You know how it goes. You’re sitting around on a Tuesday night, trying to catch up on some highlight reels, and a totally random thought pops into your head. For me, it was something my kid said last week about some school project. He brought up Kylian Mbappé, obviously, and how he scored in the 2018 World Cup final. I just nodded, thinking, “Yeah, kid, he was young.”
But then, later that night, I started chewing on it. How young was he, really? Not just “a teenager.” I needed the exact, down-to-the-day number. My brain works like that—if you give me a piece of easy trivia, I have to completely dismantle it and find the hard-core, unnecessary details. It’s a sickness, I tell ya, but it’s how I document my stuff. I needed to run a proper field report, so I grabbed my notepad and started the whole thing from scratch.
The Prep Work: Digging Up the Dirt
The first thing I had to establish were the two critical numbers. You can’t calculate age without a start date and an end date. Sounds simple, but you gotta be careful because sometimes what you assume is the right date is actually a day or two off, and that messes up the whole thing, especially when you’re dealing with precise ages.
I didn’t bother with some fancy sports almanac. I just went straight to the source, the quick Google punch. I started with the easy one.
Step 1: Finding Mbappé’s Birth Date.
- I hammered the keys: “Kylian Mbappé date of birth.”
- It popped right up: December 20, 1998.
Easy enough. Now for the second half of the equation, the day that actually mattered.
Step 2: Finding the World Cup Final Date.
- The query: “2018 World Cup final date.”
- Answer confirmed: July 15, 2018.
So, I had my two bookends: 1998-12-20 and 2018-07-15. Now came the fun part: the actual calculation. I could have just typed “age calculator” and plugged the numbers in, but where’s the fun in that? I had to do the math myself first, just to get my hands dirty, you know?
The Practice: Running the Numbers Manually
The core challenge is that a year is not 365 days, and months vary, so you have to work backward from the final date and subtract the birthday.
Starting with the Years:
2018 minus 1998 gives you 20 years. That’s the big chunk. But we’re not done, because the World Cup Final (July 15) happened before his 20th birthday (December 20).
So, I knew he hadn’t turned 20 yet. That meant I had to slide the year count back one notch.
- Years: 19.
Moving to the Months:
Now I needed to count the months between his last birthday in 2017 (December 20) and the final date in 2018 (July 15).
- December 20 to January 20 = 1 month
- January 20 to February 20 = 2 months
- …all the way up to June 20.
That gives me 6 full months (January through June). Now I’m at June 20, 2018.
- Months: 6.
Finally, the Days:
I’m sitting at June 20, 2018, and I need to get to July 15, 2018. June has 30 days. So, from the 20th to the 30th is 10 days left in June. And then another 15 days in July.
10 days + 15 days = 25 days.
- Days: 25.
The final number, the one I wrote in big, fat marker on my notepad, was: 19 years, 6 months, and 25 days.
The Interesting Details: Why This Matters
Once I had the final, exact, documented age, that’s when you get to the real payoff. This isn’t just trivia; this age has context. Remember that argument my kid sparked? Well, once I locked in that number, I immediately had to cross-check it with the other young legend, Pelé.
This is where the ‘don’t miss the interesting details’ part comes in.
Mbappé was the second teenager ever to score in a World Cup final, obviously, Pelé being the first back in 1958. Now I could finally compare them with real precision.
I did a quick lookup on Pelé’s details for his 1958 final goal against Sweden.
- Pelé’s DOB: October 23, 1940.
- 1958 Final: June 29, 1958.
- Pelé’s Age: 17 years, 8 months, 6 days.
See? That comparison is useless unless you have the exact, detailed age for both. Now I can officially document that while Mbappé was one of only two, he was still over a year and a half older than Pelé was when he scored his first final goal. It closes the loop perfectly.
I keep this record in my notes now. It’s not about the soccer, it’s about the ability to take a sloppy question (“How old was he?”) and turn it into a completely clean, documented, cross-referenced, and verified fact. And that, my friends, is the process. It’s the only way to do it right. Take the time, run the numbers yourself, and confirm the details.
It was a good Tuesday night. I fixed my kid’s school project before he even knew it was broken.
