Converting HSL to RGB

Written by Allen Wyatt (last updated November 16, 2023)
This tip applies to Excel 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365


4

Bassel needs a formula that can convert HSL color values (hue, saturation, and lightness values) to RGB color values (red, blue, and green values). He wonders if anyone can point him to either a worksheet formula that will do this or a way to do it in a macro.

Converting from HSL to RGB values is not a particularly trivial undertaking. For those interested in the math behind it, you can check out the Wikipedia article on the topic.

If you need to do the conversion infrequently, the easiest way is to follow these steps:

  1. Display the Home tab of the ribbon.
  2. Click the down-arrow at the right side of the Fill Color tool, in the Font group. Excel displays a small palette of colors and some other options.
  3. Choose More Colors. Excel displays the Colors dialog box.
  4. Make sure the Custom tab is displayed.
  5. Using the Color Model drop-down list, choose HSL. (See Figure 1.)
  6. Figure 1. The Custom tab of the Colors dialog box.

  7. At the bottom of the dialog box you can see the individual values for Hue, Sat, and Lum. Change these values to whatever you want.
  8. Using the Color Model drop-down list, chose RGB. The values shown at the bottom of the dialog box are the HSL values (entered in step 6) converted to RGB.
  9. Click Cancel when done.

This approach assumes that each of your HSL values can be express in the range of 0 to 255. If, however, your HSL values are either an angle (for hue) or a percentage (for saturation and luminance), then you'll need to convert them manually before entering them in step 6. You can convert an angle value by multiplying the angle by 255 and then dividing by 360. Percentages can be converted by multiplying them by 2.55.

If you have a need to get the values more often, then creating your own user-defined function to do the conversion will help. The following example accepts three parameters (Hue, Saturation, and Luminance) and returns a string containing the decimal RGB values separated by commas.

Function HSLtoRGB(Hue As Integer, Saturation As Integer, _
  Luminance As Integer) As String
    Dim r As Integer
    Dim g As Integer
    Dim b As Integer
    Dim C As Double
    Dim X As Double
    Dim m As Double
    Dim rfrac As Double
    Dim gfrac As Double
    Dim bfrac As Double
    Dim hangle As Double
    Dim hfrac As Double
    Dim sfrac As Double
    Dim lfrac As Double

    If (Saturation = 0) Then
        r = 255
        g = 255
        b = 255
    Else
        lfrac = Luminance / 255
        hangle = Hue / 255 * 360
        sfrac = Saturation / 255
        C = (1 - Abs(2 * lfrac - 1)) * sfrac
        hfrac = hangle / 60
        hfrac = hfrac - Int(hfrac / 2) * 2 'fmod calc
        X = (1 - Abs(hfrac - 1)) * C
        m = lfrac - C / 2
        Select Case hangle
            Case Is < 60
                rfrac = C
                gfrac = X
                bfrac = 0
            Case Is < 120
                rfrac = X
                gfrac = C
                bfrac = 0
            Case Is < 180
                rfrac = 0
                gfrac = C
                bfrac = X
            Case Is < 240
                rfrac = 0
                gfrac = X
                bfrac = C
            Case Is < 300
                rfrac = X
                gfrac = 0
                bfrac = C
            Case Else
                rfrac = C
                gfrac = 0
                bfrac = X
        End Select
        r = Round((rfrac + m) * 255)
        g = Round((gfrac + m) * 255)
        b = Round((bfrac + m) * 255)
    End If
    HSLtoRGB = Str(r) & "," & Str(g) & "," & Str(b)
End Function

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (13535) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

MORE FROM ALLEN

Viewing Formulas in Table Cells

Word allows you to insert simple formulas, using fields, in table cells. If you want to see these formulas in their ...

Discover More

Stable Layout on Different Printers

Want your document to print out the same on printers other than your own? This may be an elusive quest, as explained in ...

Discover More

Making Use of Extra Labels

Got extra labels left over after printing a mail merge? Here's what you can do to put those labels to good use.

Discover More

Program Successfully in Excel! John Walkenbach's name is synonymous with excellence in deciphering complex technical topics. With this comprehensive guide, "Mr. Spreadsheet" shows how to maximize your Excel experience using professional spreadsheet application development tips from his own personal bookshelf. Check out Excel 2013 Power Programming with VBA today!

More ExcelTips (ribbon)

Macro Runs Slowly, but Steps Quickly

When you have a macro that processes a huge amount of data, it can seem like it takes forever to finish up. These ...

Discover More

Running a Macro when a Worksheet is Deactivated

When you change from one worksheet to another, you may want to have Excel automatically run a macro for the worksheet you ...

Discover More

Getting Rid of Alphabetic Characters

When you need to get rid of characters in the middle of a cell value, the best way to do it is through the use of macros. ...

Discover More
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

View most recent newsletter.

Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] (all 7 characters, in the sequence shown) in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is 5 + 0?

2023-04-14 14:29:14

Bruce Volkert

Allen,

This was really helpful.

I struggled quite a bit to make my conversions based on documentation all over the internet that used the Mod function. Unfortunately, as you well know, the MOD function only returns integer or long values. This is problematic for the conversions because many of them are working with Saturation, Luminance, and Value in the 0-1 range. Using the Mod function instead of the approach you provide kills the conversion because the values always come back as 0 or 1 when the Saturation, Luminance, and Value are in the 0-1 range. It does not help much to work in the 0-100 range because the RGB system is working in the 0-255 range and you obviously lose fidelity if you only work with 0-100.

I understand that you don't need to know this; but, I sure did. Maybe this comment helps others.

Thanks for all you do.


2020-02-07 04:14:47

ashleedawg

(to clarify my previous comment:)

You say, "You can convert an angle value by multiplying the angle by 255 and then dividing by 360."
I think the hue (angle°) be adjusted as:
hue/360*256
while your formula for "s" and "L" is correct as:
percentage/100*255

The reason for the difference is that with hue, 0° and 360° are the same, but with the other two values (when expressed as percentages) 0% and 100% are quite different. In reality, the difference is so small it's probably not visually noticeable one way or the other.


2020-02-07 04:03:17

ashleedawg

You say, "You can convert an angle value by multiplying the angle by 255 and then dividing by 360. "

Shouldn't it be: angle * 256 / 360 ?


2018-06-03 06:56:02

Mike

Since this article is really about excel, and using macros, and not about photography, it is possibly a little pedantic to take issue with the title, but my understanding is that 'lightness' and 'luminance' are not the same thing. A couple of links to explain the difference better than I can: https://fxhome.com/forum/discussion/3357/luminance-vs-lightness and https://forums.creativecow.net/docs/forums/post.php?forumid=2&postid=962220&univpostid=962220&pview=t


This Site

Got a version of Excel that uses the ribbon interface (Excel 2007 or later)? This site is for you! If you use an earlier version of Excel, visit our ExcelTips site focusing on the menu interface.

Newest Tips
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.