Convert concrete PSI to MPa, kg/cm², flexural strength (MOR), split tensile strength, and modulus of elasticity — instantly. Includes ACI 318 minimum PSI requirements for every US project type.
Enter your concrete compressive strength in PSI (or MPa) to get all strength conversions instantly.
Common US values: 2,500 · 3,000 · 3,500 · 4,000 · 5,000 · 6,000 PSI
Affects modulus of elasticity and strength correlation factors.
Concrete PSI (pounds per square inch) is the standard US measurement of concrete compressive strength — the maximum load per unit area a concrete sample can withstand before crushing. In the United States, compressive strength is tested using the ASTM C39 Standard Test Method, which involves crushing a 6×12-inch cylindrical concrete specimen at 28 days after casting. The result is reported in PSI and becomes the basis for all structural design calculations under ACI 318 Building Code.
2,500 PSI — Light-use, non-structural fill | 3,000 PSI — Residential slabs, sidewalks, foundations | 3,500 PSI — Driveways, garages | 4,000 PSI — Structural beams, columns, elevated slabs | 5,000 PSI — High-strength, freeze-thaw, prestressed | 6,000–8,000 PSI — Commercial, bridges, parking structures. For detailed ACI design requirements, see ACI 318 at the American Concrete Institute.
The standard US method for measuring concrete compressive strength. A 6-inch diameter × 12-inch tall cylinder is cast from fresh concrete, cured 28 days, then crushed in a hydraulic press. The failure load divided by the cross-sectional area gives the PSI value. Ready-mix suppliers provide certified cylinder break reports for every commercial pour.
PSI is the US-exclusive unit; MPa is used internationally and in Canada, UK, and Australia. The exact conversion is 1 MPa = 145.038 PSI. A common US residential mix of 4,000 PSI = 27.6 MPa. Engineers working on international projects or using European specifications must always convert. ASTM C39 (USA) uses PSI; EN 206 (Europe) uses MPa on cube specimens.
For pavements and slabs, the flexural strength (fr) is often more relevant than compressive strength. Per ACI 318, fr = 7.5 × √f'c (in PSI). A 4,000 PSI mix has a flexural strength of approximately 474 PSI (3.27 MPa). Pavement engineers use the modulus of rupture (MOR) measured per ASTM C78 beam test.
All strength conversions used by this concrete PSI to strength calculator are based on published ASTM and ACI equations. The modulus of elasticity formula is the most widely used derived property in US structural engineering, applicable to any normal-weight concrete with unit weight near 145 lb/ft³.
The design PSI rating (f'c) of any concrete mix — whether Quikrete, Sakrete, or ready-mix — is always the 28-day compressive strength measured on a 6×12 inch cylinder per ASTM C39. At 3 days, concrete typically has only 50% of its rated PSI. At 7 days, approximately 70%. Never base structural load decisions on concrete strength before the full 28-day cure unless accelerated testing (ASTM C684) confirms early strength.
Full reference table covering all common US concrete grades from 2,000 to 10,000 PSI with conversions to MPa, kg/cm², flexural strength (MOR), split tensile, and modulus of elasticity per ACI 318 and ASTM C39.
| PSI (f'c) | MPa | kg/cm² | Flexural fr (PSI) | Modulus Ec (psi) | Typical US Use |
|---|---|---|---|---|---|
| 2,000 PSI | 13.8 MPa | 140.6 kg/cm² | 335 PSI | 2,549,510 PSI | Mass fill, non-structural |
| 2,500 PSI | 17.2 MPa | 175.8 kg/cm² | 375 PSI | 2,850,000 PSI | Light residential |
| 3,000 PSI | 20.7 MPa | 210.9 kg/cm² | 411 PSI | 3,122,000 PSI | Slabs, sidewalks, foundations |
| 3,500 PSI | 24.1 MPa | 246.1 kg/cm² | 444 PSI | 3,370,000 PSI | Driveways, garages |
| 4,000 PSI | 27.6 MPa | 281.2 kg/cm² | 474 PSI | 3,605,000 PSI | Structural beams & columns |
| 4,500 PSI | 31.0 MPa | 316.4 kg/cm² | 503 PSI | 3,824,000 PSI | Freeze-thaw exposure |
| 5,000 PSI | 34.5 MPa | 351.5 kg/cm² | 530 PSI | 4,031,000 PSI | High strength, prestressed |
| 6,000 PSI | 41.4 MPa | 421.8 kg/cm² | 581 PSI | 4,415,000 PSI | Commercial, parking structures |
| 8,000 PSI | 55.2 MPa | 562.4 kg/cm² | 671 PSI | 5,099,000 PSI | High-rise, bridge decks |
| 10,000 PSI | 68.9 MPa | 703.1 kg/cm² | 750 PSI | 5,700,000 PSI | Ultra-high performance |
Selecting the correct concrete PSI rating for your project is a code requirement under ACI 318 Building Code and local jurisdiction requirements across all 50 US states. Using too low a PSI causes structural failure; using unnecessarily high PSI wastes money. The table below summarizes minimum PSI requirements by project type based on ACI 318-19 and general US construction practice.
Most US residential concrete — slabs, patios, walkways, foundations — requires 3,000 PSI minimum per ACI 332 (Residential Code). Driveways and garages should use 3,500–4,000 PSI. In states with freeze-thaw cycles (MN, WI, NY, MI, CO), the minimum is 4,500 PSI with air entrainment per Heidelberg Materials and ACI 318 Table 19.3.
ACI 318 requires a minimum of f'c = 2,500 PSI for structural concrete, but in practice US commercial structures use 4,000–6,000 PSI for beams, columns, elevated decks, and shear walls. High-rise construction in cities like New York, Chicago, and Houston routinely specifies 8,000–12,000 PSI for lower floor columns.
Bridges, parking structures, airport pavements, and marine structures use 5,000–8,000 PSI concrete with strict durability requirements. Prestressed concrete per AASHTO and ACI 318 requires a minimum of 5,000 PSI at transfer and 6,000 PSI at 28 days. Ultra-high-performance concrete (UHPC) used in US bridge decks exceeds 20,000 PSI.
Official standards and industry references used in this concrete PSI to strength calculator.
ACI 318 is the primary US structural concrete building code, defining minimum PSI requirements, strength formulas, and durability requirements for all concrete construction across the United States.
ACI 318 StandardASTM C39 is the Standard Test Method for compressive strength of cylindrical concrete specimens — the definitive method for measuring concrete PSI strength in the USA, used on every commercial and testing lab pour.
ASTM C39 StandardThe PCA publishes free technical guides on concrete strength, PSI mix design, durability, and US construction best practices — including detailed tables of concrete properties by PSI grade for all US project types.
PCA Resources