.67 cubic feet
80 lb bags (0.60 cu ft each): ceil(36.67 / 0.60) = ceil(61.1) = 62 bags
60 lb bags (0.45 cu ft each): ceil(36.67 / 0.45) = ceil(81.5) = 82 bags
40 lb bags (0.30 cu ft each): ceil(36.67 / 0.30) = ceil(122.2) = 123 bags
At 2026 Home Depot prices: 62 × $8.48 = $525.76 for 80 lb bags
Volume in cubic yards: 36.67 / 27 = 1.36 cu yd — this is above the ready-mix break-even point. Consider calling your local concrete plant for a quote before buying bags.
How many bags of concrete do I need for a fence post hole?+
The number of bags for a fence post hole depends on the hole diameter and depth. Here are the most common sizes:
4" post — 8" dia × 24" deep: 0.70 cu ft → 3 × 40 lb bags (or 2 × 60 lb bags)
4" post — 10" dia × 30" deep: 1.36 cu ft → 5 × 40 lb bags (or 4 × 60 lb bags)
6" post — 10" dia × 36" deep: 1.64 cu ft → 7 × 40 lb bags (or 4 × 60 lb bags)
6" post — 12" dia × 48" deep: 3.14 cu ft → 12 × 40 lb bags (or 8 × 60 lb bags)
Rule of thumb: 1–2 bags per standard 4" fence post in average soil conditions
For a quick no-mix option, use Quikrete Fast-Setting Concrete (50 lb bags) — pour dry into hole, add water, done in 20 minutes. Yield is 0.375 cu ft per 50 lb bag.
Always set post depth to at least 1/3 of total post height, or to below the frost line in your region — whichever is deeper.
What is the yield of a 60 lb bag of Quikrete in cubic feet?+
A standard 60 lb bag of Quikrete (or Sakrete) yields exactly 0.45 cubic feet of mixed concrete. This is the figure published on Quikrete product packaging and confirmed on their official product data sheets. Key facts about bag yields:
40 lb bag: 0.30 cubic feet (0.011 cubic yards)
60 lb bag: 0.45 cubic feet (0.017 cubic yards)
80 lb bag: 0.60 cubic feet (0.022 cubic yards)
50 lb Fast-Setting bag: 0.375 cubic feet
It takes 60 × 60 lb bags to make 1 cubic yard (27 cu ft ÷ 0.45 cu ft/bag = 60 bags)
It takes 45 × 80 lb bags to make 1 cubic yard
It takes 90 × 40 lb bags to make 1 cubic yard
These yields apply to standard mixes. Specialty products like Quikrete Countertop Mix may vary — always check the product data sheet.
How many bags of concrete make a cubic yard?+
One cubic yard equals 27 cubic feet. Dividing by the yield per bag:
Ready-mix comparison: $140–$200/cu yd materials + $150–$300 delivery = $290–$500 for a 1 cu yd order
Bottom line: 80 lb bags are the cheapest per cubic yard of all bag sizes. Ready-mix becomes competitive only for volumes over 1.5–2 cu yd when factoring in delivery minimums and charges.
Always add 10% waste to your bag estimate — so for 1 cu yd of finished concrete, buy 50 × 80 lb bags (45 + 10% = 49.5, rounded up to 50).
Can I use bagged concrete for a structural footing or foundation?+
Yes — bagged concrete such as Quikrete 5000 (4,000–5,000 PSI) or Quikrete Countertop Mix meets or exceeds the ACI 318-19 minimum 2,500 PSI requirement for structural concrete in residential applications. Key considerations:
IBC 2021 Section 1905 requires minimum 2,500 PSI for residential concrete — all standard 60/80 lb bags exceed this
ACI 318-19 recommends 3,000 PSI minimum for exposed foundations and footings — use Quikrete 5000 or equivalent
For footings in freeze-thaw conditions: specify 4,000 PSI minimum and air-entrained mix — most bagged mixes are not air-entrained; check the product data sheet
Structural footings also require rebar — the bagged concrete mix itself meets strength requirements, but the footing system design (size, depth, rebar) must comply with local building codes
For large footings over 1 cu yd, ready-mix is strongly preferred — ensuring consistent mix quality throughout the pour is difficult with bags
Always obtain a building permit for structural footings — inspections are required before concrete placement in most US jurisdictions
How much does a bag of concrete cost at Home Depot and Lowe's in 2026?+
Typical retail prices for bagged concrete in the USA in 2026 at major home improvement stores:
Quikrete 5000 — 40 lb bag: $4.98–$5.48 at Home Depot / Lowe's
Quikrete 5000 — 60 lb bag: $6.48–$7.48 at Home Depot / Lowe's
Quikrete 5000 — 80 lb bag: $8.28–$8.98 at Home Depot / Lowe's
Sakrete 5000 Plus — 80 lb bag: $8.49–$9.28
Quikrete Fast-Setting — 50 lb bag: $7.98–$9.48
Menards: Prices are typically 5–10% lower than Home Depot/Lowe's in Midwest markets
Buying in pallet quantities (49+ bags): Contractors can negotiate 10–20% bulk discounts at most stores — ask at the Pro Desk
Prices vary by region — Southern and Midwest markets are typically cheaper than Northeast and West Coast locations
How long does bagged concrete take to set and cure?+
Concrete sets (becomes rigid) much faster than it cures (gains full strength). Understanding the difference is critical for scheduling work:
Initial set: 1–2 hours for standard Quikrete at 70°F — this is when the surface becomes firm and finishing must be complete
Walking on slab: 24 hours minimum (standard mix), 4–6 hours for Quikrete Fast-Setting
Form removal: 24–48 hours for vertical forms; 7 days for shores under slabs
Vehicle traffic: Wait minimum 7 days before driving on a residential driveway slab
Full strength (28-day cure): 28 days — standard test age for concrete compressive strength per ASTM C39
Quikrete Fast-Setting: Sets in 20–40 minutes; walkable in 4 hours; 4,000 PSI in 28 days
Cold weather (below 50°F): Set and cure times roughly double for every 10°F drop — protect from freezing for at least 7 days
Curing is critical: Keep slab moist for 7 days minimum — use curing compound, wet burlap, or plastic sheeting. Proper curing improves 28-day strength by 30–50%.
What is the difference between Quikrete 4000 and Quikrete 5000?+
Both are standard Quikrete bagged concrete mixes, but with important differences in strength development and cost:
Quikrete 4000: Standard concrete mix — achieves 4,000 PSI at 28 days. Most economical option. Good for general purpose: slabs, walkways, patios, steps, footings.
Quikrete 5000 (High Early Strength): Achieves 5,000 PSI at 28 days AND 3,500 PSI at just 3 days — roughly double the early strength of standard mix. Ideal when faster form stripping or load application is needed.
Bag yield is identical: Both yield 0.30/0.45/0.60 cu ft per 40/60/80 lb bag — so this calculator works for both products
Price difference: Quikrete 5000 is typically $0.50–$1.00 more per bag than Quikrete 4000
Recommendation: For most DIY residential projects where you are not in a hurry to strip forms, Quikrete 4000 is adequate. For driveways, garage slabs, footings, or cold weather work, the extra early strength of Quikrete 5000 is worth the small premium.
Both products are suitable for ACI 318-19 structural concrete requirements in residential applications
Authoritative product guides, data sheets and specifications for bagged concrete in the USA.
🧱
Quikrete Product Data Sheets
Official Manufacturer
Quikrete's official product data sheets confirm yields, compressive strengths, water requirements, and application guides for all bagged concrete products — including Quikrete 5000, Fast-Setting Concrete, Countertop Mix, and specialty mixes. These are the source documents for all bag yield figures (0.30/0.45/0.60 cu ft) used in this calculator.
Sakrete's technical resource library includes product data sheets, SDS (Safety Data Sheets), and installation guides for all Sakrete bagged concrete products. Sakrete 5000 Plus and Sakrete Fast-Setting Concrete are the primary competitors to Quikrete products at Lowe's and regional home improvement stores throughout the USA.
ACI 308R "Guide to External Curing of Concrete" provides the definitive guidance on curing methods, duration, and requirements for concrete slabs and structures — including the 7-day minimum moist curing requirement referenced throughout this page. Proper curing is the single most impactful factor in the final strength and durability of any DIY concrete project.