Math Professor’s ‘Christmas Tree Lights Spacing Calculator’ Creates Perfectly Lit Christmas Trees

Kathy Dean News 1 Comment

MOBILE, Ala. – A University of Mobile mathematics professor has solved one of the frustrations of the Christmas season by developing the Christmas Tree Lights Spacing Calculator that anyone can use.

Dr. Troy Henderson, professor of mathematics, developed the online calculator after he and his wife, Greta, were faced once again with figuring out how to evenly space lights on their tree without running out too soon or having too many left over.

“This year we were too greedy with the lights at the bottom of the tree, and therefore we were in need of too many lights at the top to ‘tweak’ the spacing for complete coverage. We were forced to either pull the lights off and start again or purchase another strand of lights,” Henderson wrote in a blog on The Torch, the digital magazine of University of Mobile.

They bought more lights, but the problem of uniform spacing still troubled him.

“As a mathematician and a problem-solver, I still wanted to know the optimal spacing of the lights so that the distribution is uniform and the precise number of lights are exactly used without tweaking them,” he said.

The online calculator uses the diameter of the Christmas tree at its base, the height of the tree, and the length of the strands of lights on hand. Input the numbers, and the calculator computes the vertical spacing you should have between rotations, the number of rotations you will have, and creates a picture demonstrating the result.

The Christmas Tree Lights Spacing Calculator is just one example of how Henderson challenges students to see mathematical problems in everyday life, and to have fun and a sense of personal accomplishment in discovering solutions. The professor has also worked out a mathematical model for the cooking process of smoking barbecue.

Henderson’s blog with a link to the Christmas Tree Lights Spacing Calculator is at


About University of Mobile:
University of Mobile is a Christ-centered liberal arts and sciences institution with a vision of higher education for a higher purpose, founded to honor God by equipping students for their future professions through rigorous academic preparation and spiritual transformation. Core values are: Christ-Centered, Academically-Focused, Student-Devoted and Distinctively-Driven. The university offers on-campus and online bachelor’s and master’s degree programs in over 40 areas of study. Founded in 1961, University of Mobile is affiliated with the Alabama Baptist State Convention and is located 10 miles north of Mobile, Alabama on a campus of over 880 acres. For more information about University of Mobile, visit the website at or call Enrollment Services at 1.800.WIN.RAMS or 251.442.2222.

About the Author
Kathy Dean

Kathy Dean

Kathy is an award-winning public relations professional and former journalist with a strong background in strategic communications, feature writing/story-telling, copywriting and editing. She serves as assistant vice president for university communications. Kathy joined the University of Mobile marketing/public relations staff in 1993 and has earned awards for writing, public relations and advertising, including twice receiving the grand prize for feature writing from the Baptist Communicators Association. She serves on the board of the John M. Will Scholarship Foundation, awarding scholarships to promising student journalists; and is a member of the Public Relations Council of Alabama, Baptist Communicators Association and Society of Professional Journalists. Kathy lives in Daphne with her husband, Chuck, who earned his M.B.A. from University of Mobile. They have two children and two grandchildren.

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