Live net-vs-order board so form geometry never pretends to be the truck ticket you should call in.
Educational DIY volume sketch. Not structural engineering, mix design, or building-code approval. See disclaimers.
By Ahmet C. Toplutaş·Site owner & editor · Home tools
Last updated May 21, 2026 · Reviewed May 21, 2026 · Planning estimates only - not tax, medical, or investment advice
01
Concrete planning has two volumes that people mix up. Net pour is pure geometry: the space inside the forms. Order volume is net plus a waste allowance for spillage, over-excavation, and uneven subgrade. Ready-mix tickets and bag counts should track the order side, not the optimistic net alone.
This page’s framing is net vs order, with a bag ladder on order cubic feet. It is DIY unit literacy, not a stamped structural design or mix recipe.
Not engineering advice. Load-bearing footings, slabs on grade with vehicles, and anything under inspection need licensed design and local code. See our disclaimers.
Decision framing: “Am I quoting the form geometry, or the volume I should actually order?”
02
Shape chips pick the form story. Slab and footing use length × width × thickness. Column uses the same rectangular box for a rect pier. Cylinder uses πr²h for tube forms (Sonotube-style). Pick the chip that matches what you are filling, not a neighboring DIY calculator’s area story.
Load Patio slab, then Footing run. Watch net and order jump with geometry while waste % stays readable as a separate peel.
Keep waste at 10%. Flip Patio slab → Drive strip. Watch only net and order move. That is the product.
03
The unique affordance is the bag ladder: approximate bag counts for common sizes, rounded up from order cubic feet using typical cured yields (for example about 0.60 ft³ per common 80 lb bag). Brand labels differ. Confirm yield before you buy a pallet.
That is a different job from a paint coverage coats stack or a fertility day-14 myth peel. Here the literacy beat is yards versus bags on the same order volume.
04
Imperial mode expects length/width/height in feet and thickness/diameter in inches, matching how most patio notes are written. Metric mode uses meters for length dimensions and centimeters for thickness/diameter. The twin readout always shows yd³ and m³ so a supplier ticket in either unit stays comparable.
05
Convert inputs to meters, compute geometric volume, convert to yd³/ft³, apply waste, then estimate bags from order ft³.
Waste chips (5%, 10%, 15%) are planning defaults, not a site survey. Rough forms may need more; tidy pads may need less.
06
After pour-volume literacy, hand off for floor area, paint coverage, landscape bulk, or site legal boundaries.
07
Scenario A: Patio slab. 10×8 ft at 4 in with 10% waste. Net sits under a third of a yard; order and the 80 lb bag count show why “round up” matters on small pours.
Raise waste from 10% to 15% without changing dimensions. Watch only the order column and bag ladder move.
Scenario B: Drive strip. Thicker slab, larger footprint. Order volume climbs into ready-mix conversation territory; bags become a labor story as much as a cost story.
Scenario C: Footing run. Long, narrow, thick. Geometry literacy for strip footings; still not a substitute for engineer-sized frost depth or rebar.
Scenario D: Sonotube. Cylinder math for a 12 in tube, 4 ft tall. Lower waste chip is common for contained forms; still round bags up.
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Stop here for volume and bag literacy. Hand off for floor finishes, paint, landscape bulk, or engineered design.
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No. It is an educational volume sketch for DIY planning (geometry plus an optional waste allowance and bag ladder). It does not size reinforcement, specify psi, or replace a licensed engineer, building official, or supplier ticket for load-bearing work.
Net is the geometric pour volume from your dimensions. Order volume multiplies net by (1 + waste%). Waste covers over-excavation, spillage, and uneven subgrade. Ready-mix yards are usually ordered on the order side, rounded up to what the plant will deliver.
Bag counts use approximate cured yields per bag (for example about 0.60 ft³ for a common 80 lb bag) applied to order volume, then rounded up. Real bags and mixes vary by brand. Confirm yield on the bag label before you buy.
Slab and footing use length × width × thickness. Column uses the same rectangular box math for a rect pier. Cylinder uses πr²h for tube forms (Sonotube-style). Pick the shape that matches the form you are filling.
In imperial mode this panel expects length/width (or height) in feet and thickness/diameter in inches, which matches how most patio and slab notes are written. Metric mode uses meters for length/width/height and centimeters for thickness/diameter.
Many DIY pours use about 5–10%. Rough subgrade, complex forms, or first-time pours may warrant more. This tool does not know your site; it only applies the percent you choose.
Use it to sanity-check dimensions and unit literacy (yd³ vs bags). Final orders should match the supplier’s units and your engineer’s or inspector’s requirements.
LIVE POUR SKETCH
Net vs order →Scene preset
Shape
NET VS ORDER
Net pour
0.99 yd³
0.755 m³
Order (+10%)
1.09 yd³
0.831 m³
BAG LADDER
Rounded up on order volume (29.3 ft³). Confirm bag yield on the label.
Updates as you type. Share writes the URL; typing does not. Educational DIY sketch only.
Order volume
1.09 yd³
Slab pour sketch · net 0.99 yd³ · 0.831 m³ ordered
Order volume is net pour times your waste percent. Ready-mix tickets and bag counts should track the order side. This is geometry literacy, not a stamped structural design.
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