Is there a maximum size parcel you can send through the post office?

Question

my parcel is a large box sending to the uk 29inches (L) 20inches (w) 8inches (h)

(i've put this question in the business section as i thought i might get the best answers here)

Answer 1

Go to the International postage calculator of USPS http://ircalc.usps.gov/ to estimate the cost of your package.

The size you gave is acceptable, though you have one missing information -- the weight of the package

Answer 2

Yes there is. According to the Royal Mail website, for their Standard Parcels service:

"You can send parcels up to 20kg in weight. Parcels must be no longer than 1.5 metres, and the combined length and girth of your item must not exceed 3m."