Methodology
How our calculators and guides are made
This page explains where the numbers on Leg Day Supply come from, what their limits are, and how the guides are researched, checked and kept up to date. Everything here is written and maintained by Mario Puerto.
Calculators: formulas and limits
| Calculator | Method | Main limits |
|---|---|---|
| One-rep max | Average of the Epley, Brzycki and Lombardi formulas | Less accurate above 10 reps or on sets far from failure |
| Strength standards | Body-weight ratios for five levels, using an e1RM from Epley and Brzycki | Rules of thumb for raw adult lifters, not official standards; no age adjustment |
| RPE | RPE percentage chart popularized by RPE-based powerlifting coaching | Depends on how accurately you rate your sets |
| DOTS & Wilks | Published DOTS and original Wilks coefficients | Federations differ in which score they use |
| TDEE & macros | Mifflin-St Jeor equation × activity multiplier; protein at 2 g/kg, fat at 25% of calories | An estimate; real needs vary by a few hundred calories |
| Protein | g/kg ranges drawn from meta-analyses and position stands on protein and resistance training | Not for people with kidney disease or other medical conditions |
| Body fat | US Navy circumference method; categories from the American Council on Exercise | Can be off by several percentage points; best for tracking trends |
| Plates and warm-up | Arithmetic using standard bar and plate weights | Assumes your plates weigh what's printed on them |
Every calculator runs entirely in your browser. Nothing you type is sent to us or stored.
How guides are researched
- Sources first. Training and nutrition guides are based on systematic reviews, meta-analyses, position stands from organizations such as the International Society of Sports Nutrition, and official competition rules. Each guide lists its main sources at the end.
- Plain numbers. Where research gives a range, we give the range and explain who should be at which end of it, instead of a single magic number.
- Real questions. Topics are chosen from what lifters actually search for and ask us, so each guide answers a specific question.
How pages are checked
- Every figure in a table is calculated with the same formulas used by our calculators, not typed by hand.
- Health-related claims are checked against the sources listed on the page before publishing.
- Each page shows the date it was last updated. Guides are reviewed when new research or rules change the answer.
How we use AI tools
We use AI tools to help with research, drafting and code, the same way we use spreadsheets and calculators. AI never has the final word: every page is reviewed by a person, every number is checked with our own formulas, and claims are checked against the published sources listed on the page.
Independence and advertising
We don't accept payment for coverage or recommendations. The site is funded by display advertising and by our own shop. Advertisers have no say over what we publish.
Corrections
If you find an error, email legsdaysupply@gmail.com with the page and what's wrong. Confirmed mistakes are fixed and the page's update date is changed.
Not medical advice
Our calculators and guides are general information for healthy adults. They don't replace a doctor, registered dietitian or qualified coach. See our terms of use for details.