One Rep Max for 390 lbs × 4 reps

One Rep Max Calculator

One Rep Max for

lifted for

reps

What is the one rep max for 390 lbs × 4 reps?

Answer

Lifting 390 lbs for 4 reps gives an estimated one rep max of
442 lbs

A set of 4 reps at 390 lbs is

88.2%

of your estimated one rep max

Note: this is an estimate, not a tested max. Rep-based formulas are closest at 2–6 reps and drift further apart as the set gets longer. Warm up and use a spotter before attempting a true single.

How to Calculate One Rep Max

Epley Formula: 1RM = weight × (1 + reps ÷ 30)

The Epley formula assumes that every extra repetition you can complete corresponds to roughly 3.33% more weight on the bar. Put your set into it:

390 × (1 + 4 ÷ 30)

=

390 × 1.1333

=

442 lbs

Training Weights as a % of 1RM

Percentages of your estimated max of 442 lbs, the way most strength programmes prescribe load:

% of 1RMWorking Weight
95%419.9 lbs
90%397.8 lbs
85%375.7 lbs
80%353.6 lbs
75%331.5 lbs
70%309.4 lbs
65%287.3 lbs
60%265.2 lbs

Other One Rep Max Formulas

Published 1RM formulas disagree, and the gap widens with the rep count. This page answers with Epley; here is what the others give for 390 lbs × 4 reps:

FormulaEstimated 1RM
Epley442 lbs
Brzycki425.5 lbs
Lombardi448 lbs
O'Conner429 lbs
Wathan442.1 lbs
Lander430.4 lbs
Mayhew454.4 lbs

See Also

One Rep Max Calculator

This calculator estimates your one-rep max (1RM) — the heaviest weight you could lift for a single repetition — from a set you have already completed. For example, it can help you find out what is the one rep max for 390 lbs × 4 reps? (The answer is: 442 lbs). Enter the weight you lifted (e.g. 390), pick pounds or kilograms, and enter how many reps you managed (e.g. 4).

One Rep Max Calculator

One Rep Max for

lifted for

reps

One Rep Max Table for 390 lbs

RepsOne Rep Max% of 1RM
2 reps416 lbs93.8%
3 reps429 lbs90.9%
4 reps442 lbs88.2%
5 reps455 lbs85.7%
6 reps468 lbs83.3%
7 reps481 lbs81.1%
8 reps494 lbs78.9%
9 reps507 lbs76.9%
10 reps520 lbs75%
11 reps533 lbs73.2%
12 reps546 lbs71.4%

FAQ

What is the one rep max for 390 lbs × 4 reps?

Lifting 390 lbs for 4 reps gives an estimated one rep max of 442 lbs

How much of my max is 390 lbs for 4 reps?

390 lbs for 4 reps works out at 88.2% of an estimated one rep max of 442 lbs.

What should I lift at 90% and 70% of that max?

90% of 442 lbs is 397.8 lbs and 70% is 309.4 lbs. Heavy strength work usually sits at 85–95%, while volume and technique work sits nearer 65–75%.