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Concrete Maturity Method Calculator (Nurse-Saul)

Compute a concrete pour's maturity index from its average curing temperature and elapsed time, per ASTM C1074.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-27 · v1.1.0

Market
Imperial · sales tax

Maturity index

5040 °C-hours

Check your inputs

This uses a single average temperature for simplicity — a real maturity study integrates continuously logged temperature data over time, which is more accurate when temperature varies significantly during curing (e.g. cold nights, hot days).

Elapsed time
7 days
Datum temperature used
14 °F

Running these inputs gives 5040 °C-hours as the maturity index. Expect some drift against the real job; the calculation is solid but conditions on site are not. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • ASTM C1074 Nurse-Saul maturity function: M(t) = Σ(T − T0) × Δt, where T is the concrete temperature, T0 is the datum temperature (standard default −10°C / 14°F), and Δt is the elapsed time interval

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

What is the maturity method used for?
It correlates a concrete's temperature history with its strength development, letting field crews estimate in-place strength (for formwork stripping or post-tensioning timing) without waiting for a lab-cured cylinder break.
Why is the datum temperature negative?
ASTM C1074's standard −10°C (14°F) datum reflects that cement hydration (and therefore strength gain) continues at a very slow rate even somewhat below freezing, not stopping abruptly at 0°C.
Can I convert this maturity index directly to compressive strength?
Not without a mix-specific strength-maturity calibration curve, developed by testing cylinders of your actual mix at several ages and correlating their strength to their maturity index — this calculator only gives you the maturity index itself.