Excel world champion explains which function saves the most time

Excel is one of the most used office programs. However, when it comes to utilizing the full range of functions, many professionals reach their limits. Diarmuid Early, who took first place at the Excel World Championship in 2025, revealed his most important tips in an interview with Business Insider.

Every beginning is difficult – even with Excel

Diarmuid Early discovered his enthusiasm for Excel while studying. He later used his knowledge at the Boston Consulting Group (BCG). He then worked for ten years at Deutsche Bank, where data analysis and financial reporting were among his key tasks. Today, Early is self-employed and runs his own consulting company, with which he supports companies in the professional use of Excel. The program has accompanied him throughout his entire professional career.

“My number one tip for office workers is to believe there is a better way,” he said. “Anytime you do something manually and repetitively, there’s very likely a better way in Excel.” He particularly recommends the “Sumifs” function, also known in German as “Summewenn”. It allows values ​​in a range to be summed when several defined criteria are met. Getting started takes some time at first, but learning success accelerates significantly with each additional application, says Early.

Excel can save you hours of work

“The worst thing I find is when I see a formula that consists of 50 different numbers in the form A1 + B3 + C5 + D10. Someone has obviously entered them all by hand or by clicking, clicking, clicking,” Early said in the interview. “It takes a lot of time to do this, and the likelihood of making a wrong click and making a mistake that you’ll never find again is very high.” Automated functions, on the other hand, are significantly less prone to errors.

The expert also emphasizes how important it is to have time to classify the content of the results. It’s great when you can quickly click through a table and get straight to the result, says Early. This leaves enough room to critically question the numbers. “This is something that young bankers and consultants do least of all. They see it as their job to apply the model and provide the answer. The next person in the hierarchy then asks: What does this mean? What is the insight? Does that make sense?” Anyone who asks themselves these questions and communicates the results accordingly will gain credibility. “Plus, you’re much more likely to catch your own stupid mistakes before someone else does.”

AI could become an important tool

“Basically, at every level of Excel proficiency, there are things you do wrong and don’t realize until you get to the next level. There are problems everywhere.” AI tools could therefore be of valuable support in the future, especially for beginners: “When the time comes, I think that AI will be very helpful in getting people from bad to not bad or maybe even from bad to good. For people like me, who are already quite experienced, it probably won’t be of much help.”

Excel is installed on almost every company computer – yet its potential often remains unused. Early advocates changing that. “I know 50,000 hacks,” says the world champion. “During my time at BCG, I conducted a lot of Excel training.” He has repeatedly seen that the participants reacted with enthusiasm and shock at the same time after learning a new function. Some told him that if they had known the relevant Excel trick earlier, they wouldn’t have had to work until two in the morning the night before.

This article was originally published in January 2026, but is still of interest to many of our readers. That’s why we’ve updated it and made it available again here.