531 Strength is a focused tracker for lifters running Jim Wendler's 5/3/1 program. No coaching, no social, no ads. Just a clean digital notebook for your training maxes, your working sets, your AMRAPs, and the PRs you chase across each 4-week cycle.

Built for the program. 5/3/1 percentages, BBB volume work, and AMRAP set logging are all here. Plate math is done for you: by bar, by plate set, in pounds or kilograms, shown per side. Training max progression follows the 5 lb / 2.5 kg upper-body, 10 lb / 5 kg lower-body rules. No manual math after every cycle.

In the gym. A countdown rest timer between sets, with a buzz when time's almost up. Your screen stays awake. Log your AMRAP top set and the app flags a PR the moment you save it.

History that feels earned. Every session you've filed, your personal records, your longest training streak, and a quiet record of your last cycle's training days. No "achievements" plastic. Just the numbers that matter.

Made for a bright gym. Monochrome, calm, readable. The screen feels like the next page of your training log instead of a flashing dashboard.

Yours alone. Your sessions, your PRs, your training maxes stay on your phone. No account. No sign-in. No social network. No ad targeting. No tracking, in the gym or out of it.