20kg.fitness

Engineer your
training.

The most customizable workout builder ever made, for lifters who'd rather engineer their programs than download them. A spreadsheet-style formula engine projects every cycle forward, automatically.

Cycle 2›Week 3›Day 1 · Lower saved
Back Squat straight · 3×5

computed by a formula

Write the rule once.
The program writes itself.

Any cell can hold a formula that resolves against the same exercise’s most recent earlier appearance. Type =PREV(weight)+2.5 in week one and every cycle that follows projects forward on its own. No copy-paste, no spreadsheet of your own to maintain.

=PREV(weight)+2.5 drives the violet weeks. Change the rule, every week downstream recomputes.

Not locked into one school of thought.

Conjugate today, 5/3/1 next block, undulating on your accessories: mix any methodology in a single program. Nothing is hardcoded, so the tool bends to your method instead of the reverse.

How you periodize

  • 5/3/1
  • Conjugate
  • DUP
  • Block periodization
  • Linear progression
  • Wave loading
  • RPE autoregulation
  • %1RM targets
  • Scheduled deloads

How you structure sets

  • Reverse pyramid
  • AMRAP
  • Cluster sets
  • Rest-pause
  • Drop sets
  • Myo-reps
  • EMOM
  • Supersets
  • Tempo & pauses

See everything.
Optimize everything.

Volume and tonnage by muscle, estimated-1RM trends, a weekly training heat map, fatigue and recovery, PR history: every number your program generates, read back to you.

Weekly heat map effective sets · by muscle
Squat e1RM 12-week trend
178kg +26 over 12 wk
Weekly tonnage total kg moved

deload weeks dip automatically

Nothing is hardcoded.

Total control over sets, reps, loading methods, periodization, and the math that drives progression. Six levels deep, every one of them yours to shape. Auto-saved to your browser. Export the whole thing as JSON whenever you want it.

  1. Program
  2. Cycle
  3. Week
  4. Day
  5. Exercise
  6. Set

The builder, live today.

The real app, open to a showcase program. Formula cells, progression and deload rules, loading schemes and time formats: everything you saw above, working today.

20kg.fitness/app
The 20kg.fitness builder showing a real program: editable set grids for Back Squat and Bench Press with weights, reps, and per-set methods like straight sets and pyramid, alongside tempo and rest fields and per-exercise Progression and Deload controls.
The /app builder, exactly as it ships.

Straight answers.

It’s live today. Why a waitlist?
The builder is real and usable right now: what you see above is the actual product. The waitlist is how you lock in lifetime founding pricing and get in before the public launch.
Does it work on my phone?
Yes. It’s a fast, responsive web app. Build and review your programs on any device, with nothing to install.
Do I own my data?
Always. Everything auto-saves in your browser, and you can export your whole program as JSON whenever you want. No lock-in.

Founding access.

Join the first cohort. Early access before public launch, plus lifetime founding pricing locked in for good.