Sourced construction math
Construction calculators that show their math.
These masonry and concrete block calculators trace every number to a named source and show it right next to the result, so the contractor pricing a job and the engineer checking the takeoff see the same evidence.
- 20×
- Spread in per-block grout figures published elsewhere
- 0.32 ft³
- Our sourced volume for one 8 in block, from CMHA TEK 09-04A
- 100%
- Of constants cited to a named ASTM, CMHA, or datasheet source
Calculators
Masonry calculators
Three sourced estimators for a block wall: how many blocks you need, how much mortar to lay them, and how much grout to fill the cells.
Why trust these numbers
Most calculators hide the constants. We put the source in your hands.
When you cannot see where a number came from, you cannot check it, and a bad constant quietly becomes a bad material order. We do the opposite.
Every constant is cited
Behind each result is a sourced value: the figure, its unit, and the standard it comes from, shown inline so you can check it.
Two methods, never blended
Where an industry table and a geometric derivation disagree, we report both and name each, instead of averaging them into a number nobody can trace.
Free, private, no sign-up
Every calculator runs in your browser. The values you enter are never stored or sent, and there is no account to create.
Who builds TrustTheCalcs → Everything here is built by Muhammad Adnan.
Try it live
Try the block fill calculator
Grout volume, cubic yards, and bag count for filling CMU walls, each with the source shown next to the number.
Order this much grout · CMHA method
2.14 yd³
57.76 ft³ · 97 × 80 lb bags
C90 minimum-thickness geometry
2.12 yd³57.17 ft³
Bare cell volume at ASTM C90 minimum face shell and web, plus your waste %. Carries no CMHA field allowance.
These two numbers land close together, and that is the point. The geometric figure uses ASTM C90 minimum face shell (1.25 in) and web (0.75 in) thicknesses, which produce the largest cell volume the standard allows: 0.302 ft³ per 8 in block. CMHA Table 2 reports 0.321 ft³ per block once field waste and overfill are included. Real units are usually made thicker than C90 minimums, so a wall built from typical block needs less than either figure. Order to the CMHA number. Why the two numbers differ. The same split, stretched across every published figure, is why masonry calculators disagree.
Bond beam grout: 0.00 ft³ (0.00 yd³)
Added on top of both figures. CMHA Table 2 excludes bond beams and other horizontal grouted courses, so this is computed separately.
Inputs used
- Block count
- 180
- Wall area
- 160 ft²
- Blocks / ft²
- 1.125
Structural safety notice
This tool provides estimates for planning only and is not a substitute for a licensed structural or civil engineer. Do not use these results for load-bearing, safety-critical, or code-compliance decisions.
How we source and correct figures: editorial policy.
Guides
Know before you order
How Much Concrete to Fill Cinder Blocks
The real per-block volume, and why published figures scatter 23-fold.
Read guide →Should You Fill Cinder Blocks With Concrete?
When filling earns its cost, when it is wasted, and what to fill with.
Read guide →Partial Grouting: Why Spacing Changes Your Order by 5.9x
Solid vs partial fill, read from the CMHA grout table.
Read guide →Mortar for Block Walls: Type N, S, M and O Compared
Which ASTM C270 type to use, what the standard specifies, and when code decides.
Read guide →Retaining Wall Cinder Blocks
Which block actually retains soil, how high you can go before a permit, common sizes and how much gravel goes behind it.
Read guide →What Drives Cinder Block Wall Cost
The four cost buckets, why labor dominates, and how to read a quote line by line.
Read guide →Why calculators disagree on the same wall
Four figures where published masonry calculators diverge, what each basis measures, and which number to order by.
Read the breakdown →Categories
What we cover
Masonry is live now. Concrete, aggregates, and structural estimators follow, each built on the same sourced-data foundation. Start with the reference data, like how much a concrete block weighs.
Masonry
LiveBlock fill, block counts, mortar, and CMU reference data.
View tools →Concrete
SoonSlabs, footings, columns, and ready-mix ordering.
Aggregates
SoonGravel, sand, and base course by volume and weight.
Structural
SoonRebar, bearing, and load-related estimators.
Price your next block wall with numbers you can defend.
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