Knowing a reliable leg press to squat conversion will help you decide how much weight you can safely use when moving from the leg press to squat.
(Or vice versa.)
So, in this article, I explain a simple way of converting leg press to squats, how accurate this conversion is, as well as reasons why the leg press is easier than squats.
Leg Press To Squat Conversion
Right off the bat, it’s important to clarify that there isn’t a universal one-size-fits-all multiplier we can use to convert leg press to squats, and I’m going to explain why later in this article.
However, we can use some basic trigonometry to work out roughly how much you can squat with respect to leg press.
(Don’t worry – you don’t need to understand the math as I’m going to do the calculations for you!)
Leg Press To Squat Conversion Calculation
If we compare the angles of force during leg press and squats, then we can see that they form a triangle.
To come up with our equation, we first need to define some variables.
- A = the angle of the leg press
- Sf = the force of the squat
- Lf = the force of the leg press
- Bw = the weight of the person
Using trigonometry, we know that Sin(A) = Sf/Lf, or in other words, Lf x Sin(A) = Sf.
If we assume that you’re exercising on a standard 45-degree leg press machine, then A = 45, so we get Lf x Sin(45) = Sf.
Sin(45) = 0.7071 and therefore Lf x 0.7071 = Sf.
Another important consideration is that during squats, you’re not only pushing the weight on the barbell but you’re also pushing roughly 65% of your total bodyweight too.
So now, our equation becomes:
Lf x 0.7071 = Sf + (0.65 x Bw)
Now that we know the equation, let’s do a quick example with some values.
Let’s say a person who weighs 180lbs can leg press 500lbs.
This means that Lf = 500 and Bw = 180.
To know roughly how much they can squat, we just need to perform the below calculation.
Sf = Lf x 0.7071 – (0.65 x Bw)
Sf = 500 x 0.7071 – (0.65 x 180) = 237.
In other words, a 180lb person who can leg press 500lbs can squat approximately 237lbs.
How Accurate Is The Leg Press To Squat Conversion?
The leg press to squat conversion is fairly accurate.
The first part of the equation which involves converting the force of the leg press to the force of the squat is 100% accurate as it’s verified by a proven mathematical formula.
Where it gets tricky, however, is factoring how a person’s bodyweight affects the calculation.
While we used 65%, this is a rough estimate.
In reality, the range is likely between 60% and 75% depending on how tall the individual is.
This is because a short person will lift a smaller percentage of their bodyweight than a tall person during squats.
So, if you’re short, you could replace the 65% with 60% in your calculation.
Whereas if you’re tall, you could replace the 65% with 75%.
It’s worth noting, however, that this small margin of error doesn’t invalidate the accuracy of the conversion.
As a rule of thumb, it’s accurate to the nearest 10lbs.
Why Can I Leg Press More Than Squat? Why Is Leg Press Easier Than Squat?
As we can see from the calculation, you can leg press twice as much weight (and possibly even more) than you can squat.
Buy why is that the case?
Here are 4 reasons.
As explained earlier, the angle of the leg press machine makes the exercise much easier.
This is because when you squat, you’re pushing the mass against the gravitational forces in a vertical motion. Since gravity is a vertical force, you’re pushing against the full weight of the mass.
However, when you’re pushing the mass on a leg press machine, you’re not feeling the full effects of gravity since the motion is diagonal.
This effectively reduces the weight of the exercise.
(This is explained by the first equation from earlier: Leg Press Force x 0.7071 = Squat Force)
Squats Are A Compound Exercise
While the leg press works mainly your quads and glutes, squats work your lower body as well as your erectors, and upper body.
If you have really strong quads and glutes, but have weak core muscles, then you likely won’t be able to squat very much as your core will reach failure before your legs.
Whereas since the leg press only works your legs, then there’s minimal chance of other muscle groups fatiguing first.
As covered earlier, when you squat, you don’t just push the weight on the barbell – you push some of your bodyweight too.
Whereas leg presses don’t involve pushing any bodyweight.
Since your upper body doesn’t move during leg press, your height is irrelevant.
However, with squats, your height has a great impact on the difficulty of the exercise.
A tall person has longer internal levers, meaning that they must exert more force than a shorter person moving the same distance.
(This is why squats can be harder if you’re a tall person.)
- Leg press to squat conversion can be accurately calculated by the following equation: Sf + (0.65 x Bw) = Lf x 0.7071
- Squats are harder than leg press because you have to push more weight even with the same mass, and they rely on other weaker muscle groups which can fatigue before your leg muscles do.
That’s all for this article, but what about doing leg press after squats?
Hope this helped!
I’ve been in the fitness and strength training industry for nearly a decade. In that time, I’ve gained 30 pounds of muscle, written hundreds of articles, and reviewed dozens of fitness supplements. As for my educational background, I’m a currently studying for my Active IQ Level 3 Diploma in Personal Training.