Understanding your result
The headline is the earliest recoat time for your conditions, and the sub-line gives the touch-dry time and the estimated cure. The three figures repeat the three times.
The table shows the product’s typical data-sheet times, then the temperature, humidity and airflow factors, and the adjusted times. The factors multiply: a cold, damp, still room can stretch a 4-hour recoat to most of a day, and the table shows which of the three is doing the stretching.
Recoat times set the calendar more than the painting does. The crew schedule calculator takes the recoat wait and turns it into days on the job; the painting time calculator and the project planner build it into their day counts; and the floor finish calculator is where long recoat times matter most.
How we calculate this
The temperature rule, drying time roughly doubling for every 10 °C (18 °F) drop, is a common rule of thumb for chemical and evaporative processes, and it matches the extended times manufacturers give for cool conditions on many data sheets. The humidity factor reflects that water evaporates slower into damp air, which matters most for latex; alkyds cure by oxidation and are affected less. The cure estimate is capped at twice the data-sheet figure because the data sheets themselves rarely extend further.
The typical times by product class are listed on the drying and recoat times reference, and the drying and cure guide explains what happens in the film at each stage and why recoating early causes problems no later coat can fix.
The assumptions behind the numbers
| Product | Touch / recoat / cure at 77 °F, 50% RH | Minimum temperature |
|---|---|---|
| Interior or exterior latex | 1 h / 4 h / about 21 days | 50 °F (10 °C) |
| Latex primer | 30 min / 1 h / about 7 days | 50 °F |
| Oil or alkyd primer | 2 h / 24 h / about 7 days | 40 °F (4 °C) |
| Oil or alkyd enamel | 6 h / 24 h / about 30 days | 40 °F |
| Waterborne alkyd | 2 h / 16 h / about 21 days | 50 °F |
| Shellac primer | 15 min / 45 min / about 3 days | 40 °F |
| Oil-based polyurethane | 4 h / 24 h / about 30 days | 50 °F |
| Water-based polyurethane | 30 min / 2 h / about 21 days | 50 °F |
| Oil-based stain | 4 h / 24 h / about 3 days | 50 °F |
Typical figures from manufacturers’ technical data sheets for each product class (Sherwin-Williams, Benjamin Moore, Behr, Minwax, Zinsser), rounded. Factors for temperature, humidity and airflow are rules of thumb, not measurements.
Assumptions last reviewed October 8, 2026.
The calculator does not model film thickness (a heavy coat dries much slower), direct sun or wind on exterior work, dew, or specific products that dry faster or slower than their class. When in doubt, wait longer: a coat applied too soon wrinkles, lifts or stays soft.
Two worked examples
Latex in a cold, damp basement
55 °F, 80% humidity, a closed room.
- Temperature factor: 2^(22 ÷ 18) = 2.33
- Humidity factor: 1 + 30 ÷ 30 = 2.0; airflow 1.25
- Recoat: 4 h × 2.33 × 2.0 × 1.25 = 23 h 20 min; touch-dry 5 h 50 min; cure about 42 days
A heater and a dehumidifier would bring the recoat back toward 4 to 6 hours. In metric, at 15 °C and 70% humidity with normal airflow, the same paint recoats after about 13 h 20 min.
Alkyd enamel on a cool autumn day
60 °F, 70% humidity, normal airflow.
- Temperature factor: 2^(17 ÷ 18) = 1.92
- Humidity factor for a solvent-borne paint: 1 + 20 ÷ 30 × 0.5 = 1.33
- Recoat: 24 h × 2.57 = 61 h 35 min, about two and a half days; touch-dry 15 h 24 min
On trim this means one coat every third day, which is why waterborne alkyds, recoatable in about 16 hours at 77 °F, have taken over much interior trim work.
Where to find your inputs
Product. The class on the can; the data sheet gives its own times.
Temperature. In the room or outside, and on the surface, which can be colder: a thermometer against the wall or an infrared thermometer.
Humidity. A cheap hygrometer, or the weather report for outdoor work.
Airflow. Good with a fan or open windows; poor in a closed room or basement.
Common mistakes
- Trusting “dry in one hour”. That is touch-dry at 77 °F, not recoatable in your conditions.
- Painting below the minimum temperature. The film may never form properly.
- Painting late in the afternoon outside. Evening dew lands on soft paint.
- Recoating alkyds too soon. The second coat wrinkles the first.
- Hanging pictures on day two. Latex cures over weeks; give it time before it takes knocks.
- Heavy coats to save a coat. They dry much slower and sag.
Questions people ask
- How long before I can recoat latex paint?
- Most latex wall paints give about 4 hours at 77 °F and 50% humidity. At 55 °F and 80% humidity in a closed room, the same paint needs closer to a day, which is the case the calculator was built for.
- How long does oil-based paint take to dry?
- Alkyd enamels are typically touch-dry in about 6 hours and recoatable in about 24 at 77 °F. At 60 °F and 70% humidity, about two and a half days between coats is a safer estimate.
- What is the difference between dry, recoat and cure?
- Touch-dry is when the surface is no longer sticky. Recoatable is when the next coat will not lift or wrinkle the first. Cured is when the film has reached its full hardness and washability, usually two to four weeks for latex and about a month for alkyds; treat the surface gently until then.
- Does cold weather stop paint from drying?
- It slows it, and below a minimum it stops the film forming properly. Most latex paints need at least 50 °F (10 °C) in the air and on the surface; some are rated to 35 °F. Alkyds are usually rated to 40 °F. Below the minimum, wait or heat the room.
- Does humidity matter for oil-based paint?
- Less than for latex, because oil-based paints cure by reacting with oxygen rather than by water evaporating. The calculator applies half the humidity effect to solvent-borne products.
- Can a fan speed up drying?
- Moving air carries away evaporating water and solvent, so yes, moderately. Point it across the room, not at the wet surface, to avoid blowing dust onto it. Heat and lower humidity do more than airflow.