Meet the Creator
Jonas Lindemann
Software Developer & Dedicated Triathlete Building Tools for Athletes
I combine over a decade of hands-on endurance sports experience with my software development background to create calculators that actually help athletes train smarter.
10+
Years of Training
Hamburg, Germany
Based in
Cycling, Running, Swimming
Sports
Ironman 2027
Current Goal
Why I Built Sport Calculator
As both a software developer and a passionate endurance athlete, I've spent countless hours searching for reliable training tools. What I found was frustrating: calculators that didn't explain their methods, outdated formulas, and tools that clearly weren't built by people who actually train.
I wanted calculators that I could trust - tools built on real science that I could use to plan my own training. When I couldn't find them, I built them myself.
Every calculator on Sport Calculator comes from a real need I've experienced in my own training. The FTP calculator? I was frustrated with inaccurate estimates. The gear ratio calculator? I bought the wrong chain length too many times. The calorie calculators? I wanted to understand exactly how energy expenditure is calculated, not just trust a black box.
My promise: Every tool on this site explains exactly how it works. No hidden formulas, no mystery algorithms - just transparent, science-based calculations that you can understand and trust for your own training.
My Training Journey
Over a decade of endurance sports experience shapes every calculator I build
Started Cycling
Began cycling as a primary form of exercise, quickly developing a passion for both indoor and outdoor riding.
Added Running
Incorporated running into my training routine, starting with shorter distances and gradually building up.
Discovered Zwift
Started indoor training with Zwift, diving deep into power-based training and structured workouts.
First Triathlon Training
Began swimming training and started combining all three disciplines for triathlon preparation.
Launched Sport Calculator
Combined my software development skills with endurance sports knowledge to create Sport Calculator.
Ironman Goal
Working toward completing my first full Ironman distance triathlon.
Sport-Specific Experience
Real hands-on experience in each discipline informs the tools I create
Cycling
Cycling has been the cornerstone of my endurance training journey. From early morning Zwift sessions to challenging climbs in Mallorca, I've accumulated thousands of kilometers on the bike. This hands-on experience directly influences the cycling calculators I've built - from the FTP calculator to the gear ratio tools.
Key Experience:
- Regular indoor training on Zwift with 3-4 sessions per week
- Outdoor cycling in Hamburg and surrounding regions
- Annual cycling trips to Mallorca for training camps
- Deep understanding of power-based training zones and FTP testing
- Experience with bike fitting, gear ratios, and equipment optimization
Running
Running complements my cycling and serves as a crucial component of triathlon training. I've learned the importance of pacing, recovery, and the delicate balance between volume and intensity. This experience shapes tools like the pace calculator and calorie estimators.
Key Experience:
- Regular running training integrated with cycling and swimming
- Experience with various running distances from 5K to marathon
- Treadmill training for controlled pace and incline workouts
- Understanding of pace zones, cadence, and running economy
- Brick workouts combining running with cycling for triathlon prep
Triathlon
My triathlon journey represents the convergence of all my endurance sports experience. Working toward an Ironman finish by 2027 keeps me deeply engaged with training science, nutrition timing, and the mental aspects of ultra-endurance sports.
Key Experience:
- Active pursuit of Ironman distance completion by 2027
- Experience balancing three disciplines in training
- Understanding of transition strategies and race-day nutrition
- Knowledge of swim-bike-run energy management
- Continuous learning about endurance performance optimization
The Journey to Ironman 2027
I'm currently training for my first full Ironman distance triathlon. This ongoing journey keeps me deeply connected to the challenges athletes face and continuously inspires new tools and improvements to Sport Calculator.
Follow along through the blog where I share training insights, lessons learned, and the science behind endurance performance.
Built by an Athlete, for Athletes
Every calculator on this site is the result of real training experience combined with rigorous research. If you have suggestions for new tools or improvements, I'd love to hear from you.