Kufu
How the estimate works
No formula is exact, but two hold up well in the range people actually train in. This calculator uses the one that fits your rep count:
7–12 reps (Epley): 1RM = weight × (1 + reps ÷ 30)
Both are usually within about 5% of a tested max between 2 and 10 reps, and drift quickly above that. That's why the calculator stops at 12 reps: a 20-rep set says more about your endurance than your max, and a wrong number here would turn into a wrong training weight.
The table runs the same formula backwards, so each row is the load you could expect to manage for that many reps when fresh. Working sets usually sit one to three reps short of that.
Weighted pull-ups and dips
On a pull-up you lift your whole body plus the plate. A 1RM for "+20 kg" means nothing unless your bodyweight is in it. In bodyweight mode the calculator:
- adds your bodyweight to the added weight to get the total load,
- estimates the 1RM of that total,
- takes your bodyweight back off, so the answer is what to hang on the belt.
When a rep target needs less than your bodyweight, the table says so: that's a target for an assisted variation or a slower tempo, not more plates.
Example: at 80 kg bodyweight, 8 pull-ups with +10 kg is a total of 90 kg × 8, an estimated 114 kg total, so about +34 kg for a single: +35 kg once rounded to 2.5 kg plates.
Same math as the app
This is the formula the Kufu app uses to set the next session's weight. When no set held the target reps, it converts your best set through the estimated 1RM and back. Kufu programs pull-ups and dips as main lifts beside the barbell, with weighted versions as the progression.
FAQ
Should I test my 1RM?
You don't need to. An estimate from a hard set of 3–8 reps is safer and accurate enough to program from. If you do test, warm up well and use a spotter or safeties.
Why does my estimate change between rep counts?
People differ in endurance. Some people can do 10 reps at 75% of their max, others 6. Your own best sets at several rep counts will tell you which way you lean.