The J2J Training Lab
Free training calculators
We wanted to share these free tools with you to support you on your journey to jacked. Every one of them shows its working: the formula, the research behind it, and what the number actually means for your next session.
All 5 are free and ungated. No account, no email wall, no trial. Use one, use all of them, close the tab.
The tools
Each one answers a single question. Start with whichever question you are currently stuck on.
Free toolStrength
Your 1RM + every rep range
1RM Calculator
Enter a set you have actually done and get your estimated one-rep max, plus a full loading breakdown for every rep range from singles to sets of twelve. This is the number every percentage-based program is built on, so it is the first one worth knowing.
Free toolBar Loading
Exact plates, per side
Plate Calculator
Stop doing arithmetic between sets. Enter a target weight and get the exact plates per side, in kg or lbs, for your barbell and your gym’s plate set. Handles odd bar weights and incomplete plate sets, which is most real gyms.
Free toolNutrition
Calories + 4 macro splits
Macro Calculator
Enter your stats and pick a goal (cut, maintain, or bulk) and get daily calorie and macro targets built around your bodyweight, activity level, and training frequency. Four split options, so you can pick the one you will actually stick to.
Free toolFrame + FFMI
Body-part potential map
Muscular Potential Calculator
Calculate your FFMI, your maximum drug-free bodyweight, and how each individual muscle group measures against its natural ceiling. Based on published sports science research rather than gym folklore, which usually means the ceiling is further away than people fear.
Free toolBiomechanics
Built around your leverages
Squat & Deadlift Form Visualizer
Long femurs are not bad form. Enter your femur, torso, and shin measurements and watch how they reshape your ideal squat and deadlift: stance width, heel elevation, bar path, and whether sumo or conventional suits your build. The figure moves with your numbers.
What a calculator can’t do
Worth being straight about, because the gap between these two columns is exactly the gap a real program fills.
What these give you
- Give you a defensible starting number instead of a guess.
- Show the working, so you learn the logic rather than just the output.
- Tell you when your build, not your technique, is the reason a lift feels wrong.
- Sanity-check a program someone else wrote for you.
What they don’t
- Replace progressive overload. A number is a starting point, not a training block.
- Account for sleep, stress, or the week you had.
- Decide your exercise selection, set volume, or how the load moves week to week.
- Tell you what to change when the numbers stop moving for three weeks straight.
The next step
Numbers are the easy part
A calculator tells you where you stand today. It won’t tell you what to do on Monday, or how the load moves over the next twelve weeks. That takes a program built around your body, your equipment, and the days you can actually train.
Build my program7 questions · No subscription