Strength · Tool 5 of 5
Working Weight Calculator
You do not need to test a true one-rep max to program your training. A set you already did close to failure gives you an estimate that is good enough for choosing working weights, and it does not cost you a week of recovery or an injury.
Tell me about the set
Why two formulas instead of one
Epley and Brzycki are the two most widely used estimates and they disagree slightly, in opposite directions, depending on the rep count. Averaging them is not more scientific — it just avoids inheriting the specific bias of either one.
The input that decides accuracy
Everything depends on the set you enter being genuinely close to failure. A set of 5 you could have taken to 8 produces an estimate that is far too low, and then every working weight derived from it is too light. If you are not sure, treat the output as a floor.
Re-test rather than recalculate
Estimated maxes go stale — a beginner outgrows the number in weeks, an experienced lifter in months. Re-enter a real set every four to six weeks and let the working weights move with it.
If you are lifting in a deficit
Expect the estimate to stall or drift down late in a fat loss phase. That is normal. What you should not do is keep chasing records into week ten of a deficit. See strength training while in a calorie deficit.
Questions I get asked
Do I have to test a true 1RM?
No, and for most people you should not. A true max attempt carries real injury risk and costs recovery, to produce a number an estimate would have given within a few per cent.
Why does the estimate get worse at high reps?
Above roughly 10 reps the limiting factor shifts from maximal force production toward muscular endurance, which varies far more between people.
Does this work for every lift?
Best for compound barbell lifts — squat, bench, deadlift, overhead press. Less reliable on isolation work and machines.
Should I train to failure?
Rarely, and not on compound lifts as a default. Leaving one to three reps in reserve gives most of the stimulus with far less fatigue.
Read next
- How to Estimate Your 1RM Without Testing a Max Testing a true one-rep max costs recovery and carries risk. A set you have already done gives you an estimate that is good enough to program from.
- Picking Your Working Weight for Any Rep Scheme How percentages of your max map to rep ranges, why reps in reserve beats training to failure, and how to warm up to a top set without wasting it.
- Strength Training While in a Calorie Deficit What to expect from your lifts during a fat loss phase, what to change in the programme, and which numbers you should stop chasing entirely.