One Rep Max for 400 lbs × 8 reps

One Rep Max Calculator
One Rep Max for
lifted for
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What is the one rep max for 400 lbs × 8 reps?

Answer

Lifting 400 lbs for 8 reps gives an estimated one rep max of
506.7 lbs

A set of 8 reps at 400 lbs is

78.9%

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:

400 × (1 + 8 ÷ 30)

≈

400 × 1.2667

≈

506.7 lbs

Training Weights as a % of 1RM

Percentages of your estimated max of 506.7 lbs, the way most strength programmes prescribe load:

% of 1RMWorking Weight
95%481.3 lbs
90%456 lbs
85%430.7 lbs
80%405.3 lbs
75%380 lbs
70%354.7 lbs
65%329.3 lbs
60%304 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 400 lbs × 8 reps:

FormulaEstimated 1RM
Epley506.7 lbs
Brzycki496.6 lbs
Lombardi492.5 lbs
O'Conner480 lbs
Wathan512.8 lbs
Lander500.4 lbs
Mayhew505.1 lbs

Related Calculations

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 400 lbs × 8 reps? (The answer is: 506.7 lbs). Enter the weight you lifted (e.g. 400), pick pounds or kilograms, and enter how many reps you managed (e.g. 8).
Recalculate with different values ↑

One Rep Max Table for 400 lbs

RepsOne Rep Max% of 1RM
2 reps426.7 lbs93.8%
3 reps440 lbs90.9%
4 reps453.3 lbs88.2%
5 reps466.7 lbs85.7%
6 reps480 lbs83.3%
7 reps493.3 lbs81.1%
8 reps506.7 lbs78.9%
9 reps520 lbs76.9%
10 reps533.3 lbs75%
11 reps546.7 lbs73.2%
12 reps560 lbs71.4%

FAQ

What is the one rep max for 400 lbs × 8 reps?

Lifting 400 lbs for 8 reps gives an estimated one rep max of 506.7 lbs

How much of my max is 400 lbs for 8 reps?

400 lbs for 8 reps works out at 78.9% of an estimated one rep max of 506.7 lbs.

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

90% of 506.7 lbs is 456 lbs and 70% is 354.7 lbs. Heavy strength work usually sits at 85–95%, while volume and technique work sits nearer 65–75%.

See Also