Concrete Curing Time Calculator
How long concrete takes to cure depends on its temperature, not only the calendar. Enter the daily average temperatures for your slab and see when the 3-, 7- and 28-day milestones are really reached.
Quick answer
Concrete curing time is at least 7 days of moist curing (3 days for high-early-strength mixes, ACI 301) and 28 days to its specified strength (ACI 318 test age) at normal temperatures around 73°F. Colder concrete takes longer: at a steady 50°F, our Nurse-Saul calculation stretches 7 days to about 11.5 days and 28 days to about 46.2 days.
Published 2026-10-19 · Curing times are quoted from ACI documents (via FHWA and PCA), Quikrete and Sakrete; the temperature adjustment, tables and worked example are our own calculations with the ASTM C1074 Nurse-Saul function.
How long will my concrete take to cure?
Only the mix and the day-1 temperature are required. Blank days repeat the previous day; after the last day you enter, that temperature is held.
Days 2–14 (optional)
Result
| Milestone (source time at normal temperature) | Your concrete reaches it after |
|---|
How to use the curing time calculator
- Pick the mix. Ready-mix and high-early use ACI curing times; the bag mixes use the times printed on Quikrete's and Sakrete's data sheets.
- Enter the average concrete temperature for day 1. A cheap probe thermometer under the curing blanket beats the weather app.
- Add later days from the 10-day forecast if temperatures will change. Blank days repeat the day before.
- Keep the 14°F datum unless you want a stricter estimate. Add the pour date to get calendar dates.
- Read each milestone. The result never comes out shorter than the time the source publishes.
Assumptions & formula
- Nurse-Saul temperature-time factor (ASTM C1074): M = Σ (Ta − T0) × Δt, where Ta is the average concrete temperature in °C for the interval and T0 the datum; an interval at or below the datum adds zero.
- Datum T0 = −10°C (14°F) by default: FHWA's maturity TechBrief says this value is generally used with the Nurse-Saul equation. 0°C (32°F) is offered as a stricter choice.
- Reference temperature 23°C (73°F), the standard laboratory curing temperature for test cylinders (ASTM C192: 23.0 ± 2.0°C). Equivalent days at 73°F = M ÷ (23 − T0).
- Milestones are the published times: ACI 301 moist curing 7 days (3 for high-early), ACI 330R parking lots 3 days for cars and 7 days for other traffic, ACI 318 strength at 28 days, and the bag-mix sheet times. We treat each as "that many days at 73°F" and solve for when your concrete gets there.
- Floor: if your concrete is warmer than 73°F, the calculator still returns the published time; heat is not allowed to shorten it.
Concrete curing time by temperature
The colder the concrete, the more calendar days each "curing day" takes: at 50°F a slab needs about 11.5 days to match 7 days at 73°F, and at 40°F about 16.0 days. The table is our calculation with the Nurse-Saul function for concrete held at one constant temperature; the rate column is how many 73°F-equivalent days one calendar day is worth.
| Concrete temperature | Rate (73°F days per day) | 1 day | 3 days | 7 days | 28 days | 7 days (32°F datum) | 28 days (32°F datum) |
|---|---|---|---|---|---|---|---|
| 40°F (4°C) | 0.44 | 2.3 | 6.9 | 16.0 | 64.0 | 36.2 | 144.9 |
| 45°F (7°C) | 0.52 | 1.9 | 5.7 | 13.4 | 53.7 | 22.3 | 89.2 |
| 50°F (10°C) | 0.61 | 1.6 | 5.0 | 11.5 | 46.2 | 16.1 | 64.4 |
| 55°F (13°C) | 0.69 | 1.4 | 4.3 | 10.1 | 40.6 | 12.6 | 50.4 |
| 60°F (16°C) | 0.77 | 1.3 | 3.9 | 9.0 | 36.2 | 10.3 | 41.4 |
| 65°F (18°C) | 0.86 | 1.2 | 3.5 | 8.2 | 32.6 | 8.8 | 35.1 |
| 70°F (21°C) | 0.94 | 1.1 | 3.2 | 7.4 | 29.7 | 7.6 | 30.5 |
| 73°F (23°C) | 0.99 | 1.0 | 3.0 | 7.0 | 28.2 | 7.1 | 28.3 |
| 80°F (27°C) | 1.11 | 0.9 | 2.7 | 6.3 | 25.2 | 6.0 | 24.1 |
| 90°F (32°C) | 1.28 | 0.8 | 2.3 | 5.5 | 21.9 | 5.0 | 20.0 |
The two datum columns show how much the answer depends on one constant: near 40°F the stricter 32°F datum more than doubles the time, while above 70°F the two agree within a day. That spread is why ASTM C1074 lets you determine the datum for your own mix, and why the numbers here are planning estimates, not proof of strength.
Worked example: an October driveway
A ready-mix driveway poured in mid-October with daily average slab temperatures falling from 60°F into the mid-40s finishes its 7-day moist cure after about 11.2 days and reaches 28-day maturity after about 39.7 days (14°F datum). With the stricter 32°F datum the same temperatures give 14.4 and 47.8 days.
| Day | Average slab temperature | Rate | Running total |
|---|---|---|---|
| Day 1 | 60°F | 0.774 | 0.77 |
| Day 2 | 55°F | 0.690 | 1.46 |
| Day 3 | 52°F | 0.640 | 2.10 |
| Day 4 | 48°F | 0.572 | 2.68 |
| Day 5 | 50°F | 0.606 | 3.28 |
| Day 6 | 54°F | 0.673 | 3.96 |
| Day 7 | 56°F | 0.707 | 4.66 |
| Day 8 | 50°F | 0.606 | 5.27 |
| Day 9 | 46°F | 0.539 | 5.81 |
| Day 10 | 44°F | 0.505 | 6.31 |
| Day 11 | 48°F | 0.572 | 6.89 |
| Day 12 | 52°F | 0.640 | 7.53 |
| Day 13 | 55°F | 0.690 | 8.22 |
| Day 14 | 58°F | 0.741 | 8.96 |
After 7 calendar days this slab has only 4.66 days of 73°F curing, so the cover and water stay on until day 11.2. Car traffic under the ACI 330R 3-day rule is reasonable after about 4.5 days. After 14 days the slab has 8.96 equivalent days, and the 58°F held after day 14 carries it to the 28-day mark at day 39.7.
Bag mix curing times: what the sheets say and what that means at 60°F and 50°F
Bagged concrete makers print foot-traffic, vehicle and moist-curing times without a temperature next to them; we read them as times at normal temperature (about 70°F) and stretch them with the same maturity rate. That reading is our assumption, so treat the 60°F and 50°F columns as estimates.
| Mix | Milestone | Sheet time | At 60°F | At 50°F |
|---|---|---|---|---|
| Sakrete High-Strength | Foot traffic | 24 h | 31 h | 40 h |
| Sakrete High-Strength | Vehicle traffic | 3.0 days | 3.9 days | 5.0 days |
| Sakrete High-Strength | Keep moist | 5.0 days | 6.5 days | 8.2 days |
| Sakrete Maximizer | Foot traffic | 24 h | 31 h | 40 h |
| Sakrete Maximizer | Vehicle traffic | 2.0 days | 2.6 days | 3.3 days |
| Sakrete Maximizer | Keep moist | 5.0 days | 6.5 days | 8.2 days |
| Sakrete 5000 Plus | Foot traffic | 12 h | 15 h | 20 h |
| Sakrete 5000 Plus | Vehicle traffic | 3.0 days | 3.9 days | 5.0 days |
| Sakrete 5000 Plus | Keep moist | 5.0 days | 6.5 days | 8.2 days |
| Quikrete Concrete Mix | Curing period | 5 days (70°F+) | 7.0 days (sheet: 7 days at 50–70°F) | 8.2 days |
Quikrete is the one maker that ties its curing time to temperature (5 days at 70°F or warmer, 7 days at 50–70°F), so at 60°F the sheet's 7 days already exceeds the maturity estimate and the calculator keeps 7. Below 50°F the sheet gives no figure; there the calculator stretches the 5-day warm baseline.
Result looks wrong? Check these
- "Never reached": every day you entered is at or below the datum (14°F or 32°F), so the concrete gains nothing. Concrete that cold and still fresh can freeze; see the cold-weather guide below.
- Result is exactly 7.0 or 28.0 days: your temperatures are at or above 73°F, and the calculator does not let heat shorten the published minimum.
- Air vs concrete temperature: a covered slab can run warmer than the night air, so air temperatures make the answer longer. A probe thermometer under the cover gives a truer number.
- °C entered as °F: 15 entered as °F means 15°F (below the default datum, no gain). Convert first: °F = °C × 1.8 + 32.
- One cold day late in the list: the last value you enter is held for every day after it. Enter a warmer later day if the forecast warms up.
Curing vs drying vs hardening
Curing means keeping concrete moist and warm enough for the cement to keep hydrating; it is not the same as the surface drying. PCA's Design and Control of Concrete Mixtures notes that when moist curing stops, strength gain continues briefly and then stops once the internal relative humidity falls to about 80%. Hardening (set) happens in hours, while curing is counted in days.
When not to use this calculator
- Structural decisions such as stripping forms on elevated slabs, post-tensioning or loading a wall: use field-cured cylinders or a calibrated maturity system, as ASTM C1074 requires a strength-maturity curve for the specific mix.
- Freezing weather: at or below 40°F the governing rules are cold-weather protection rules, not curing time; see how cold you can pour concrete.
- Long-term strength in heat: the maturity method does not account for early high temperatures lowering later strength (ASTM C1074 §5.3), so warm-weather results are floored at the published times.
- Coatings and sealers: follow the coating maker's moisture or age requirement; it is a different test from strength.
Frequently asked questions
How long does concrete take to cure?
Concrete is moist-cured for at least 7 days (3 days for high-early-strength mixes) under ACI 301 and reaches the strength it was designed for at 28 days, the standard test age in ACI 318; those times assume normal temperatures. At a steady 50°F the same curing takes about 11.5 days and 28-day maturity takes about 46.2 days by the Nurse-Saul method.
How long for concrete to cure before walking on it?
Sakrete lists foot traffic after 24 hours for its High-Strength and Maximizer bag mixes and after 12 hours for 5000 Plus. Those are the makers' figures; in cool weather allow longer — at a steady 50°F, 24 hours of 73°F maturity takes about 40 h.
How long before you can drive on new concrete?
ACI 330R allows car traffic on a parking-lot slab after 3 days and all other traffic after 7 days of curing, and Sakrete lists 48–72 hours for vehicles on its bag mixes. Those times assume normal temperatures; at a steady 50°F three days of 73°F maturity takes about 5.0 days.
Is concrete fully cured in 28 days?
No, 28 days is the age at which the specified strength is tested (ACI 318), not the end of curing; concrete keeps gaining strength after 28 days while it stays moist, and the National Precast Concrete Association calls 28 days an arbitrary time frame chosen to keep testing consistent, not a property of every mix.
Does cold weather slow concrete curing?
Yes, below 50°F (10°C) early strength develops slowly and below 40°F (4°C) it is greatly retarded, according to PCA; by the Nurse-Saul method a slab held at 40°F needs about 16.0 days to match 7 days at 73°F. For pours at or below 40°F, follow the cold-weather protection rules.
Does hot weather make concrete cure faster?
Hot concrete gains early strength faster — at 90°F, 7 days of 73°F maturity takes about 5.5 days — but ASTM C1074 warns that the maturity method does not account for the effect of early-age temperature on long-term strength, so this calculator never shortens the published minimum times.
Should I water new concrete while it cures?
Yes, keep it continuously moist: Sakrete's sheets say 3–5 days and Quikrete says 5 days at 70°F or warmer, or 7 days at 50–70°F, using wet burlap, plastic sheeting or a curing compound. PCA notes strength gain stops once the concrete's internal relative humidity drops to about 80%.
What is the maturity method for concrete?
The maturity method (ASTM C1074) estimates in-place strength from the concrete's temperature history: the Nurse-Saul temperature-time factor adds up (concrete temperature − datum temperature) × time, and FHWA notes −10°C (14°F) is generally used as the datum. Accurate strength estimates need a strength-maturity curve made for your mix.
Sources
- FHWA, Guide for Curing of Portland Cement Concrete Pavements, FHWA-RD-02-099, Chapter 5 (January 2005): ACI 318, ACI 301, ACI 308 and ACI 330R curing durations; maturity for planning.
- FHWA, TechBrief: Maturity Testing for Concrete Pavement Applications (FHWA-IF-06-004, November 2005): Nurse-Saul equation and −10°C (14°F) datum.
- ASTM International, C1074-19e1 Standard Practice for Estimating Concrete Strength by the Maturity Method (2019): temperature-time factor and limitations.
- Portland Cement Association, Design and Control of Concrete Mixtures (EB001, 15th ed., 2011), Chapter 15 "Curing Concrete": early-strength temperature limits (10°C and 4°C), maturity concept, 80% internal humidity.
- American Concrete Institute, FAQ: why 28 days (ACI 318-19 §19.2.1.3).
- National Precast Concrete Association, The 28-Day Myth.
- Quikrete, Concrete Mix No. 1101 data sheet (rev. October 2022); Sakrete technical data sheets: High-Strength, Maximizer, 5000 Plus (retrieved 2026-10-18).
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Last updated 2026-10-19 · About TrueToolCalc and how we check numbers · Found an error? Use the contact page.