From XL Help ("Specifications"):

Largest amount of time that can be entered 9999:99:99

Calculated times can be larger (at least 66600000:00:00.

In article ,
Stefi wrote:

Hi All,

[h]:mm time format seems to work only up to 9999 hours, XL2003 doesn't
handle 10000 hours as time, 10000:00 remains text. Is this an unchangeable
limit?

Thanks,
Stefi