Air compressor fill time calculators help you determine how long it takes to pump up your air tank. Despite how insignificant this metric may seem, it is crucial to assess the efficiency and performance of your compressor.
The pump-up time describes the duration it takes for an air compressor to reach its maximum pressure (i.e., cut-out pressure) from a lower pressure level (i.e., cut-in pressure).
The air compressor fill time calculator will take into consideration numerous factors, including tank size, CFM, atmospheric pressure, and pressure difference.
Read on to learn how our air compressor fill time calculator works and the variables integrated into the formula.
How do you calculate compressor fill time?
To calculate your compressor fill time, the first option is to open the drain valve until the tank is completely empty. Next, you would use the stopwatch on your smartphone and start the compressor. The motor and pump will run until the tank is full.
However, if your air compressor has a large tank and the duty cycle is less than 50%, there is a chance that the pump will stop to cool down before it can start again. This will make it challenging to precisely measure the fill time.
Additionally, the stopwatch method may not be always possible. For instance, if you want to buy a new air compressor online, the fill time is not always mentioned.
The second option would be using our air compressor fill time calculator to estimate how long it takes for the tank to fill.
Factors that impact air compressor pump-up time
Tank size
This is perhaps the most important factor that determines pump-up time. Clearly, larger tanks will take longer to fill compared to smaller reservoirs. However, the CFM of the compressor pump also plays a crucial role.
The size of the air tank needs to be in cubic feet. Since the vast majority of air tanks mention the size in gallons, the conversion can be tricky during calculation. Luckily, our air compressor fill time calculator conducts this conversion automatically.
Compressor horsepower
Each air compressor has a specific power rating. Oftentimes, you will find this value in the horsepower (hp) unit. Compressor motors that can generate more hp generally have shorter fill times.
Pressure range
The pressure range refers to the difference between the maximum and initial pressure during operation.
As you may know, each air compressor has an initial pressure known as cut-in pressure. When the pressure gauge of the air tank reaches a specific level, the pressure switch turns on the motor. The minimal pressure varies significantly based on the power and applications of the compressor. For instance, airbrushing tools have a cut-in pressure of about 30 PSI. Conversely, sandblasting tools require a higher pressure at around 60–80 PSI.
The cut-out pressure, on the other hand, indicates a pressure level at which the compressor turns off. Generally, the maximum pressure of air compressors ranges between 110 to 180 PSI.
Cubic Feet per Minute (CFM) Rating
The CFM rating of an air compressor refers to the volume of air delivered by a compressor pump per minute. Robust air compressors have higher CFM ratings. This reflects on the speed of tank fill time.
If you’re not sure of the CFM rating of your air compressor, check out our air compressor CFM calculator.
Pump up time formula for compressor
The pump-up time formula for compressors consists of:
Tank Fill Time = Tank Volume × (cut-out pressure – cut-in pressure) / (Compressor CFM x atmospheric pressure)
Here are the details of every element of the formula:
Tank Volume – This is the volume of the reservoir (cubic feet).
Cut-out pressure – The maximum pressure that stops the compressor (PSI).
Cut-in pressure – The initial pressure that starts the compressor (PSI).
Compressor CFM – The air volume generated by the compressor (cubic feet per minute).
Atmospheric pressure – This value varies from one region to another (14.7 PSI at sea level).
How to use our air compressor fill time calculator
Our air compressor fill time calculator is user-friendly; all you need is some basic information and a few minutes to spare.
Here’s a step-by-step guide on how to use the air compressor fill time calculator:
Determine tank volume – Find the volume of the air tank in gallons (no need to convert the value to cubic feet).
Figure out compressor CFM – There are two options to figure out your compressor CFM. You can either use our CFM calculator or check out the specifications mentioned by the manufacturer. Keep in mind that CFM declines gradually with time, especially in older compressors.
Measure initial and maximal pressures – Determine the initial pressure and maximal pressure of your compressor pump. You can simply read these values on the pressure gauge when you hear the compressor pump start and stop.
Plug values into the calculator – Put the values you’ve collected into our air compressor fill time calculator.
Perform the calculation – Click on calculate to perform the calculation. The result will be in minutes. If you want to conduct another calculation, click on the reset button.
Note that the pump-up calculator provides an approximate estimation of the fill time. This is because the formula assumes that the efficiency and performance of the compressor are constant. Other factors that influence the accuracy of the result include temperature, humidity, and leaks.
Case Study – How long does a 60-gallon air compressor take to fill?
This case study provides a real-life example of how to use our air compressor fill time calculator.
Let’s consider a 60-gallon air compressor with a CFM rating of 5. The initial pressure is about 40 PSI, whereas the maximal pressure is 120 PSI.
Plugging the numbers into our fill time calculator gives us about 8.7 minutes.
If you have a more robust air compressor with a CFM of 10, the fill time is halved to 4.4 minutes.
Conclusion
The air compressor fill time calculator is a valuable tool that helps you determine the pump-up time of your compressor within a few minutes. This metric is one of the elements that provides feedback on the efficiency and performance of the compressor.
If you have any thoughts about the interface or formula of our air compressor fill time calculator, please don’t hesitate to reach out by clicking here.