GOAT LabLiftLab: 14 offline 1RM, plate loading & strength calculators
LiftLab is a free, fully client-side set of 14 barbell calculators — 1RM estimators, %1RM and RPE/RIR charts, plate loading math, Wilks/DOTS/IPF GL scores, warm-up ramps and home gym planning — that run instantly in your browser. Every result is a training-math estimate, not medical or coaching advice.
- Free
- No sign-up
- Works offline
What is LiftLab?
LiftLab bundles 11 everyday strength-training calculators across four areas: 1RM & strength (1RM estimation averaged from Epley, Brzycki, Lombardi and O'Conner, a %1RM training chart, an RPE/RIR-to-%1RM converter, and Wilks/DOTS/IPF GL powerlifting scores), barbell & plates (plate loading math, a plate-inventory combinator for plates you already own, and a warm-up set generator), programming & volume (tonnage and training-volume tracking, a linear-progression planner, and an IPF/IWF weight-class planner), and home gym & gear (a home-gym space and ceiling checker) — plus 3 reference tables: bodyweight-ratio strength standards, a plate color & kg⇄lb reference, and a resistance-band tension chart. Everything is computed locally with no server, no account, and no upload.
How does it work?
Each calculator runs as client-side JavaScript using published formulas — for example 1RM = weight × (1 + reps/30) (Epley), averaged with three other estimators, or per-side plate loading solved with a largest-plate-first greedy algorithm. The %1RM, RPE, and warm-up tools all chain off your entered or estimated 1RM to build full tables and set-by-set plans automatically, so the numbers stay consistent across every calculator. No input ever leaves your browser.
When should I use it?
Use LiftLab to estimate a 1RM from a hard set, plan training percentages or RPE targets, work out plates per side for a target bar weight, check a Wilks/DOTS/IPF GL score, or size a home gym around a rack and platform. Results are statistical estimates from published formulas, not medical or coaching advice — always confirm maximal lifts with spotters or safety pins. Calorie, BMR, and nutrition math live in the Everyday Lifestyle toolbox on this site, not here.
At a glance
| Calculators | 14 (11 calculators + 3 reference tables) |
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| Areas | 1RM & strength, barbell & plates, programming & volume, home gym & gear |
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| 1RM formulas averaged | Epley, Brzycki, Lombardi, O'Conner (e.g. 100 kg × 5 reps ≈ 116.7 kg) |
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| Powerlifting scores | Wilks, DOTS (2019), IPF GL (2020) — classic or equipped |
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| RPE chart | Tuchscherer/RTS convention, RPE 6.5–10 × reps 1–10 |
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| Processing | 100% client-side — no server, no upload |
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| Account | None — free, no sign-up, works offline |
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| Languages | en, ja, es, zh, de |
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Frequently asked questions
What is my 1RM if I bench press 100 kg for 5 reps?
Using the Epley formula, 1RM ≈ 100 × (1 + 5/30) ≈ 116.7 kg. LiftLab averages Epley with three other published estimators (Brzycki, Lombardi, O'Conner) and shows each formula's result alongside the average, since single-formula estimates can differ by a few kilograms.
How many plates go on each side for 140 kg on a 20 kg bar?
Per side = (140 − 20) / 2 = 60 kg. With standard kg plates (25/20/15/10/5/2.5/1.25), that's two 25 kg plates and one 10 kg plate per side — six plates plus the bar in total. LiftLab's plate loading calculator shows the full per-side breakdown and a bar diagram for any target weight, bar, and plate set.
What percentage of 1RM is RPE 8 for 5 reps?
RPE 8 at 5 reps has an effective-reps value of 5 + (10 − 8) = 7, which maps to about 81.1% of 1RM on LiftLab's RPE/RIR chart (Tuchscherer/RTS convention). At a 150 kg 1RM that's roughly 122.5 kg once rounded to the nearest 2.5 kg plate.
Is my data uploaded?
No. Every calculation runs entirely in your browser. Your inputs never leave your device.
Do I need an account?
No. LiftLab is free, needs no sign-up or install, works offline once loaded, and is available in English, Japanese, Spanish, Chinese and German.
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