Concrete Tube Calculator

The hollow tube concrete calculator works for pipes, rings, planters, and small culverts. Provide the outer diameter, inner diameter, and length — get cubic yards, cubic meters, weight, and bag count per piece.

Length (l)
Width (w)
Thickness or Height (h)
Quantity
 
Diagram of a rectangular concrete slab showing length, width, and thickness
Diameter (d)
Depth or Height (h)
Quantity
 
Diagram of a round concrete column or footing showing diameter and depth
Outer Diameter (d1)
Inner Diameter (d2)
Length or Height (h)
Quantity
 
Diagram of a hollow concrete tube showing outer diameter, inner diameter, and length
Curb Depth
Gutter Width
Curb Height
Flag Thickness
Length
Quantity
 
Diagram of a curb-and-gutter pour showing curb height, gutter width, flag thickness, and length
Run
Rise
Width
Platform Depth
Number of Steps
 
Diagram of concrete stairs showing rise, run, width, platform depth, and number of steps

Concrete is a material comprised of a number of coarse aggregates (particulate materials such as sand, gravel, crushed stone, and slag) bonded with cement. Cement is a substance that is used to bind materials, such as aggregate, by adhering to said materials, then hardening over time. While there are many types of cement, Portland cement is the most commonly used cement, and is an ingredient in concrete, mortar, and plasters.

Concrete can be purchased in multiple forms, including in 60 or 80-pound bags, or delivered in large amounts by specialized concrete mixer trucks. Proper mixing is essential for the production of strong, uniform concrete. It involves mixing water, aggregate, cement, and any desired additives. Production of concrete is time-sensitive, and the concrete must be placed before it hardens since it is usually prepared as a viscous fluid. Some concretes are even designed to harden more quickly for applications that require rapid set time. Alternatively, in some factory settings, concrete is mixed into dryer forms to manufacture precast concrete products such as concrete walls.

The process of concrete hardening once it has been placed is called curing, and is a slow process. It typically takes concrete around four weeks to reach over 90% of its final strength, and the strengthening can continue for up to three years. Ensuring that the concrete is damp can increase the strength of the concrete during the early stages of curing. This is achieved through techniques such as spraying concrete slabs with compounds that create a film over the concrete that retains water, as well as ponding, where concrete is submerged in water and wrapped in plastic.

02 · The method

How to calculate concrete volume

The math is geometry. The judgment is in what you measure, where you measure it, and how much overage you order. Here is how a professional estimator approaches each shape.

01

Identify the shape

Every pour reduces to a primitive: a rectangular slab, a cylinder, a hollow tube, or a stepped wedge. Decompose complex pours into primitives and sum their volumes. An L-shaped patio is two rectangles; a stoop is a slab plus stairs.

02

Measure in consistent units

Pick one unit and convert everything to it before multiplying. The most common error in DIY estimating is multiplying feet by inches and forgetting the conversion. This calculator does the conversion for you, but if you do it by hand:

1 ft = 12 in = 0.3048 m · 1 yd = 3 ft = 0.9144 m · 1 m = 100 cm
03

Apply the volume formula

Each primitive has its own formula. The most common ones for concrete work:

Slab: V = length × width × thickness
Column: V = π × (diameter / 2)² × height
Tube: V = π × ((d₁/2)² − (d₂/2)²) × length
Stairs: V = Σ(i × rise × run × width) + platform
04

Convert to your ordering unit

Ready-mix is sold by the cubic yard in the US, cubic meter in most metric markets. Bagged concrete is rated by yield in cubic feet per bag.

1 yd³ = 27 ft³ = 0.7646 m³
1 m³ = 35.31 ft³ = 1.308 yd³
05

Add waste & overage

Order more than your raw calculation. The right margin depends on conditions: 5% for tight forms with experienced crews, 10% for typical residential pours, 15% for irregular grades or trenches you have not over-excavated. Running short on a single-truck pour is far more expensive than ordering an extra quarter yard.

06

Convert volume to bags or trucks

Bag count: divide your total cubic feet by the bag yield (0.60 ft³ for an 80-lb bag). Truck count: standard ready-mix trucks hold 8–10 yd³; divide your total yd³ by 9 for a planning estimate. Always round bag counts up.

03 · Mix design

Concrete mix ratios & PSI strengths

PSI is the compressive strength concrete reaches at 28 days of cure. Pick the lowest grade that comfortably exceeds your load — stronger mixes cost more and are harder to place.

2,500 PSI
Standard Mix
cement : sand : gravel · 1 : 3 : 4

Sidewalks, residential walkways, non-load-bearing slabs, and patios with light foot traffic.

3,000 PSI
Residential
cement : sand : gravel · 1 : 2.5 : 3.5

Driveways, garage floors, residential foundations, and patios. The most common mix for home projects.

3,500 PSI
Standard Commercial
cement : sand : gravel · 1 : 2 : 3

Light commercial slabs, foundation walls, and reinforced footings supporting heavier loads.

4,000 PSI
Heavy Duty
cement : sand : gravel · 1 : 2 : 3

Commercial floors, parking lots, agricultural slabs, and structures exposed to freeze-thaw cycles.

4,500 PSI
High Strength
cement : sand : gravel · 1 : 1.5 : 2.5

Heavy industrial floors, bridge decks, and structural beams in commercial buildings.

5,000 PSI
Structural
cement : sand : gravel · 1 : 1.5 : 2

High-rise foundations, suspended slabs, and any structure requiring engineered concrete strength.

6,000 PSI
Engineered
cement : sand : gravel · Engineered

High-rise columns, marine and infrastructure construction. Requires admixtures and lab-tested mix design.

8,000 PSI
Performance
cement : sand : gravel · Engineered

Specialized structural elements where superplasticizers and silica fume are used to achieve high early strength.

04 · Reference

Bag size yields & bags-per-yard reference

Standard yields published by major US mix manufacturers. The exact figure varies a few percent by brand; always verify against the printed yield on your bag.

Bag sizeYield (ft³)Yield (m³)Bags per yd³Bags per m³Practical use
40 lb0.3000.008590118Quick repairs, post-setting, small footings.
50 lb0.3750.01067294Mid-size pads, intermediate work.
60 lb0.4500.01276078Patios under 1 yd³, fence posts, deck piers.
80 lb0.6000.01704559The standard residential bag — best $/yd³ on a small pour.
90 lb0.6750.01914052Pro-grade bag, fewer trips with the wheelbarrow.
05 · Worked examples

Common project quantities at a glance

Pre-calculated reference values for the most common residential pours. Use these to sanity-check your own numbers before you place an order.

Standard Driveway

20 ft × 10 ft × 4 in
Volume2.47 yd³
Weight~9,975 lbs
80-lb bags112
Suggested mix3,500 PSI

Patio Slab

12 ft × 12 ft × 4 in
Volume1.78 yd³
Weight~7,180 lbs
80-lb bags80
Suggested mix3,000 PSI

Footing Trench

50 ft × 16 in × 12 in
Volume2.47 yd³
Weight~9,975 lbs
80-lb bags112
Suggested mix3,500 PSI

Deck Pier

12 in dia × 48 in deep
Volume per pier0.087 yd³
Weight~352 lbs
80-lb bags / pier4
Suggested mix3,000 PSI

Garage Slab

24 ft × 24 ft × 4 in
Volume7.11 yd³
Weight~28,720 lbs
Truckload~1 ready-mix
Suggested mix3,500 PSI

Sidewalk Section

60 ft × 4 ft × 4 in
Volume2.96 yd³
Weight~11,970 lbs
80-lb bags134
Suggested mix2,500 PSI
06 · Questions

Frequently asked questions

32 answers covering volume math, mix selection, ordering, weather, and curing. Tap any question to expand.

Pick the shape you are pouring (slab, round footing, tube, curb, or stairs), measure length, width, and thickness in the same unit, then apply the volume formula for that shape. For a rectangular slab it is L × W × T. Convert the result to cubic yards by dividing cubic feet by 27, add a 10% waste margin, and round up to the nearest quarter yard for ordering.

Read the full guide →

First get the volume in cubic feet — for a slab that is length-feet × width-feet × thickness-feet (so a 4-inch slab is 0.333 ft thick). Then divide by 27 to convert to cubic yards. A 20 ft × 10 ft × 4 in driveway works out to 66.7 ft³ ÷ 27 = 2.47 cubic yards before waste.

See worked examples →

Concrete yardage is the cubic-yard figure you give the ready-mix dispatcher. Calculate raw cubic yards from your dimensions, multiply by 1.10 for waste, then round up to the supplier’s nearest delivery increment (usually a quarter yard). Below 5 yd³ expect a short-load fee; above 9 yd³ plan for a second truck.

Pricing & ordering tips →

Two shortcuts cover most residential pours. Slab: length-feet × width-feet × thickness-inches ÷ 324 = cubic yards. Round footing: diameter-inches² × depth-feet × 0.0021 = cubic yards. Both bake every conversion factor into a single number so you can size a pour in your head.

Quick formula reference →

Five steps: (1) convert thickness to feet, (2) multiply L × W × T for cubic feet, (3) divide by 27 for cubic yards, (4) multiply by 1.10 for waste, (5) round up. For a 12 × 10 ft × 4 in patio: 12 × 10 × 0.333 = 40 ft³ → 40 ÷ 27 = 1.48 yd³ → 1.48 × 1.10 = 1.63 → order 1.75 yd³.

Step-by-step worked examples →

Decide thickness first — 4 in is standard for sidewalks, patios, and light driveways; 5–6 in for heavy vehicles or garage floors. Then multiply length × width × thickness (all in feet) to get cubic feet, divide by 27 for cubic yards, and add 10% waste. Don’t forget the gravel base under the slab when planning excavation depth.

Full slab guide (rebar, base, curing) →

The volume math is exact for the geometry you enter. Real-world results vary because forms are rarely perfectly square, sub-grades settle unevenly, and concrete itself shrinks slightly as it cures. Plan to order 5–10% more than the calculated volume to absorb that variance.

A 10 ft × 10 ft × 4 in slab is 33.33 cubic feet, or 1.23 cubic yards. That is about 56 of the 80-lb bags, 74 of the 60-lb bags, or roughly half a standard ready-mix truck.

Use the slab calculator →

A standard 80-lb bag yields approximately 0.60 cubic feet of mixed concrete, so it takes 45 bags to make 1 cubic yard. The exact yield can vary by manufacturer; check the bag for the printed value.

Calculate exact bag count →

A 60-lb bag yields about 0.45 cubic feet, so 60 bags make 1 cubic yard. Mixing 60 bags by hand is slow — for anything over half a yard, consider renting a mixer or ordering ready-mix.

Calculate 60-lb bag count →

The break-even is usually around 1 cubic yard. Below that, bags are cheaper and easier to manage. Above 1 yd³, you save money and time with delivered ready-mix, and you avoid cold joints from mixing batches that cure at different rates.

How to order ready-mix →

Cement is a powder; concrete is the finished material. Cement (typically Portland) is one ingredient — about 10–15% of the mix — that bonds aggregate, sand, and water into the hardened composite called concrete.

Full breakdown of concrete ingredients →

Concrete is a composite of four ingredients: coarse aggregate (gravel or crushed stone, ~41% by volume), fine aggregate (sand, ~26%), Portland cement (~11%), and water (~16%). Most modern mixes also include small percentages of admixtures — air-entrainers, plasticizers, or retarders — to tune workability and durability.

What is concrete made of? Full guide →

Sidewalks and patios with foot traffic only: 4 inches. Driveways for cars and light trucks: 4 inches with rebar or fiber. Driveways for RVs or heavy vehicles: 5–6 inches. Garage floors: 4–6 inches. Always pour over a compacted gravel base.

Slab thickness, base prep & rebar guide →

Concrete reaches roughly 70% of its design strength in 7 days, 90% in 14 days, and full strength in 28 days. You can usually walk on a slab after 24 hours, drive on it after 7 days, and load it fully after 28.

Below 40°F (4°C), hydration slows and concrete can freeze before it cures, which destroys it. For cold pours, use heated water, accelerator admixtures, insulated blankets, and aim to keep the mix above 50°F for the first 48 hours.

Above 90°F (32°C), water evaporates from the surface faster than it can bleed up, causing plastic shrinkage cracks. Pour early morning, mist the forms, use a retarder admixture if needed, and cover the slab with wet burlap or curing blankets.

For slabs over 4 inches thick or any structural load, yes. For thin sidewalks and small pads, fiber-reinforced concrete or a #6 wire mesh is often sufficient. Rebar prevents cracks from spreading once they form — it does not prevent the cracks themselves.

Slab reinforcement & control joints →

PSI (pounds per square inch) is the compressive strength concrete reaches at 28 days. A 3,000 PSI mix can carry 3,000 lbs of compressive force per square inch before crushing. Residential work is mostly 2,500–4,000 PSI.

One cubic yard of standard concrete weighs about 4,050 lbs (1,840 kg). The density used in this calculator is 133 lb/ft³ (2,130 kg/m³), which is a typical mid-range value for normal-weight concrete.

Calculate yards & weight for your pour →

In bag form, one cubic foot runs roughly $7–$10 (using 80-lb bags). In ready-mix delivered form, expected cost is $4–$6 per cubic foot, plus delivery and short-load fees. Prices vary by region and 2026 cement market conditions.

For a homeowner, 4,000–5,000 PSI is the practical ceiling. Anything stronger requires engineered admixtures, lab testing, and curing controls that are uneconomical outside of commercial work.

Yes, for small batches under about 0.25 yd³ (roughly 11 of the 80-lb bags). Beyond that, the labor and the risk of inconsistent batches outweigh the savings. Use a mortar tub, a hoe, and add water gradually until you reach a workable but not soupy consistency.

A slump test measures concrete workability. A truncated cone of fresh concrete is inverted and lifted; the distance the mix sags down (in inches) is the slump. Most residential slabs use a 4–5 inch slump. Higher slump = wetter mix = lower final strength.

Cracks are inevitable in concrete — the goal is to control where they happen. Cut control joints at 1/4 the slab depth, spaced 24–36 times the thickness in feet (e.g. cut every 8–12 ft for a 4 in slab). Cure properly for at least 7 days and use a low water-to-cement ratio.

Curing is keeping concrete moist and at a stable temperature long enough for hydration to complete. Concrete that dries too fast loses up to 40% of its design strength. Methods include water spraying, plastic sheeting, curing compound spray, or wet burlap.

Only the amount specified on the delivery ticket, and only before the truck has discharged more than 25% of the load. Adding extra water (called "tempering") past that point reduces strength and voids most supplier warranties.

Concrete with microscopic air bubbles intentionally introduced via admixture. The bubbles give freezing water somewhere to expand into, dramatically improving freeze-thaw durability. Specify air-entrained mix for any exterior pour in a freezing climate.

No — the result is the exact theoretical volume of your shape. Add 5% for jobs with tight forms and skilled crews, 10% for typical DIY pours, and 15% for irregular grades or trenches you have not over-excavated.

Concrete contains coarse aggregate (gravel) and is poured into forms. Mortar contains only sand and is used to bond bricks, blocks, and stones. Mortar is weaker but more workable; concrete is stronger but cannot fill thin joints.

A standard truck holds 8–10 cubic yards. Divide your total volume by 9 to get a working estimate. For a half load (under 5 yd³), expect a short-load fee of $50–$150 depending on region.

Use it for estimating quantities, but not for engineering decisions. Structural pours need a stamped mix design from your concrete supplier and load calculations from a licensed engineer. This tool is a planning aid, not a substitute for engineering.

07 · Reference

Glossary of concrete terms

The vocabulary your supplier and inspector will use. Knowing these makes ordering ready-mix and reading mix tickets much faster.

Aggregate

The granular material — sand, gravel, crushed stone, or recycled concrete — that makes up roughly 60–75% of a concrete mix by volume. Coarse aggregate is over 5 mm; fine aggregate is below.

Air-entrainment

Microscopic air bubbles intentionally added to concrete via admixture. They allow freezing water room to expand, dramatically improving freeze-thaw resistance.

Admixture

Any ingredient added to concrete other than cement, water, and aggregate. Includes plasticizers, retarders, accelerators, and air-entrainers.

Bleed water

Water that rises to the surface of fresh concrete after placement. Wait for bleed water to evaporate before troweling, or you will trap weak laitance at the surface.

Compressive strength

The maximum compressive load concrete can carry before crushing, measured in PSI or MPa at 28 days of curing. The headline spec for any mix design.

Control joint

A deliberately weakened line cut into a slab so cracks form there instead of randomly across the surface. Cut to 1/4 the slab depth, before the concrete fully hardens.

Curing

The process of keeping fresh concrete moist and at a steady temperature so cement hydration can proceed. Insufficient curing is the single most common cause of weak, dusty, or cracked slabs.

Form

The temporary mold — usually wood, steel, or plastic — that holds wet concrete in shape until it sets. Forms are removed (or left as part of the structure) after the pour.

Hydration

The chemical reaction between cement and water that produces the crystalline structure giving concrete its strength. Hydration continues for years; most useful strength develops in the first 28 days.

Laitance

A weak, dusty layer of fine cement and water that rises to the top of a poured slab. It must be removed before bonding new concrete or coatings to it.

Plasticizer

An admixture that increases workability without adding water. Lets you place stiff, low water-to-cement-ratio mixes that cure stronger.

Portland cement

The standard hydraulic cement powder that, when mixed with water, binds aggregate into concrete. Named for its resemblance to Portland stone, not for the city.

PSI

Pounds per square inch — the unit used to spec concrete compressive strength. 1 PSI ≈ 0.00689 MPa.

Ready-mix

Concrete batched at a central plant and delivered by mixer truck. Standard for any pour over 1 cubic yard. Trucks hold 8–10 yd³ when full.

Rebar

Reinforcing bar — ribbed steel embedded in concrete to carry tensile loads. Concrete is strong in compression but weak in tension; rebar handles the tension side.

Retarder

An admixture that slows hydration to extend working time. Useful in hot weather or when long pours risk setting before they can be finished.

Slump

A workability measurement: how far a cone of fresh concrete sags when its mold is lifted. Most residential pours target a 4–5 inch slump.

Sub-grade

The compacted soil or gravel layer beneath a slab. A poorly prepared sub-grade is the most common reason slabs settle and crack.

Superplasticizer

A high-range plasticizer that allows extremely low water-to-cement ratios while keeping the mix flowable. Used in high-strength and self-consolidating concretes.

Water-cement ratio

The weight of water divided by the weight of cement in a mix. Lower ratios produce stronger, more durable concrete. Most structural mixes target 0.40–0.50.

Workability

How easily concrete can be placed, consolidated, and finished without segregation. Influenced by slump, aggregate gradation, and admixtures.

Yield

The volume of concrete a given amount of dry mix produces. An 80-lb bag yields about 0.60 ft³; this calculator uses standard published yields.