Calculate area for rooms, yards, and outdoor spaces. Add multiple areas together. Includes triangle and circle shapes.
Every concrete project depends on hitting the right compressive strength. The difference between 2,500 PSI and 3,500 PSI is the difference between a slab that lasts decades and one that cracks within years.
ASTM C94/C94M sets how ready-mixed concrete is batched, measured and delivered, but it does not fix one default strength for every pour. Quality requirements are either those stated in the specification or those ordered by the buyer, and where the two differ, it is the purchaser's own specification that governs.
-- ASTM International, C94/C94M Standard Specification for Ready-Mixed Concrete
That one line is why the number on your delivery ticket matters more than any blanket figure you read online. C94/C94M is an end-result specification. It tells the plant what to prove, not what to pour. You name the strength when you order, and for most residential work that lands between 3,000 and 4,000 psi at 28 days. A plant will batch weaker if nobody says otherwise.
Source: ASTM C94/C94M, explained in NRMCA Concrete in Practice -- nrmca.org
The National Ready Mixed Concrete Association publishes Concrete in Practice, a free series of one-page technical sheets written in a plain what, why and how format for contractors and owners.
-- National Ready Mixed Concrete Association, Concrete in Practice series
Those sheets are the fastest sanity check we know of when a contractor tells you something that sounds off. Short, free, and written by the people who actually batch the material.
Use this free flooring calculator to find out exactly how many boxes of flooring you need for any room -- with the right waste factor built in. Enter your room dimensions, select your flooring type, and choose your box coverage. The calculator handles the waste factor automatically: 10% for vinyl plank and laminate, 15% for hardwood, and up to 20% for diagonal or herringbone patterns. Add multiple rooms and see the combined total in one step.
| Flooring Type | Material Cost | Installed Cost | Lifespan | Waste Factor |
|---|---|---|---|---|
| LVP (Vinyl Plank) | $2-$7/sq ft | $4-$10/sq ft | 15-25 years | 10% |
| Laminate | $1-$5/sq ft | $3-$8/sq ft | 10-25 years | 10% |
| Solid hardwood | $5-$15/sq ft | $8-$20/sq ft | 50-100 years | 15% |
| Ceramic tile | $1-$10/sq ft | $5-$15/sq ft | 50+ years | 10-15% |
| Carpet | $1-$8/sq ft | $3-$12/sq ft | 5-15 years | 10% |
LVP has become the most popular choice in new construction and remodels since 2020 because it is waterproof, durable, and floats over subfloors without glue or nails. Solid hardwood adds more home resale value per square foot than any other flooring type but costs 3-5× more to install.
Let flooring acclimate in the room for 24-72 hours before installation. Hardwood needs 72 hours minimum. LVP needs 24 hours. This allows the material to adjust to room temperature and humidity -- skip this step and the floor will expand or contract after installation, causing gaps or buckling.
LVP and laminate require a subfloor flat to within 3/16 inch over 10 feet. Use a long level or straight board to find high and low spots. Grind high spots with a belt sander. Fill low spots with floor leveling compound. An unlevel subfloor causes floating floors to "bounce" and click joints to separate.
All floating floors (LVP, laminate) must have a 1/4-inch expansion gap around all walls, cabinets, and obstacles. Use spacers while laying. Cover gaps with baseboards and quarter-round molding. Skip the gap and the floor will buckle in summer when it expands from heat and humidity changes.
Always pull planks from multiple boxes simultaneously as you install. Color and shading vary slightly between production runs -- even within the same order. Mixing boxes randomizes any variation so it blends in naturally. Installing one full box at a time creates visible banding lines across the floor.
Multiply room length by room width to get square footage. Then add the waste factor for your flooring type: 10% for LVP or laminate, 15% for hardwood, 10-15% for tile. For multiple rooms, calculate each separately and add them together. Our calculator above handles this automatically.
A 12x12 room is 144 square feet. With 10% waste, you need 158 square feet of material. At 25 sq ft per box (typical LVP), that's 7 boxes. Check your specific product's box yield -- it varies by manufacturer.
A 15x20 room is 300 square feet. With 10% waste for LVP or laminate, order 330 square feet total. That's about 14 boxes at 25 sq ft/box. For hardwood at 15% waste, order 345 sq ft -- about 18 boxes at 20 sq ft/box.
Divide the L-shape into two rectangles. Calculate each rectangle separately (length x width), then add the totals. Our calculator's Add Another Room button handles this -- enter each rectangle separately and the total updates automatically.
12 x 8 = 96 square feet. With 10% waste for LVP, you need 106 square feet or 5 boxes at 25 sq ft/box. For carpet, that's about 12 square yards (96 ÷ 9 = 10.7, plus waste).
Divide square feet by 9 to get square yards. A 12x15 room is 180 sq ft ÷ 9 = 20 square yards. Then add 10% waste = 22 square yards of carpet to order.
Buy 10% extra for LVP, laminate, and straight-set tile. Buy 15% extra for hardwood and diagonal tile. Buy 20% extra for herringbone or complex patterns. Always keep 2-3 boxes of leftovers for future repairs -- box dye lots can change.
Last updated . Formulas reviewed by Joe R., Masonry Specialist, and Elena S., Civil Engineer (PE). Spotted a number that looks wrong? Report a Data Error and we will re-verify it against the source.