Ready Mix Calculator Bags Guide

Convert a ready-mix yardage estimate into 40, 60, or 80 lb bag counts, then compare bag mixing with truck delivery for your project.

Use the Ready-Mix vs Bags Calculator for the decision and the Concrete Bag Calculator for bag counts. If a supplier quote is involved, compare it in the Concrete Quote Reviewer.

Keep a supplier's material-and-delivery quote separate from an installed bid that also includes preparation, placement, finishing, and cleanup.

Quick answer

Use these common conversions:

These use common yields of 0.60 ft3, 0.45 ft3, and 0.30 ft3. Confirm the yield printed on the exact bag before buying.

Delivery access, short-load fees, truck timing, and jobsite safety should be confirmed with a qualified local professional or supplier when needed.

When bags stop making sense

Use the Ready-Mix vs Bags Cost Guide to compare material, labor, delivery, and finish timing.

For a side-by-side buying decision, use the Ready-Mix vs Bags Cost Comparison to line up bag labor, short-load fees, delivery, and timing risk before requesting a supplier quote.

Ready-mix quote lines to check

For small loads, see Minimum Concrete Delivery Order and Concrete Short Load Fee.

Example cost crossover

Compare crew size, access, mixer capacity, delivery windows, and whether the concrete must be placed continuously before choosing either buying path.

Decision workflow

Start with the volume, then move through the buying constraints in order. The math can say 45 bags, but the site may still favor delivery if the concrete must be placed quickly or finished by a small crew.

For homeowners, the hidden cost is often time. A small slab can be cheap in bags but hard to finish well if mixing drags on. For contractors, the hidden cost is often schedule risk: crew time, rework, wait fees, or a cold joint can cost more than the material difference.

Supplier call script

Use this wording when a calculator result is near the bags-versus-ready-mix breakpoint:

The project is ___ yd3 after waste. If I order ready-mix, what is the delivered
total after minimum yards, delivery, short-load, fuel, tax, washout, and wait
time? If I use bags, I expect about ___ 80 lb bags. Is truck chute access good,
or should I price buggy, pump, or wheelbarrow placement?

Then compare the answer with bag price, mixer rental, helper labor, store trips, pallet delivery, and cleanup. A ready-mix quote that looks high may still be the lower-risk choice when the bag count is large.

What the bag conversion does not include

The conversion table does not include reinforcement, forms, gravel base, vapor barrier, control joints, finishing tools, curing compound, disposal, or permit requirements. It also does not prove that the slab thickness is appropriate. Use it as a buying check after dimensions and scope are already reasonable.

Final comparison checklist

When the bag count and ready-mix quote are close, choose based on the complete placement plan rather than the lowest material line. Write down the usable volume, waste factor, bag yield, expected bag count, ready-mix billable yards, minimum order, delivery fee, short-load fee, access method, wait-time rule, and cleanup responsibility. Then compare the total job effort.

A bag path needs pickup or delivery, storage, lifting, water, mixer cycles, helpers, and enough time to place and finish the concrete. A ready-mix path needs site readiness, truck access, chute reach, washout, and someone who can make field decisions if the truck is early, late, or the forms are not ready. Neither path is automatically cheaper until those constraints are visible.

FAQ

How many 80 lb bags equal one yard of ready-mix?

About 45 common 80 lb bags equal one cubic yard, because one yard is 27 ft3 and each bag yields about 0.60 ft3.

How many 60 lb bags equal one yard?

About 60 common 60 lb bags equal one cubic yard when each bag yields about 0.45 ft3.

How many 40 lb bags equal one yard?

About 90 common 40 lb bags equal one cubic yard when each bag yields about 0.30 ft3.

Is ready-mix cheaper than bags?

It depends on bag price, delivery, short-load fees, access, mixer rental, labor, and whether the pour must be placed continuously.

Should I use ready-mix for two yards?

Two yards is about 90 80 lb bags, so ready-mix usually deserves a quote unless truck access, minimum fees, or site constraints make bags more practical.

Next step

Compare both paths in the Ready-Mix vs Bags Calculator, then review any supplier bid in the Concrete Quote Reviewer. Contractors can package the final material path with the Concrete Proposal Kit.