# FreeRTOS heap size define !

**URL:** <https://forums.freertos.org/t/freertos-heap-size-define/4133>\
**Category:** Kernel\
**Created:** [December 17, 2013, 12:55pm UTC](https://forums.freertos.org/t/freertos-heap-size-define/4133 "2013-12-17T12:55:13Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [December 17, 2013, 12:55pm UTC](https://forums.freertos.org/t/freertos-heap-size-define/4133/1 "2013-12-17T12:55:13Z")

</div>

**[vicui](https://sourceforge.net/u/vicui/)** wrote on [Tuesday, December 17, 2013](https://sourceforge.net/p/freertos/discussion/382005/thread/b6f1d7c3/#9a95):

Hi:

my all task stack size \* 4 is 25600 Byte in my system.  
if I define FREERTOS heap size is 30KByte, all task is created successfully, but some task can’t work.  
if I define FREERTOS heap size if 31KByte, all task is created successfully, and all task work well.  
except task stack size is malloc from freertos heap, is there other memory from freertos heap ?

vincent

---

<div class="post-metadata">

**Author:** ![richard-damon](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/richard-damon/32/38_2.png) [@richard-damon](https://forums.freertos.org/u/richard-damon)\
**Post date:** [December 17, 2013, 1:06pm UTC](https://forums.freertos.org/t/freertos-heap-size-define/4133/2 "2013-12-17T13:06:41Z")

</div>

**[richard\_damon](https://sourceforge.net/u/richard_damon/)** wrote on [Tuesday, December 17, 2013](https://sourceforge.net/p/freertos/discussion/382005/thread/b6f1d7c3/#985f):

In addition to the stacks, FreeRTOS also allocates the Task Control Blocks, and all Queue, Semaphores and Mutexes on the heap.