Sometimes, you may need to estimate Excel’s proper or improper integrals. There is no built-in software in Excel for computing the integrals. However, you can use a dedicated add-in, **ExceLab 365 Calculus Functions**, from the **Microsoft AppSource**. The add-in provides you with a function named **QUADF** that can calculate the integrals. But unfortunately, the QUADF function doesn’t work accordingly. That’s why you won’t be able to compute the integrals with the QUADF function. We have discussed an alternative way to calculate the integrals in Excel whenever you face the problem that QUADF is not working in Excel. So, let’s get started.

## Reasons with Solution If QUADF Function Is Not Working in Excel

There may be some issues with this add-in **QUADF** function. We have tried to use the function, but it shows an error. But we have come up with an alternative solution to solve the integral.

### Possible Reasons Why QUADF Is Not Working in Excel

We have tried to find out the reason that the **QUADF** function is not working in your Excel. The possible reason behind this is discussed below.

- Suppose the
**QUADF**function is disabled in Excel. That means if you don’t install the**ExceLab 365 Calculus Functions Add-in**in your Excel application. - If you failed to define the initial value. In that case, you’ll get
**#NUM! Error**. - The worst situation that you may face is that the function can show you
**#VALUE! Error**for several reasons. For example, it is not working properly in Excel 365 version.

For your clarification, we have taken an integral function to apply the **QUADF **function.

The integral function is

`∫(x²+2x+3)dx`

In this function, we set the lower limit **1** and the upper limit **4**.

Now, for calculating the integral, we need to calculate the function value with a random **x1** value. For our case, we use **1** for the **x1** value. And we get the function value **6 **for that value.

At this moment, we use the **QUADF** function for computing the integrals. In cell **C6** we entered the below formula.

`=QUADF(C5,X1,1,4)`

Here, the **C5** is the function value** f**, and **X1** is the value for what we have got the function value. **1** is the lower limit and **4** is the upper limit.

Eventually, hit **ENTER**.

Oops! We have got a**#VALUE! Error **after using the **QUADF** function.

**Read More: How to Make First Derivative Graph on Excel**

#### A Suitable Solution to Fix the Issue Using Mid Point Rule

It is clear that the **QUADF** function is not working properly. We have made an alternative but effective solution to calculate the integrals which is the **MidPoint Rule** also known as **Simpson’s Rule**. More importantly, you don’t need to add any add-ins to your Excel application.

The value of the integral is **45** when we estimate it manually. Now, we will try to show the same integral value for ensuring our method.

- Firstly, in cell
**C17**enter the formula.

`=(4-1)/10`

Here, **4** and **1** represent the **b** and **a** respectively which are the **upper bound** and the **lower bound** of the integral. And **10** is the number of steps (**n Value**).

- Now, enter the formula given below in cell
**C18**.

`=C17/2`

Here, cell **C17** represents the value of **dx**.

- At this time, insert the following formula in cell
**C5**.

`=1+C18`

Here, cell **C18** indicates the value of **dx/2**.

- Consequently, in cell
**C6**insert the formula.

`=C5+$C$17`

Afterward, you will have the **x Value** for the **2nd **step.

- Eventually, press
**ENTER**and drag down the**Fill Handle**tool for the other cells.

As a result, you get the following output for the **x Value**.

- Following that, we will calculate the
**f(x)**value. For this operation, go to cell**D5**and enter the formula.

`=C5^2+2*C5+3`

Here, cell **C5** refers to the **x Value**.

Subsequently, drag it down for the other cells to get the below output.

- Now, we will calculate the individual integral values for each step. To do this, go to cell
**E5**and enter the formula.

`=D5*$C$17`

Here, cell **D5** indicates the **f(x) Value**.

Consequently, press **ENTER** and drag it down to get the result below.

Lastly, we use the **SUM function** to evaluate the sum of the integral values. For this, go to cell **E15** and insert the formula.

`=SUM(E5:E14)`

It will calculate the arithmetic sum of all the **10** integral values.

- Hit
**ENTER**and drag the same formula for other cells.

Hurray! As you can see, we get the **Final Integral Value** of **44.9775** which is so close to our desired result of **45**.

So, we can say that this **Mid Point Rule** helps you out on the issue of *QUADF **not working*.

**Read More: How to Do Integration in Excel**

## Practice Section

We have provided a practice section on each sheet on the right side for your practice. Please do it by yourself.

**Download Practice Workbook**

## Conclusion

That’s all about today’s session. And these are some reasons and solutions why **QUADF **is not working in Excel. Please let us know in the comments section if you have any questions or suggestions. For a better understanding, please download the practice sheet. Thanks for your patience in reading this article.