Disclaimer

Last updated: September 2026. Please read this page carefully before using our calculators.

Educational information only

All content on LiftMath — calculators, articles, tables, and examples — is published for general educational purposes. It is not medical advice and is not a substitute for a qualified professional. We are not physician or registered dietitians, and no client or advisory relationship is created by your use of this Site.

Our calculators implement standard strength formulas — Epley, Brzycki, standard percentage charts — validated across trained populations. Rep-max estimates carry 3–8% error bars and individual variation that a coach watching your reps in reserve can price better than any formula.

Progressive overload is safe when progression is gradual and form holds. Loads recommended here assume sound technique; pain, form breakdown, or ego lifting are the injuries the formulas cannot see.

Accuracy of calculations

We implement well-known, publicly documented formulas (see the methodology section on each calculator page and NIH and CDC public guidance as applicable). Even correctly implemented formulas produce estimates that depend on your inputs and assumptions. Real-world outcomes vary. Do not rely on a single web tool for a consequential decision.

Advertising disclosure

LiftMath is funded by display advertising served through Google AdSense. Advertisers have no influence over our content, formulas, or editorial choices, and placement of an ad is not an endorsement.

Errors and corrections

If you spot an error, please email contact@nftycalcs.com with the inputs you used. Verified corrections are published promptly.