> For the complete documentation index, see [llms.txt](https://docs.sevenpens.com/drawtab/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sevenpens.com/drawtab/core/pressure/maximum-physical-pressure.md).

# Maximum physical pressure

## Overview

Maximum physical pressure is the maximum amount of physical force a pen can uniquely detect.

## Video

If you would prefer to watch, see this video:

{% embed url="<https://www.youtube.com/watch?v=H87GUsU6Hh0>" %}

## Relationship to pressure range

Maximum physical pressure is the upper bound of the pen's pressure range. It is the logical opposite of the [IAF](/drawtab/core/pressure/iaf.md).

## What happens when physical pressure is more than the maximum

Suppose a physical force of 499gf makes the pen report a pressure level of 99.9%.

And then at 500gf, the pen will report 100% pressure. This means 500gf is the maximum physical pressure.

If the physical force is 501gf, the pen continues to report 100% pressure. In other words, when the pen reports 100% pressure, you do not know whether it is exactly at its maximum physical pressure. It could be at that value or at any value above it.

## What is a good maximum physical pressure

Generally, you want a pen with a high maximum physical pressure.

Anything at 350gf and above is good.

Anything at 500gf to 900gf is excellent.

Approaching 900gf makes it hard to reach 100% pressure.

## Can maximum physical pressure be too high?

Yes. Any pen with a maximum physical pressure of 900gf is very hard to press down to 100% pressure.

* Some people simply cannot press down that hard.
* Some people can press down that hard, but it is difficult or painful.
* Some people find it very tiring.

The good news is, you can artificially reduce maximum physical pressure with a pressure curve. See: [Lowering maximum physical pressure](/drawtab/guides/customizing/lowering-max-physical-pressure.md).

## Can maximum physical pressure be too low?

Yes.

When a pen has a maximum physical pressure of 200gf or less, it is easy to accidentally hit 100% pressure. This can make strokes look blotchy. People might describe the pressure as very hard to control.

## Variability in pens

The maximum physical pressure will vary between pen models.

However, be aware that even units of the same pen model can vary substantially in their maximum physical pressure.

For example, some pens might vary by +/- 50gf. This is considered very good because it is a low amount of variation.

Other pens might vary by +/- 200gf. This is considered a large amount of variation.

Low variation is desirable. It means that, if you replace a pen with another of the same model, you can expect the new pen to behave like the old pen in terms of maximum physical pressure.