One Rep Max for 45 lbs × 4 reps

One Rep Max Calculator
One Rep Max for
lifted for
reps

What is the one rep max for 45 lbs × 4 reps?

Answer

Lifting 45 lbs for 4 reps gives an estimated one rep max of
51 lbs

A set of 4 reps at 45 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:

45 × (1 + 4 ÷ 30)

≈

45 × 1.1333

≈

51 lbs

Training Weights as a % of 1RM

Percentages of your estimated max of 51 lbs, the way most strength programmes prescribe load:

% of 1RMWorking Weight
95%48.5 lbs
90%45.9 lbs
85%43.4 lbs
80%40.8 lbs
75%38.3 lbs
70%35.7 lbs
65%33.2 lbs
60%30.6 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 45 lbs × 4 reps:

FormulaEstimated 1RM
Epley51 lbs
Brzycki49.1 lbs
Lombardi51.7 lbs
O'Conner49.5 lbs
Wathan51 lbs
Lander49.7 lbs
Mayhew52.4 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 45 lbs × 4 reps? (The answer is: 51 lbs). Enter the weight you lifted (e.g. 45), pick pounds or kilograms, and enter how many reps you managed (e.g. 4).
Recalculate with different values ↑

One Rep Max Table for 45 lbs

RepsOne Rep Max% of 1RM
2 reps48 lbs93.8%
3 reps49.5 lbs90.9%
4 reps51 lbs88.2%
5 reps52.5 lbs85.7%
6 reps54 lbs83.3%
7 reps55.5 lbs81.1%
8 reps57 lbs78.9%
9 reps58.5 lbs76.9%
10 reps60 lbs75%
11 reps61.5 lbs73.2%
12 reps63 lbs71.4%

FAQ

What is the one rep max for 45 lbs × 4 reps?

Lifting 45 lbs for 4 reps gives an estimated one rep max of 51 lbs

How much of my max is 45 lbs for 4 reps?

45 lbs for 4 reps works out at 88.2% of an estimated one rep max of 51 lbs.

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

90% of 51 lbs is 45.9 lbs and 70% is 35.7 lbs. Heavy strength work usually sits at 85–95%, while volume and technique work sits nearer 65–75%.

See Also