Convert between concrete strength notations: C grade ↔ cube strength fcu ↔ cylinder fck,cyl ↔ prism fck,prism ↔ design value fc. Ratios: fck,cyl = 0.8·fcu, fck,prism = 0.88·0.76·fcu, fc = fck,prism/1.4. Any one input produces all others.
Execution
Run this tool
Fill in the form, run the tool, and review the result in one place.
Samples
Examples that match this tool
Related
Continue with connected tools and hubs
Result
Ready for a run
Run the tool to preview files, text, structured data, or streamed output here.
Learn when to use this tool, what it supports, and how real users apply it.
Key facts
Category
Math & Numbers
Input types
select, number
Output type
json
Sample coverage
4
API ready
Yes
Overview
The Concrete Strength Grade Converter allows structural engineers and concrete technology specialists to instantly convert between standard concrete strength notations, including C grade, cube strength (fcu), cylinder strength (fck,cyl), prism strength (fck,prism), and design value (fc). By inputting any single known value, the tool automatically calculates the remaining parameters using standard conversion ratios, ensuring quick cross-referencing across different international design codes like GB 50010 and Eurocode 2.
When to use
When comparing concrete specifications between international design standards like Eurocode 2 (cylinder-based) and GB 50010 (cube/prism-based).
When calculating the design strength value (fc) from a known characteristic cube or cylinder strength for structural calculations.
When verifying if non-standard laboratory test results meet the requirements of a specified standard concrete grade.
How it works
1Select the input type corresponding to your known value: Grade (e.g., C30), Cube Strength (fcu), Cylinder Strength (fck,cyl), or Prism Strength (fck,prism).
2Enter the numeric value of the selected strength parameter and specify the desired decimal precision.
3The tool applies standard conversion formulas, including fck,cyl = 0.8 * fcu, fck,prism = 0.88 * 0.76 * fcu, and fc = fck,prism / 1.4, to output all equivalent values simultaneously.
Use cases
Cross-referencing cylinder strength requirements from Eurocode 2 with cube strength specifications in local projects.
Determining the design compressive strength (fc) for concrete structural member design calculations.
Converting experimental laboratory cylinder test results to equivalent prism and design values for compliance checks.
Examples
1. Converting Standard C30 Concrete Grade
Structural Engineer
Background
An engineer is designing a foundation using GB 50010 standards and needs the design value (fc) and prism strength for C30 concrete.
Problem
Manually calculating the prism strength and design value from the C30 grade is prone to rounding errors.
How to use
Select 'Grade' as the input type, enter '30' as the value, set decimal places to 2, and run the converter.
Outcome
The tool outputs fcu = 30.00 MPa, fck,cyl = 24.00 MPa, fck,prism = 20.06 MPa, and fc = 14.33 MPa.
2. Evaluating Non-Standard Cylinder Test Results
Quality Control Inspector
Background
A site inspection team receives cylinder test results showing a compressive strength of 25 MPa, which does not directly match a standard grade.
Problem
The inspector needs to find the equivalent cube strength and closest standard grade to verify compliance.
How to use
Select 'Cylinder Strength fck,cyl' as the input type, enter '25' as the value, and set decimal places to 2.
Outcome
FAQ
What formulas are used for the conversions?
The tool uses fck,cyl = 0.8·fcu, fck,prism = 0.88·0.76·fcu, and fc = fck,prism/1.4.
Can I input a non-standard strength value?
Yes, you can input any numeric value for cube, cylinder, or prism strength, and the tool will calculate the corresponding non-standard equivalents.
What does the C grade input represent?
The C grade represents the characteristic cube compressive strength (fcu) in MPa (e.g., entering 30 represents C30).
Which design codes align with these conversion ratios?
These ratios are commonly referenced in Chinese standard GB 50010 and related comparative structural engineering literature.
How do I adjust the precision of the output values?
You can set the Decimal Places option to any integer between 0 and 6 to control the rounding of the results.