Please make sure to read the common questions. If you are posting tracking info don't include your tracking number as it contains personal information. https://www.reddit.com/r/UPS/about/sticky?num=1 I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns. More on reddit.com

I did round up on everything Accuracy is the key here. You have to understand that many large packages will bow out slightly during transit and may move your measurements up. Be sure to double check everything and give a slight allowance for this. Especially on larger/heavier packages where it's most likely to happen. More on reddit.com

A computer tries to formulate an efficient route ever day based on what addresses have packages that day. It tries to save gas by making the route as short as possible. But the computer (or the programmer that wrote the code) has never actually done the job, so it doesn't know about all the little things that the driver does, like: You can't actually make a U-turn in the middle of a residential street. You can't park on a four lane rode with no curb and deliver to the other side of the street. Or the tail end of the route has a few commercial stops and needs to be delivered before 5pm so the middle part of the route can wait. The driver does know these things and adjusts his route accordingly (much to the dismay of the people that paid a bunch of money for a broken computer program). More on reddit.com

I've found the calculator to be very accurate (for both UPS and FedEx) IF you measure & weigh correctly. UPS was only added to eBay fairly recently and I've been auditing my shipments exactly to ensure no upcharge 'gotchas'. So far entirely accurate. By 'measuring correctly' I mean realize that 37.01" x 19.01" x 2.01" and 11.01 lbs should be entered as 38x20x3 @ 12 lbs. Similarly, be careful of 'irregular' sizes: if your package is 38x20 but one end is 3" high and the other is 2" high, that's 38x20x3 - you don't take the 'average' or anything. Another 'gotcha' is if you buy or get boxes with the 'size' printed on them, that's the INTERNAL dimensions. So if you take a box that says "12x12x12" and ship it using "12x12x12" as the dimensions, you're likely to get hit with an 'upcharge' for a 13x13x13 box... Also realize that the UPS charges the greater-of actual weight or 'dimensional' weight (based on size). So if a 0.1" or 0.1 lb difference you didn't include puts you from one into the other, charges can go up notably: basically you're jumping to a higher rate-tier. Also, if you ship a box that ends up bigger or heavier than UPS Ground actually handles, there's not just higher shipping fees, but a 'penalty' fee as well... So if you're mailing a box that's 149.9lb make DAMNED sure your scale is accurate, because if it's actually 150.1 lbs, you could face some SERIOUS upcharges. Given all the above, I've found IF you put in the truly-correct information, the calculated cost is very accurate. There do seem to be some legit horror-stories about folks getting whacked with completely overstated charges. But MOST of the ones I've seen where real info eventually got provided, it turned out to be mismeasurement and/or 'hoping to slide one by'... More on reddit.com