Concrete Curing Time Charts for Homeowners and DIYers

A concrete curing time chart can help you figure out how long it’ll take for your new driveway, sidewalk, foundation or garage floor to cure. Our charts adjust for temperature, moisture, concrete type, thickness and strength gain. 

The Basic Concrete Curing Time Chart for Beginners 

Concrete curing is the process of making sure the mix retains enough moisture and maintains the right temperature to ensure long-term durability. Drying is the process by which the mix physically dries and reaches its full strength. 

Curing Stage	Concrete Surface Strength
24-48 hours	Can support people.
7 days	Can support vehicles and equipment.
28 days	Can support heavy machinery.

Generally, concrete is safe to walk on after curing for 24-48 hours. After seven days, it should be solid enough to support machinery and equipment. It reaches its near-full strength at 28 days — what engineers consider fully cured — and is safe to use for any purpose. 

What Is the Ideal Temperature for Concrete Curing?

Temperature and humidity are two of the main factors that impact curing duration. If concrete cures too slowly or quickly, its strength will diminish — and fractures have a much higher chance of appearing sooner. 

Curing Stage	Ideal Temperature Range
7 days	68-77 degrees Fahrenheit
7-14 days	59-68 degrees Fahrenheit
14-28 days	50-59 degrees Fahrenheit

Concrete should stay at 68-77 degrees Fahrenheit within the first seven days of curing. Then, it should maintain a temperature of 59-68 degrees Fahrenheit until it reaches the 14-day mark. After that, it should stay within the 50-59 degrees Fahrenheit range until it fully cures at 28 days.

How Does Temperature Impact Concrete Curing Time?

Naturally, engineers and construction crews can plan for one circumstance and end up with another — nature doesn’t care whether they’re in the middle of curing concrete. If the temperature deviates from the optimal range, their curing duration changes.

Curing Duration	Temperature Range
3 days at most	90 degrees Fahrenheit and above
5 days	75-90 degrees Fahrenheit
7 days	60-75 degrees Fahrenheit
14 days	54-60 degrees Fahrenheit
28 days at least	45 degrees Fahrenheit and below

As you can see in this concrete curing time chart, while concrete curing only takes a few days in optimal conditions, it accelerates as temperatures rise. Unfortunately, extreme heat quickly deteriorates the mixture’s strength. Maintaining 50-80 degrees Fahrenheit is generally ideal. 

Concrete can cure in three days or less if the temperature is 90 degrees Fahrenheit and above. At 75-90 degrees Fahrenheit, it lengthens to five days. It takes seven days in the 60-75 degrees Fahrenheit range — close to optimal conditions. At 45-60 degrees Fahrenheit, it takes 14 days. When the temperature is 45 degrees Fahrenheit and below, it takes at least 28 days.

What Is the Ideal Humidity Range for Concrete Curing?

If concrete’s moisture content is too high, its curing duration lengthens. If the mixture dries out too quickly, it will become much more prone to deterioration and the surface will be littered with hairline fractures.

Curing Stage	Ideal Humidity Range
7 days	95% humidity
7-14 days	80% humidity
14-28 days	60% humidity

Concrete should maintain a specific moisture content while curing to achieve maximum strength and allow for optimal durability. As such, the humidity shouldn’t exceed 95% within the first seven days. Then, it drops to 80% until the 14-day mark and 60% until the 28-day mark. 

What happens if it rains days after pouring concrete? The droplets can damage the concrete’s surface, making it uneven and compromising the float finish — meaning it will get a pitted texture and potentially become less compact. 

While wet-curing — the process of keeping concrete wet for 28 days — exists, it requires special tools. Also, its viability depends on the concrete’s mix, treatment needs and cure compound. Besides, it’s only really used if the temperature exceeds 85 degrees Fahrenheit.

How Does Concrete Type Impact Concrete Curing Time?

Other than temperature and moisture, the other two main factors that influence concrete curing time are cement type and mixture ingredients. Depending on which one you or your contractors use, your curing time can lengthen. 

External Curing Duration	Concrete Type
7 days	Type I, ASTM C150 (standard Portland cement)
10 days	Type II, ASTM C150 (sulfate-resistant cement)
3-5 days	Type III, ASTM C150 (high-strength cement)
14 days	Type IV, ASTM C150 (low-heat Portland cement)
14-28 days	Type V, ASTM C150 (high-sulfate resistant cement)

According to the American Concrete Institute (ACI) — the ACI 308 Guide to the External Curing of Concrete, to be precise — standard Portland cement takes seven days to cure externally. Sulfate-resistant takes 10 days, high-strength takes 3-5 days, the low-heat Portland variant takes 14 days and the high-sulfate-resistant version takes 14-28 days. 

How Does Slab Thickness Impact Concrete Curing Time?

The duration of internal curing varies depending on the thickness of the pour. The mixture’s water-cement (WC) ratio is a deciding factor you should account for. Typically, it ranges between  0.4 and 0.6, depending on the type of concrete mix used. 

Slab Thickness	WC 0.4	WC 0.5	WC 0.6
4 inches	20 days	36 days	54 days
6 inches	40 days	72 days	108 days
7 inches	50 days	90 days	135 days

Slab Thickness	WC 0.4	WC 0.5	WC 0.6
4 inches	40 days	83 days	140 days
6 inches	80 days	165 days	280 days
7 inches	100 days	208 days	351 days

For the sake of simplicity, this concrete curing time chart assumes the temperature is 65 degrees Fahrenheit and the humidity is 60% — standard operating conditions. The figures represent the goal of a 4% moisture content at 75% relative humidity. 

How long does it take for four-inch concrete to cure? Upper floor slabs could take anywhere from 20-54 days in standard operating conditions. Depending on the WC ratio, on-grade slabs take longer — anywhere from 40-140 days.

How Strong Does Concrete Get As It Cures?

Most industry professionals recommend a minimum of seven days of curing. While the goal is to get to 99% compressive strength, it’s not uncommon for contractors to finish curing after one week — 65%-70% compressive strength is an acceptable range, as per ACI 301. 

Curing Stage	Strength Gain
1 day	16% of its total compressive strength
3 days	40% of its total compressive strength
7 days	65% of its total compressive strength
14 days	90% of its total compressive strength
28 days	99% of its total compressive strength

On day one, the compressive strength of concrete sits at 16%. It reaches 40% of its total strength by day three. How strong is concrete after seven days? In one week, it reaches 65%. Then, in two weeks, it gets to 90%. At 28 days, it achieves 99% of its total strength.

What days are the most critical when curing concrete? Days one through 14 are the most important because they account for 90% of its total compressive strength. Generally, the rate of strength gain slows rapidly after that — it won’t reach 100% for at least one to two years. Engineers generally use the 28-day mark as the end of the curing process for this reason.

The Time Concrete Takes to Cure Can Vary Substantially 

Concrete’s thickness, mixture type, curing compound, moisture content and water-cement ratio can impact its curing time — and that’s not mentioning the significant impact temperature, sunlight, humidity and wind can have. While these charts can help you better understand general curing times, your best bet is to consult with your contractor or do the math for your location’s conditions and mixture type.