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Jhon W

Jhon W is the founder and editor of Concrete Calculator Free. He builds every calculator on the site and checks each figure it uses against a published source. Email: jhonw2241@gmail.com

What Jhon works on

Jhon builds and maintains the 21 calculators on the site: concrete for slabs, footings, posts and tube forms; gravel, sand and asphalt; block, brick, mortar, pavers and retaining walls; rebar; and the cost calculators. He also writes the guides on the blog.

How each calculator is checked

  • Every bag yield, weight and size comes from a manufacturer's data sheet, a government design manual or an industry association's technical note, and the source is named on the page that uses it.
  • The formula and a worked example are on every calculator page, so each result can be checked by hand.
  • More than 200 automated checks run the calculators with known inputs and compare the results with figures worked out by hand.
  • Each calculator is tested in English and Spanish, at phone and desktop screen sizes, before it is published.
  • Pages are reviewed when a source is revised. Last review: 8 October 2026.

Sources used on this site

The calculators on this site use these published sources:

  1. Quikrete, Concrete Mix No. 1101: data sheet and product page. Bag yields: 0.30 ft³ (40 lb), 0.375 ft³ (50 lb), 0.45 ft³ (60 lb) and 0.60 ft³ (80 lb); bags per pallet: 80, 56 and 42.
  2. Quikrete, Fast-Setting Concrete Mix No. 1004: data sheet. Yields of the 50 lb and 60 lb fast-setting bags.
  3. Quikrete, How to set posts in concrete: instructions. Hole width of three times the post and hole depth of one third to one half of the post above ground, plus 6 in of gravel.
  4. Quikrete, Mortar Mix No. 1102: data sheet (revised November 2020). One 80 lb bag lays up to 37 standard bricks or 13 standard 8 × 8 × 16 in blocks.
  5. Federal Highway Administration (FHWA), Report FHWA-HRT-05-057. Normal-weight concrete: 145 lb per cubic foot (1.96 tons per cubic yard).
  6. Washington State Department of Transportation, Design Manual M 22-01, Exhibits 620-1 and 620-2. Dry weights in tons per cubic yard of gravel, crushed stone, ballast, sand and hot mix asphalt.
  7. Minnesota Pollution Control Agency, Minnesota Stormwater Manual. Loose sand: 1.4 tons per cubic yard.
  8. California Department of Transportation (Caltrans), Bridge Design Details 13.1 (September 2025), ASTM reinforcing bar table. Diameter and weight per foot of bar sizes #3 to #8.
  9. Brick Industry Association, Technical Note 10. Bricks per square foot by brick size, mortar per 1,000 bricks, 5% brick waste and 15 to 25% extra mortar.
  10. Concrete Masonry & Hardscapes Association, CMU-TEC-001-23. Block sizes and 119 blocks per 100 square feet including 5% waste.
  11. Concrete Masonry & Hardscapes Association, TEK 04-02A, Concrete Masonry Materials. One 70 lb bag of masonry cement for about 30 blocks; one ton of sand for about 240 blocks.
  12. Concrete Masonry & Hardscapes Association, SRW-TEC-005-09, Guide to Segmental Retaining Walls. Leveling pad and drainage gravel sizes behind the wall.
  13. Concrete Masonry & Hardscapes Association, PAV-TEC-002-22, Construction of Interlocking Concrete Pavements. Base depth of 4 in for patios and 6 in for driveways, and a 1 in bedding sand layer.
  14. Sonoco, Sonotube concrete forms brochure. Sonotube is a registered trademark of Sonoco.
  15. National Institute of Standards and Technology (NIST), PS 20-25, American Softwood Lumber Standard. A nominal 4 × 4 post measures 3 1/2 in.
  16. Anchorage Sand & Gravel, 3/8 in minus concrete pea gravel: product data. Pea gravel: 1.3 tons per cubic yard.
  17. Techniseal, Alliance Gator, Sakrete and SEK-Surebond, Polymeric sand technical data sheets (EZSAND, Gator Maxx G2, Paver Set, PolySweep). Coverage of one bag of polymeric sand by joint width.

Contact

To report a wrong result, suggest a calculator or ask about a source, email Jhon at jhonw2241@gmail.com.