The cost of USPS flat-rate shipping

ewmayer · 2012-04-05, 19:42

An easy, but amusing "spot the outlier" problem. The US postal service has for nearly a decade offered a very popular flat-rate shipping option for priority (and other kinds) of mail. I use the FR boxes - mostly the medium, occasionally the large - all the time. Recently I had a smaller set of items to ship, so I looked into the small flat-rate box, which costs slightly less than half the medium-box rate. I figured the volume ratio of those 2 boxes should thus be roughly proportional to the cost ratio, which should allow my items, needing roughly one-third the volume of a medium-sized box, to fit into a small box. Not even close. Hence the resulting puzzle problem.

Using domestic priority mail and the in-store costs in the above-linked table, compute the shipping cost per cubic foot (use the internal box dimensions) of the 4 flat-rate boxes: small, 2 types of medium, large. Based on cost-per-volume, which is the best value? Which deserves the appellation "blatant rip-off"?

frmky · 2012-04-05, 21:15

I would disagree. I imagine the cost includes a fixed overhead plus a charge per volume. Plotting the cost vs volume for both sized medium and large boxes and performing a linear extrapolation leads to an expected cost of about $4.92 for the small box, which is reasonably accurate. The fixed overhead then appears to be around $3.85 per box.

ewmayer · 2012-04-06, 18:15

What "overhead" might that be? If you're going to justify $4 just for the starting price sans shipping cost, I want specifics, especially as that is nearly 10x the cost of a first-class letter, which presumably also involved many of your claimed "overhead" expenses.

Fusion_power · 2012-04-07, 00:16

First class letters do not have the same fixed costs as packages. They are handled by machinery vs the packages which require hands on. Compare apples to apples pls.

I ship hundreds of 1 cubic foot boxes per year with tomato and pepper plants. It is easy for me to estimate shipping to just about anywhere in the U.S. But I am lazy and I really prefer accurate shipping so I wrote a macro in Excel that looks up the shipping cost in the U.S.P.S. database and pops it into a cell in the spreadsheet. Please note that this is using priority mail shipping, not the flat rate boxes. Just to give you another "outlier", try shipping anything that is over 12 inches per side (total L + W + H > 36 inches) and see what it costs.

DarJones

2012-04-05, 19:42	#1
ewmayer ∂²ω=0 Sep 2002 República de California 5·2,351 Posts	The cost of USPS flat-rate shipping An easy, but amusing "spot the outlier" problem. The US postal service has for nearly a decade offered a very popular flat-rate shipping option for priority (and other kinds) of mail. I use the FR boxes - mostly the medium, occasionally the large - all the time. Recently I had a smaller set of items to ship, so I looked into the small flat-rate box, which costs slightly less than half the medium-box rate. I figured the volume ratio of those 2 boxes should thus be roughly proportional to the cost ratio, which should allow my items, needing roughly one-third the volume of a medium-sized box, to fit into a small box. Not even close. Hence the resulting puzzle problem. Using domestic priority mail and the in-store costs in the above-linked table, compute the shipping cost per cubic foot (use the internal box dimensions) of the 4 flat-rate boxes: small, 2 types of medium, large. Based on cost-per-volume, which is the best value? Which deserves the appellation "blatant rip-off"? Last fiddled with by ewmayer on 2012-04-05 at 19:44

2012-04-05, 21:15	#2
frmky Jul 2003 So Cal 2,621 Posts	I would disagree. I imagine the cost includes a fixed overhead plus a charge per volume. Plotting the cost vs volume for both sized medium and large boxes and performing a linear extrapolation leads to an expected cost of about $4.92 for the small box, which is reasonably accurate. The fixed overhead then appears to be around $3.85 per box. Last fiddled with by frmky on 2012-04-05 at 21:17

2012-04-07, 00:16	#4
Fusion_power Aug 2003 Snicker, AL 2⁶×3×5 Posts	First class letters do not have the same fixed costs as packages. They are handled by machinery vs the packages which require hands on. Compare apples to apples pls. I ship hundreds of 1 cubic foot boxes per year with tomato and pepper plants. It is easy for me to estimate shipping to just about anywhere in the U.S. But I am lazy and I really prefer accurate shipping so I wrote a macro in Excel that looks up the shipping cost in the U.S.P.S. database and pops it into a cell in the spreadsheet. Please note that this is using priority mail shipping, not the flat rate boxes. Just to give you another "outlier", try shipping anything that is over 12 inches per side (total L + W + H > 36 inches) and see what it costs. DarJones Last fiddled with by Fusion_power on 2012-04-07 at 00:16

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2012-04-06, 18:15	#3
ewmayer ∂²ω=0 Sep 2002 República de California 5·2,351 Posts	What "overhead" might that be? If you're going to justify $4 just for the starting price sans shipping cost, I want specifics, especially as that is nearly 10x the cost of a first-class letter, which presumably also involved many of your claimed "overhead" expenses.