How To Use Water Softener Size Calculator?

water softener size calculator

Are you interested in purchasing a water softener but don’t know what size to get? It can be difficult to determine which size is right for your home. Fortunately, there is a tool that can help you make the right decision, and that is a water softener size calculator.

This helpful tool considers your water usage and hardness level and determines the ideal size of water softener for your home.

With the help of the water softener size calculator, you can ensure that you get the perfect water softener to meet your needs. You can also save time & money by avoiding purchasing an oversized or undersized system. In this article, you’ll explore everything about water softener size.

Water Softener Size Calculator: What Size Water Softener Do You Need?


There are five steps to size a water softener properly. I will explain each step in-depth and provide examples so everything is simple.

1. Identify Water Hardness Level

You must determine the water’s exact hardness level. Before I dive in first, let us understand what water hardness is.

Water can be classified as soft, moderately hard, and hard. Water classification depends on its calcium carbonate concentration. In addition, water levels are measured in parts per million (ppm), mg/L, or grains per gallon (gpg).

Please Note: You can convert ppm or mg/L to gpg by dividing 17.12.

1 ppm = 1 mg/L 

1 gpg ≈ 17.12 ppm = 17.12 mg/L





Soft water

0 – 60

0 – 60

0 – 3.5

Moderately hard water

61 – 120

61 – 120

3.56 – 7.01

Hard water

121 – 180

121 – 180

7.06 – 10.51

Very hard water




It’s easy to determine what hardness level you’re confronting. You have two choices: 

  • Evaluate the water quality by selecting the calcium content. Test kits come at less than $20.
  • Test your water at an independent laboratory.
  • Seek a free quality report from a local supplier (not for private wells).

Further, pay attention to high iron levels, especially if you have well water

If the iron content of the water is 1 ppm, then the total hardness should be increased by 4 gpg. Similarly, if the manganese content is 1 ppm, then 4 gpg should be added to the total hardness.

Once you get the water hardness level, you can classify the water accordingly.

2. Estimate Daily Water Consumption

Evaluate the family’s daily water consumption. Consult your latest water bill. It will list your consumption within a specific period. You can use this number to calculate the daily average.

Suppose you do not have access to the necessary data. In that case, you can estimate the water usage in your household by multiplying the number of people living there by an approximate range of 80 to 100.

The United States Geological Survey (USGS) approximates that each person consumes a certain number of gallons of water daily. If you prefer to take extended showers, multiply that number by 100. If you are devoted to conserving water, multiply the total by 80.

Water usage = Number of people in house X 80 or 100 (accordingly)

3. Calculating Daily Softening Requirement

Now, multiply the hardness level by daily water usage. And, you’ll get the daily softening requirement.

Daily softening requirement = Hardness level (calculated in 1.) X Daily Water usage (calculated in 2. For 1 day)

Daily softening requirement is the hardness grains that a softener has to remove from your water daily.

For instance, if your hardness level is 10 gpg and daily water usage is 360 gallons per day,

Daily softening requirement = 10 gpg x 360 gallons/day = 3,600 hardness grains (per day).

Your new softener would require removing 3,600 hardness grains daily.

4. Calculating Required Total Grain Capacity

The water softening system can only purify a certain level of hardness grains before it needs to be regenerated. Once all the resin beads in the softening tank have reached saturation, they cannot absorb any more calcium or magnesium ions.

The regeneration process includes flushing out the built-up minerals and replacing them with sodium or potassium on the resin bed.

Most professionals suggest that a water softener should be recharged every 6-7 days to maintain an optimal level of softening performance, a reduced amount of wastewater, and to safeguard the head valve against damage. This will also help preserve the resin and guard it against iron and sediment deposits.

So, multiply the softening requirement of 3,600 grains by 7 days and you’ll get 25,200 grains total softening capacity.

Total Grain Capacity = Daily softening requirement (calculated in 3.) X Regeneration (7 days)

3,600 hardness grains/day x 7 days = 25,200 grains (for 7 days)

5. Considering Salt Efficiency

If you want to restore a softener’s resin bed to its full potential, you need a much larger quantity of salt. However, a partial regeneration is more economical.

For instance, 14.1 pounds of salt must completely regenerate a 33,000-grain unit. The same softener only needs 2.6 pounds of salt to produce 13,000 grains and 8.3 pounds to generate 27,600 grains.

A 33,000-grain system can extract 33,000 hardness grains from the water between two regeneration cycles, but it would require a disproportionate salt quantity to accomplish this.

It is possible to regenerate 40% of the softening bed with only one-fifth of the salt amount. At the same time, roughly 84% regeneration is achievable when three-fifths of the salt is used. This is a clever way to operate a water softener.

An increase in the salt amount will result in a rise in the softening power. But the efficiency per pound of salt will be low.

If you need a water softener that can take out 25,200 grains of hardness per week, selecting a system with a greater grain capacity – for instance, 40,000 grains – will save you a substantial amount of money on salt in the long term.

Water Softener Size Calculator: Sizing Commercial Softeners

Several factors must be considered when determining the correct size for a commercial water softener. These include water temperature, pressure, and flow rate.

Nevertheless, this sizing manual is designed for private property owners. For more complex business, I strongly suggest you contact an expert in your region.

Water Softener Size Calculator: How To Properly Size A Water Softener


When selecting a water softener, ensure the system size is adequate to decrease the sodium amount (being used) while reducing the water’s hardness. This should be based on the water’s quality and how much of it is consumed.

The first step to determining the suitable water softener size is calculating your “daily softening requirement”. This is simply the hardness your softener needs to remove daily.

Your daily relaxation time is determined by the water hardness and the amount of water you use.

Water Softener Size Calculator: Determining Softener Size For Maximum Efficiency

Before getting a water softener, it is essential to make sure that it is the appropriate size. If the system is too small, it won’t be able to reduce the water hardness adequately.

Conversely, a too-large system would be expensive and require more upkeep. So, there is a calculator for sizing water softeners to help users solve these issues.

The efficiency of your water softener determines how much salt you must buy, transport, and release into the environment. It is essential to evaluate its effectiveness in terms of salt usage. 

This will ensure you get a soft water product without too much salt. Concerning the lifespan of the water softener, it involves considerable financial outlay and ease of ownership.

The water softener size calculator calculates the size of the softener. To calculate your softener size, click here.

FAQs (Frequently Asked Questions) On Water Softener Size Calculator

1. How do I determine what size water softener I need?

Multiply the number of people in the home by the gallons of water they use daily. Then, multiply that number by the hardness of grains in water to calculate how many grains will be removed daily. You can also use water softener size calculator.

2. What is the average size of a water softener?

You can evaluate the size of a water softener based on hardness level and the number of people in your house. You can view this chart for details.

3. What size water softener for family of 5?

For a family of 5, the right size of water softener would be a 40,000-grain softener.

4. Is a larger water softener better?

If you opt for a bigger water softener, it will need regeneration less frequently. However, it will cost more initially. It is still important to select an appliance that requires regular renewal, regardless of the size.

Summary: Water Softener Size Calculator


Water softener’s size is a significant factor when purchasing a water softener. The size of the unit determines its maximum capacity and the number of softeners it can treat. If you want to keep the size small, a 30,000-grain softener should be enough. On the other hand, if you want to go big, then a 90,000-grain unit should do.

You can use a water softener size calculator to calculate its size.

Further, commercial systems must be sized to handle a certain amount of water flow and pressure. They are typically operated at full capacity for short periods, for example, during the winter or when the demand for soft water exceeds the available supply.

Before buying a commercial water softener, get a few hard numbers on your water softener system. This information will help you decide if you need a size that’s too large or too small. This numerical data will help you make an informed decision about your water softener’s size.

I hope this article on water softener size calculator sounds helpful!

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