Log the set. See the next one.

ArchiFit (아키핏) is a free workout log app for people who train alone, on iPhone, with Android coming soon. After each set it suggests the next set's weight and reps from your own sets and your plan's rep range. It also runs a rest timer, marks personal records and builds a weekly report. No account. Records stay on your phone.

Example log: bench press, plan of 6 to 8 reps, 5 lb steps
Set 1	145lb×8
Set 2	145lb×9
Next	150lb×6 one step heavier: set 2 passed the top of 6–8

The app's rule, running here. Bench press, 5 lb steps.

Get ArchiFit on the App StoreComing soon on Google Play

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What happens after each set

Next setOne line above the weight and reps fields: the next set, worked out on your phone from the set you just logged and your plan's rep range. The app labels the line "ArchiFit AI suggestion". It comes from the fixed rules further down this page, and nothing is sent to a server. The fields stay yours to fill.
Rest timerStarts when you log the set. It runs 90 seconds until you change it with −15 s and +15 s, then keeps your length. Short beeps at 3, 2 and 1 seconds left and a long one at the end. On silent it only vibrates, and the end also shows on the lock screen.
First set of the dayWorked out from your last workouts of that exercise and the plan's direction: build muscle, keep your current body or lose body fat.
New recordBeat your heaviest weight for an exercise and a new record screen comes up.

How the next set is worked out, rule by rule.

ArchiFit set screen: set 1 at 145 lb for 8 reps, set 2 at 145 lb for 9 reps, and the ArchiFit AI suggestion reading Next set: 150 lb × 6 reps, heavier than the last set

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Personal records from your own history

A personal record (PR) in ArchiFit is a day whose heaviest set beats every earlier day of that exercise. For body-weight moves it is the most reps in a set. The first day of an exercise sets no record, and matching your best is not a new one.

Records show set counts and total weight by week, 4 weeks or 3 months. Any workout day can be shared as an image card with the day's total weight, a new record or a body change.

ArchiFit share card for a new chest record: 150 lb for 8 reps, up 5 lb on the previous best of 145 lb

8weeks

A weekly report, and an optional 8-week analysis

The weekly report is a few cards to swipe: days trained, sets, total weight, your week streak, the week's best lifts and each body part against its target and last week.

The last card is the AI analysis, and it only runs if you agree. Your phone looks through 8 weeks of sets for lifts stuck at one weight, reps that rose at the same weight and differences by exercise order or days between sessions. Then an AI model writes short paragraphs about what it found, using only numbers from your log. Say no and nothing is sent; the report works the same.

What the analysis checks

ArchiFit weekly report: 3 days trained last week against a plan of 4 days a week, 40 sets, 31,939 lb total volume and a 4-week streak

21%

A plan from an InBody sheet, or without one

Take a photo of an InBody result sheet, pick a photo or PDF, or share it from the InBody app. The phone reads the numbers itself (Apple's text recognition on iPhone, Google ML Kit on Android), shows them for a check, and deletes the photo.

Body fat percentage and skeletal muscle mass set a recommended direction: build muscle, keep your current body or lose body fat. Days per week set the recommended split, and 6–8 reps is the recommended range for every direction, with 12–15 there to pick. Every choice can be changed, and a plan can be chosen with no sheet at all.

How to read an InBody result for bulk, maintain or cut

ArchiFit direction screen: Build muscle recommended because body fat 21% is below the obesity line of 25% and skeletal muscle 70.1 lb is within the standard

0accounts

No account. Your log stays on your phone.

ArchiFit has no sign-in and asks for no name, email or phone number. Workout records, InBody numbers, photos and videos are kept in the app on your phone. Only after you agree to the AI analysis does the app send the last 8 weeks of workout numbers, and the server writes its answer without storing them. Settings can delete every record at once. Privacy details

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How ArchiFit picks the next weight

Every suggestion comes from your own log, with fixed rules that run on the phone. With a plan of 6–8 reps and a 2.5 kg step, which is 5 lb on an lb setting:

The set you just did	Next set
145 lb × 9 (past the top of 6–8)	150 lb × 6. One step heavier, about 5%, inside the 2–10% range the ACSM recommends, back to the bottom of the range
145 lb × 7 (inside the range)	145 lb × 7. Same weight, reps kept in range
145 lb × 5 (under the range)	145 lb × 6. Same weight; within a workout the weight is not lowered for tired reps
Three workouts stuck at 145 lb (build muscle)	Next three workouts: 130 lb × 10, then 140 lb × 8, then 145 lb × 6

In kg the same sets read 65 kg × 9, giving 67.5 kg × 6, and a stall at 65 kg goes 57.5 kg, 62.5 kg, then 65 kg. Read the full method, including the first set of the day and the 8-week analysis.

Questions about ArchiFit

Is ArchiFit free?

Yes. ArchiFit is free to download and has no in-app purchases today. The optional 8-week AI analysis is free too.

Do I need an account?

No. There is no account and no sign-in. The app does not ask for your name, email address or phone number.

Where is my workout data stored?

On your phone. Workout records, InBody results, set photos and videos stay in the app. Your workouts leave the phone only if you agree to the AI analysis. Then the last 8 weeks of workout numbers go to ArchiFit's server, which writes the analysis and stores nothing. The app also downloads the exercise list, and that request carries nothing that identifies you.

How does ArchiFit pick the next weight?

From the set you just logged and your plan's rep range (6–8 or 12–15). If the set went past the top of the range, the next set is one step heavier, about 5% and at least the exercise's weight step, for the bottom of the range. Otherwise the weight stays and the reps stay inside the range. The phone works it out; nothing is sent. All the rules.

Does ArchiFit work in lb?

Yes. One setting switches the whole app between kg and lb. Phones whose region is the United States start in lb, and all others in kg. Suggested weights land on the lb step, so a 2.5 kg step becomes 5 lb.

What is the AI analysis, and is it optional?

It is the last page of the weekly report. Your phone looks through 8 weeks of sets for lifts stuck at one weight, reps rising at the same weight and similar patterns. If you agree, those numbers go to the server, where an AI model from Anthropic writes a few short paragraphs. Every number in them has to come from your log. It is optional: decline, and the rest of the app works the same.

Does ArchiFit work without an InBody sheet?

Yes. You can type the numbers in, or choose a plan without InBody by picking the direction, days per week, split and rep range yourself. Logging, the rest timer, records and the weekly report need no body data at all.

Is ArchiFit on Android?

ArchiFit is in review on Google Play (coming soon). The iPhone app is free on the App Store now.

Guides for training alone

Your next set, from your own numbers.

Get ArchiFit on the App StoreComing soon on Google Play

Last updated 2026-11-12 By ArchiFit

Sources

American College of Sports Medicine. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687-708. doi.org/10.1249/MSS.0b013e3181915670