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1RM Calculator

Estimate your one rep max using the Epley formula

Chest10 exercises

Barbell bench press Bench PressIncline Bench PressDecline Bench PressDumbbell Bench PressDumbbell FlyDumbbell PulloverMachine Chest PressPec DeckSmith Machine Bench PressCable Fly

Legs26 exercises

SquatFront SquatRomanian DeadliftHip ThrustSumo DeadliftGood MorningBarbell LungeDumbbell LungeGoblet SquatBulgarian Split SquatDumbbell Romanian DeadliftLeg PressLeg CurlLeg ExtensionCalf Raise MachineHack SquatSmith Machine SquatSmith Machine LungeHip Abduction MachineHip Adduction MachinePendulum SquatBelt SquatGlute Kickback MachineLying Leg CurlStanding Calf Raise MachineKettlebell Swing

Back10 exercises

DeadliftBarbell RowBarbell ShrugDumbbell RowDumbbell ShrugLat PulldownSeated RowBack Extension (Roman Chair)Machine PulloverCable Pullover

Shoulders14 exercises

Overhead PressBarbell Upright RowLandmine PressDumbbell Shoulder PressLateral RaiseRear Delt FlyDumbbell Front RaiseArnold PressMachine Shoulder PressSmith Machine Shoulder PressMachine Reverse FlyFace PullCable Lateral RaiseCable Upright Row

Arms16 exercises

Barbell CurlClose Grip Bench PressSkull CrusherDumbbell CurlDumbbell Tricep ExtensionHammer CurlConcentration CurlIncline Dumbbell CurlDumbbell KickbackMachine Bicep CurlMachine Tricep ExtensionMachine Preacher CurlSeated Dip MachineTricep PushdownCable CurlCable Kickback

Full Body3 exercises

Power CleanTurkish Get-upKettlebell Clean & Press

Core4 exercises

Abdominal Crunch MachineTorso Rotation MachineCable WoodchopCable Crunch

What is 1RM?

1RM (one rep max) is the maximum weight you can lift for a single repetition of a given exercise. It is a standard measure of muscular strength used by coaches, athletes, and researchers worldwide.

The Epley Formula

This calculator uses the Epley formula: 1RM = Weight × (1 + Reps ÷ 30). It provides a reliable estimate when lifting in the 2-12 rep range.

How to Use Your 1RM

Knowing your 1RM helps you structure your training. Use 60-70% for endurance (12-20 reps), 70-85% for hypertrophy (6-12 reps), and 85-95% for strength (1-5 reps).

The Ultimate Workout Tracker

Log weight, reps & sets. Auto-estimate 1RM and calories. Completely free, no ads.

GymGrid automatically estimates your 1RM from your training data

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Quick to log between sets. Seeing my last session instantly means no more guessing what weight to use.

— 4x/week lifter

Free with all these features? Switched from a subscription app and haven't looked back.

— 3 years lifting

Love the simple UI. No clutter, just tracking. Exactly what I needed.

— Gym beginner

Update History

v2.1.12026-06-05
  • New "Display" setting under Timer lets you choose between the full-screen rest timer (existing behavior) and a compact pill at the bottom of the entry screen.
  • Fixed: 3-digit interval values (e.g. 120s, 180s) no longer wrap to a second line in the rest timer.
  • Fixed: Grid cells with multi-digit weight × reps now stay on one line via auto-shrink.
v2.1.02026-06-04
  • New: Optional rest timer. Turn it on in Settings to see a full-screen countdown or count-up after each set. Customize the interval per exercise, with video-player-style controls (-10s / pause / +10s) and Skip to end early.
v2.0.02026-06-03
  • GymGrid is now completely free — we want every lifter to be able to use it.
  • Fixed an issue where the Log screen showed kg even when the weight unit was set to lb.
v1.5.12026-05-28
  • The widget can now show your total calories burned (when calorie display is on)
  • Added support for the small widget size
  • More compact set rows on the workout logging screen
  • Tuned the activity heatmap colors so differences in training volume stand out more
v1.5.02026-05-27
  • Add a note to any set — tap the note icon to jot down how it felt or a form cue.
  • New Display Settings (gear icon) on the Records and Analysis screens to show/hide and reorder your exercises.
  • New Home Screen widget that shows your training consistency at a glance.
v1.4.32026-05-25
  • Exercise search now matches hiragana input.
  • Muscle map on the logging screen so you can see target muscles before training.
  • Fixed muscle map rendering (lats, triceps, hamstrings, and more now display correctly).
  • Clearer guidance for the schedule day picker.
  • Fixed an issue where the onboarding guide could reappear after restarting.
v1.4.22026-05-25
  • Minor improvements and bug fixes.
v1.4.12026-05-24
  • Fixed the achievement date shown on Big 3 award cards so it reflects the date you actually logged the weight.
  • Minor improvements and stability fixes.
v1.4.02026-05-22
  • Analysis charts now scroll horizontally to look back over time, with week/month/year zoom for volume
  • Celebrate and share new Big 3 personal records (bench/squat/deadlift), with per-exercise milestone awards
  • New "Save Image" button to save workout and award images straight to Photos
  • Fixed onboarding reappearing when relaunching the app
v1.3.12026-05-21
  • Fix share image white corners on X/Twitter
  • "Save Image" option now available in share sheet
  • Fix drag-to-reorder indicator alignment for tall rows
  • Added "Update App" link in Settings
v1.3.02026-05-20
  • Share your workouts as images on social media
  • Volume chart view in the Analysis tab
  • Tap recent session to quick-load all sets
  • UI improvements and bug fixes
v1.2.32026-05-19
  • Swipe left/right to switch weeks
  • Drag exercise names to reorder
  • View last 5 sessions on recording screen (horizontal scroll)
  • Larger add-set button for easier tapping
v1.2.22026-05-18
  • Larger add-set button for easier tapping
  • View previous session's sets on the recording screen
v1.2.12026-05-17
  • Schedule filter now auto-navigates to the correct week
  • Set input screen auto-scrolls to the latest set
  • 1RM field now shown when adding weighted exercises
  • Improved 1RM guidance with auto-estimation info
  • Bug fixes and performance improvements
v1.2.02026-05-16
  • Exercise icons now shown in set input screen for official exercises
  • Added suggestion pills for cardio exercises (speed, incline, time)
  • Improved cardio chart labels (km/h, auto sec/min display)
  • Added schedule filter (All / Today / Tomorrow) to Grid screen
  • Tap exercise name in Analysis to view max trends over time
  • Bug fixes and performance improvements
v1.1.12026-05-15
  • Fixed calorie calculation accuracy for treadmill walking
  • Fixed filter display issue on the history screen
v1.1.02026-05-15
  • New gold brand design
  • Cardio machine support (treadmill, bike, elliptical) — track speed, duration, and incline
  • Edit records by tapping on them
  • Pocket Lock: lock the screen while training
  • Improved calorie calculation accuracy
  • Advanced exercise settings (equipment, muscles, MET)
  • Onboarding guide for new users
  • Seconds/minutes toggle for timed exercises