# interpolation function?

#### UncleBose

##### New Member
Hello all.
I'd like some function to return a value from in between known values in a range.

<pre> A B C
1 114 90 175 <---user entry
2 123 98 135 <---returned value
3 132 105
4 148 119
5 165 129
6 181 138
7 198 146
8 220 155
9 242 159
10 275 164
11 319 167</pre>

These relationships are nonlinear. Column B is dependent. I want to be able to enter any number within the A range into C1, and return a properly interpolated value from within the B range in C2. For example, entering 175 should return something close to 135. (175 is between 165 and 181 in A, returning something between 129 and 138 in B. I did that one on paper.) Of course, if some number that is actually known in A is entered, the corresponding value in B should be returned.
I guess I don't understand the FORECAST function, because using the exact ranges as in this example it returned 129.1 for 175.

### Excel Facts

How to create a cell-sized chart?
Tiny charts, called Sparklines, were added to Excel 2010. Look for Sparklines on the Insert tab.

#### venkat1926

##### Well-known Member
HIGHLIGHT the values in columns A and B and draw a xy scatter diagram
values in column A will be in x axis and col B will be in y axis
at first locate the chart in the sheet itself.

click the points in the chart. go chart menu in the menu bar.
click ADD TRENDLINE. In the trend line window click logarithmic (second chart in the first row) and choose OPTIONS and check DISPLAY EQUATION ONCHART and click OK.
now a smooth curve will be drawn on the chart and
the equation will be on the chart like this
y=79.667Ln(x)-281.25
here Ln means logarithm to base e(exponential)
in any cell type this formula (for x value 175)

=79.667*LOG(175,2.7182818)-281.25

it comes to 130.213.

You can experiment with various types of charts depending upon how your scatter diagram looks.
+

Replies
4
Views
641
Replies
4
Views
956
Replies
4
Views
576
Replies
2
Views
151
Replies
3
Views
80

1,191,174
Messages
5,985,102
Members
439,940
Latest member

### We've detected that you are using an adblocker.

We have a great community of people providing Excel help here, but the hosting costs are enormous. You can help keep this site running by allowing ads on MrExcel.com.

### Which adblocker are you using?

1)Click on the icon in the browser’s toolbar.
2)Click on the icon in the browser’s toolbar.
2)Click on the "Pause on this site" option.
Go back

1)Click on the icon in the browser’s toolbar.
2)Click on the toggle to disable it for "mrexcel.com".
Go back

### Disable uBlock Origin

Follow these easy steps to disable uBlock Origin

1)Click on the icon in the browser’s toolbar.
2)Click on the "Power" button.
3)Click on the "Refresh" button.
Go back

### Disable uBlock

Follow these easy steps to disable uBlock

1)Click on the icon in the browser’s toolbar.
2)Click on the "Power" button.
3)Click on the "Refresh" button.
Go back