About StrengthMath

Strength calculators that explain the number.

Who runs this

StrengthMath is written and maintained by Jimmy L Wu. Data-driven training analyst with practical gym-floor literacy. StrengthMath covers 1RM math, training percentages, plate loading, and population strength benchmarks — sourced from ACSM, NSCA, AAP, and peer-reviewed prediction-formula research.

The framing is deliberate: practitioner-analyst, not certified coach.I lift, read the literature, and run the numbers — I don't hold an NSCA CSCS, an ACSM EP-C, or a USAW credential. For programming specifically tailored to your physiology, training history, or competition goals, work with someone who does. StrengthMath's job is to make the underlying math legible and sourced — so when a coach tells you “run 80% × 5,” you can audit what that number rests on.

What this site is for

The strength corner of the internet has two failure modes. The first is gym-bro forum lore — confidently wrong, source-free, contradicted by the next thread down. The second is certified-trainer marketing copy — accurate enough to not get sued, but vague where the actual decisions live. StrengthMath sits in the third position: every formula, band, and threshold is reproduced from a primary reference (NSCA, ACSM 2026 Position Stand, AAP guidance for minors, peer-reviewed validation studies), and where the published literature ends and StrengthMath methodology fills the gap, the page says so explicitly.

Concretely:

• 1RM estimation from submax reps with all four published formulas and reliability bands per LeSuer 1997 — not a single formula presented as gospel.
• Training-percentage tables with NSCA traditional bands and the ACSM 2026 update surfaced side by side — power widened to 30–70%, hypertrophy deprioritizing %1RM. Pick the framing that matches your program; both are sourced.
• Dumbbell-vs-barbell math that admits there's no consensus conversion factor and surfaces a wide honest range with five specific caveats — not a false-precise number that pretends the implements are interchangeable.
• Teen-mode strength standards that use soft framing only (“still building” / “above typical beginner”) and quote the AAP directly on power-lifting / max-attempt safety for minors — never assigning elite or advanced labels to a 13-year-old.

What you won't find here

No invented gym anecdotes. No “in my 20 years coaching pro athletes” padding from someone who hasn't. No AI-generated stock photos of barbells presented as real photographs. No comparison tables sourced from competitor calculators or scraped off forums. When a number on this site has uncertainty, the calculator widens its band rather than hiding the spread. When the literature is sparse — minor strength competition data, dumbbell-to-barbell conversion factors — the site says so and labels its own framing as methodology, not as published truth.

How the math is sourced

See /methodology for the full per-engine sourcing model and worked examples, and /editorial-policy for review cadence, AI policy, and corrections.