Package Dimensions - is all that matters total cubic inches? - partial inch package dimensions

[alchemista]

eBay only lets you put in whole numbers for package dimensions and tells you to round up to avoid extra charges. However, I'd rather not round up if it's going to cost me more.

For example, if I have a package that is 13.25" x 11.25" x 6.25" (932 cubic inches) - if I round that up to 14 x 12 x 7 (1176 cubic inches) I end up with about a 30% extra rate over just entering 14x11x6 (924 cubic inches)

USPS I believe only cares about total cubic inches, is that correct? If so, then since eBay doesn't let you pick partial, shouldn't I instead enter whole dimensions that get me closest to the actual cubic volume? Like the example above?

[dryophelia]

@alchemista 

When the post office measures they add about half an inch. You’ll be watching the measurement end, but if you look at the other end, the ruler is overhanging the edge. 

[richard1rst]

Unless you are using the Cubic Price postage rate (which eBay does not offer) then as long as it is under one cubic foot (which both of your examples are) then it doesn't matter. In the 2 cases you cited the postage would be the same if the weight is the same. IF you are using USPS then 14x12x7 is NOT going to add 30% as it is UNDER one cubic foot which is the trigger for the extra charge.

If, however, you are using Cubic Pricing offered by Pirateship they do allow fractional measurements. HOWEVER in both of the cases you cite your packages are over 1/2 cubic foot in which case even the Cubic Pricing would be the same. So for the cases you cited it doesn't matter either way.

[nobody*s_perfect]

USPS policy for package volume is to enter the dimensions in whole inches after you round off, in which case your package would be measured as 13 x 11 x 6 because the fractions are less than 1/2.  As noted in the other post, for your particular example it doesn't make any difference  in the postage cost if you're shipping via USPS.

See 1.5.1: https://pe.usps.com/text/dmm300/223.htm

[johnrj1226]

With your examples  it won't change your shipping rate as neither one exceeded one cubic  foot or 1728 cu. in.   Your charge(s) would be based on weight and zone to  zone distance.   Above 1728 cu. in. is when the cubic rate kicks in.

[varebelrose]

I have never run into a situation where changing those dimensions so slightly would ever change the postage price at all, unless it went over the combined 130 inch length/girth oversize rule.  In my experience, it based on rate, but maybe things have changed. OP, can you provide some screenshots showing these prices changing by 30% at these size ranges? It would help to understand what is going on; wouldnt surprise me if the USPS has changed rules again.

[nobody*s_perfect]

Changing by one inch CAN make a difference, IF it puts the package over that 1728-cubic-inch threshold.  For instance, a 12-inch cube ships at the weight-based rate but a box that's 12x12x13 is over the threshold for "dimensional weight" and will ship at the 12-pound rate. That would be roughly a 30% increase if the actual package weight was about 7 pounds.  If the actual package weight was less, then the percentage increase would be even more. The cost of a 2-pound package to Zone 8 would more than triple.

Until a few years ago, USPS charged the dreaded "dimensional weight" only for Priority Mail packages that were going to Zones 5 - 8.  But now it is applied to all Priority Mail, Parcel Select Ground, and Retail Ground going to all Zones.

Retail Ground and Parcel Select Ground still have an Oversize rate for packages with a length-plus-girth above 108 inches (which is the maximum size for Priority Mail) up to 130 inches ,which is the maximum that USPS will accept.

In the example the OP gave, I think she applied the dimensional weight formula to her package although it's below the threshold.

[alchemista]

Sorry everyone, my example was just random numbers and I didn't mean to distract with specifics. My general question is whether the total volume matters instead of very accurate each dimension

Real example is:

actual package:

18.75 x 13.25 x 6.25 = 1552 - under the cubic ft

If I enter 19 x 14 x 7 = 1862 - over the cubic ft - blows up the shipping cost (actually more than doubles the standard priority mail)

If instead I put 19 x 14 x 6 = 1596, I'm under the cubic ft but over the actual volume

So hence my question - should I put 19 x 14 x 6, or whatever general adjustments in the future, to get closest to actual volume? Even though that is against eBay saying to round up.

[nobody*s_perfect]

I explained the USPS policy in post #4, applied it to your example, and even gave a link to it. 

In your new example, rounding off the dimensions gives 19x13x6 = 1482 cubic inches.

[alchemista]

Thank you - it seems like eBay should update their instructions, as the USPS "round off" is different than eBay's "round up" as described. USPS is doing "normal" rounding which makes much more sense.

[toysaver]

When I first started shipping I went to the PO and for the bigger boxes they used a seamstress' tape measure and started on one side and then without letting go of the last 'reading' added the second to the inches and finally the third to end up with one total number on the tape measure.   I decided from that the fractional measurements can be used as all the PO wanted was the end number.  I've adjusted my box sizes when listing to reflect the total and haven't had any cost price adjustments.  I assume they have a high speed laser that does the measuring.