My 13 year old Lab has fallen in love with her bed.  She cannot jump up on our bed anymore however she now has her own lovely bolster bed to sleep next to my side of the bed.  I kept wondering what size to buy - large or extra large.  I ordered the large and it is perfect.  She can curl up or lay all the way down in comfort with her head raised on the bolster.  She weighs 66 pounds and is 3 foot long from top head to tail bone laying down.  I hope this helps with others wondering what size to buy.  Great purchase at a great price!