C = arrayfun(@(x)rand(randi([1 20],1,2)),(1:8)','un',0);% example [s,d] = cellfun(@size,C); out = max([s,d]);

max(cellfun(@length, YourCell))

[max_size, max_index] = max(cellfun('size', B, 1))

This should work

A = {rand(2,3), rand(3,3), rand(2,4)}
% Find the maximum numbers rows (dims(1)) and the maximum number of columns (dims(2))
dims = max(cell2mat(cellfun(@(x)size(x), A, 'uni', 0)'));
%Pad each element of A with zeros so that it's size becomes dims
B = cellfun(@(x)[x,zeros(size(x,1),dims(2)-size(x,2));zeros(dims(1)-size(x,1),dims(2))], A,'uni', 0)

This results in

B = 

    [3x4 double]    [3x4 double]    [3x4 double]

And more specifically:

>> B{1}

ans =

    0.9028    0.5791    0.0366         0
    0.5763    0.0658    0.3373         0
         0         0         0         0

>> B{2}

ans =

    0.0764    0.1326    0.4413         0
    0.2463    0.0238    0.3726         0
    0.0299    0.2610    0.1408         0

>> B{3}

ans =

    0.6266    0.6141    0.5653    0.5951
    0.3176    0.0741    0.5795    0.2600
         0         0         0         0

>> c = {1 [1,2] [1,3] [1,2,4] [1,2,4,5] [1,6] [1,2,4,5,7] nan} c = [1] [1x2 double] [1x2 double] [1x3 double] [1x4 double] [1x2 double] [1x5 double] [NaN] >> [~,x] = max(cellfun(@numel,c)) x = 7

This issue could be due to RAM limitations. You may try the following suggestions: 1.Go to MATLAB > Preferences > Workspace and ensure the Maximum array size limit is set to 100%. Then execute 'memory' command in the Command Window and send the output. Ensure that the Maximum possible array size is larger than the memory required by the data. 2. Also, check that the Java Heap Memory is not set to a very large value because that might restrict the amount of memory available to perform computations.

Take a look at this page, it lists the maximum sizes: Max sizes

It looks to be on the order of a few hundred million. Note that the matrix you're trying to create here is: 10e6 * 10e6 = 10e12 elements. This is many orders of magnitude greater than the max sizes provided and you also do not have that much RAM on your system.

My suggestion is to look into a different algorithm for what you are trying to accomplish.

Yes, there is necessary overhead for cell arrays. Note that |whos| (which your |getsize| uses|) does not actually show all the memory used by variables. By necessity a cell array cannot just store the content of the data (your 2 bytes consumed by 'a'). It also needs to store: * where that content is actually stored in memory (since the content of the cell array can be anything, the content is not actually stored inside the cell array, just a pointer to the content) * the matrix header for that content which includes: * the type of content * how many dimensions that content has * the length of each dimension of that content This result in an overhead of 112 bytes per non-empty cell (empty cells only need 8 bytes to store a null pointer) To that you need to add more bytes that |whos| doesn't show and that are required for every variable in matlab: * the type of the variable (i.e it's a cell array) * how many dimensions that variable has * the length of each dimension

My original answer returned the maximum element of the cell. Now including your comments the right code:

knedlsepp basically got it. Minor improvement in performance:

[a(:,1),a(:,2)]=cellfun(@size,A);
max(a)