3PL Peak Season Storage: Two Schedules, Two Different Fees

Search for peak season storage and you get a range: 15% to 30% surcharges, no vendor named, no schedule reproduced. That range is not wrong so much as unusable, because the two operations that actually publish a Q4 storage schedule do not charge a surcharge in the same sense of the word, and the difference decides what you should do about it in September.

We track 23 fulfillment operations. Two publish a peak-season storage schedule you can read without a login: Flexport Fulfillment and Walmart WFS. Their headline multipliers are almost identical — 2.96× and 3.0×. The mechanisms behind those two numbers have almost nothing in common.

The two published peak schedules

	Jan–Sep	Oct–Dec	multiplier	unit as published
Flexport Fulfillment	$0.81	$2.40	2.96×	per cubic foot per 30 days
Walmart WFS, first 30 days	$0.75	$0.75	1.0×	per cubic foot per month
Walmart WFS, beyond 30 days	$0.75	$2.25	3.0×	per cubic foot per month

Walmart’s own page states the peak figure as a composition rather than a rate: $0.75 base plus a $1.50 surcharge. That phrasing is the tell, and it is reproduced in our dataset’s conditions column because it is the part that matters.

Note the units differ even here. Flexport bills per 30 days; Walmart bills per month. Over a year that is 12.17 Flexport periods against 12 Walmart months — about 1.4% more billing periods, which is too small to change a decision and too real to leave unsaid.

A rate change and an aging trigger are not the same fee

Flexport’s Q4 storage is a rate change. On 1 October every cubic foot you are holding costs 2.96× what it cost on 30 September. Nothing about how fast you turn that inventory changes the rate. The only lever is volume.

Walmart’s is an aging trigger that happens to live inside peak. The first 30 days of Q4 storage cost exactly what September cost — $0.75, unchanged. The $1.50 surcharge attaches only to inventory that is still sitting there after 30 days. The rate is not really seasonal at all; it is a dwell-time penalty that only exists during the season.

So two schedules with a ~3× multiplier ask you for opposite things:

• Against Flexport, reduce how much you hold in Q4. Turning inventory faster does not help.
• Against Walmart, reduce how long you hold it. Holding less does not help proportionally — holding it briefly does.

A brand that reads “peak storage triples” and responds by cutting its Q4 buy is doing the right thing at Flexport and possibly the wrong thing at Walmart, where the same units turned inside 30 days never attract the surcharge at all.

400 cubic feet in September, 700 in November, priced three ways

Our worked profile holds 400 cubic feet off-peak and 700 at the November peak. That is the same profile used throughout the normalization method, and the arithmetic below is ours, applied to published rates.

September, 400 cubic feet:

Flexport	Walmart WFS	Amazon (see caveat below)
400 × $0.81 = $324.00	400 × $0.75 = $300.00	400 × $0.78 = $312.00

November, 700 cubic feet:

	November storage
Flexport	700 × $2.40 = $1,680.00
Walmart, turned inside 30 days	700 × $0.75 = $525.00
Walmart, still held past 30 days	700 × $2.25 = $1,575.00

The Walmart row is the finding. The same 700 cubic feet, in the same warehouse, in the same month, costs either $525 or $1,575 — a $1,050 difference decided by dwell time alone, which is 700 × the $1.50 surcharge exactly. No vendor negotiation produces that spread. Operations does.

Read as a September-to-November multiple: Flexport goes up 5.19×, Walmart either 1.75× or 5.25×. The fast-turning Walmart brand and the slow-turning one are not on the same rate card in any meaningful sense, and a quote comparison that prices only the headline peak rate will tell the fast one something false.

Across the full quarter — 700 cubic feet in October, 700 in November, 450 in December, so 1,850 cubic-foot-months — the peak schedule costs Flexport $4,440.00 against $1,498.50 at its non-peak rate: $2,941.50 of pure seasonality. Walmart’s worst case is $2,775.00 more than its own base, and its best case is zero.

What we cannot tell you cleanly, and the gap is ours

Amazon is the largest player here and the honest answer is layered.

The $0.78 used above is Amazon’s non-peak standard-size rate, confirmed effective 1 April 2024, and it is a real row in our dataset.

The peak figure is a different matter. Amazon’s public supply chain rate card prints January–September at $0.78 and October–December at $2.40 per cubic foot for standard size ($0.56 and $1.40 for bulky and extra large) — read 17 August 2026. That is a 3.08× multiplier, the steepest of the three, and structurally it is a rate change like Flexport’s rather than an aging trigger like Walmart’s.

But that figure is not yet a row in our dataset. Our Amazon storage table row is still marked QUOTE_GATED, dated from when we believed the current table was reachable only behind a login. It is not: it is on the public card cited above, in the same PDF we already cite for fulfilment fees. We found that on 17 August while correcting an unrelated error, and the dataset has not yet caught up with the finding.

We are stating this rather than quietly using the number, because the whole proposition here is that every figure has a row and a source behind it, and this one currently has a source but not a row. It is queued for the next dataset release. Until then, treat Amazon’s $2.40 as sourced-but-unindexed — good enough to plan against, not yet good enough for us to count.

Amazon’s aged inventory table remains genuinely QUOTE_GATED and we are not going to guess at it.

Aged storage is a third mechanism, and it outlasts the season

Peak surcharges end on 31 December. Aged-inventory surcharges do not, and they are steeper:

	tier	rate
Walmart WFS	366–450 days	$2.25 per cubic foot per month
Walmart WFS	over 450 days	$7.50 per cubic foot per month
Flexport	365+ days	$6.90 per cubic foot per 30 days, minimum $0.15 per unit per 30 days

Walmart’s over-450-day rate is 10× its base, and it is the same $2.25 figure at 366–450 days that appears in its peak-season row — the same number reached by two unrelated mechanisms, which is exactly the kind of coincidence that gets misread as one rule.

The Q4 inventory you do not sell becomes the aged inventory you pay for in the spring. That is one decision, made in September, that shows up on two different fee lines eleven months apart.

One more line that catches small SKUs

Flexport applies a minimum storage charge of $0.10 per DSKU per day, and its conditions state this floor applies in both seasons. For a brand carrying many low-volume SKUs, that floor can exceed the cubic-foot arithmetic entirely — 100 slow SKUs is $10.00 a day, or roughly $300 a month, whatever their footprint. Off-peak that is the larger number for a small catalogue. It is also the line most often left out of a peak-season comparison, because it is not a peak-season line.

What to do in September

1. Establish which mechanism you face. Ask the vendor, in writing: is your Q4 rate a rate change from 1 October, or a surcharge on inventory held beyond a stated number of days? The two answers lead to different plans, and the question is short enough that a vague answer is itself an answer.
2. If it is a rate change, the lever is your Q4 footprint. Price your October–December plan at the peak rate, not the blended one.
3. If it is an aging trigger, the lever is dwell time. Model the 30-day boundary explicitly: on our profile it is worth $1,050 in a single month.
4. Get the aged-inventory table at the same time. It is the same conversation and it prices the Q4 you do not sell.
5. Check for a minimum or floor that applies regardless of season.

The contract red-flag checklist covers the clause language that lets a peak definition move after signature.

Limitations

• Two of 23 operations publish a peak storage schedule as an indexed row. Everyone else either does not publish one or does not distinguish the season.
• Amazon’s peak figure is cited from its public rate card but is not yet a dataset row. See above. Amazon’s aged-inventory table is not public.
• The 400 and 700 cubic-foot figures are our worked profile, not yours. The multipliers are published; the dollar totals are our arithmetic on your behalf and change entirely with footprint.
• Flexport bills per 30 days, Walmart per month. We have not converted between them; both are reproduced in their published unit.
• We have not verified how any of these vendors measures your cubic footage, which is upstream of every number on this page.

If any figure here disagrees with the vendor’s page on the date you read it, that is worth an email to data@ratecardlab.com — corrections are published at /corrections/.

Figures are quoted from the vendor’s own page on the date given and cross-checked against our dataset. The unit column is reproduced verbatim, including where a vendor’s unit is less specific than we would like. Where we do arithmetic on a published figure rather than reporting it, the sentence says so.

Sources

Every row behind this page, with its source URL and the date it was read, is in the fee benchmark table. The storage rows specifically are also compared by unit in Storage Fees: Cubic Foot vs Pallet, which covers the denominator problem this page assumes.

If you are pricing a full quote rather than a storage line, the 3PL Quote Normalizer Kit carries a twelve-month projection that prices peak storage separately from peak volume — which, as this page argues, are two different questions.

Who publishes storage rates

5 of the 7 providers whose rate cards we hold publish storage rates outright. Each page below lists every fee that provider publishes, with the source URL and the date we read it.

• Flexport 15 published storage rates · 75 fees in total
• Walmart WFS 5 published storage rates · 26 fees in total
• Fulfyld 4 published storage rates · 12 fees in total
• ShipCalm 2 published storage rates · 35 fees in total
• Simple Global 2 published storage rates · 8 fees in total

All published fees by vendor · What a 3PL costs in 2026