TikTok Shop FBT Restock Timing: How Much to Send, and How Often

Restock decisions usually get made on freight economics: a bigger shipment spreads the cost of sending it across more units, so bigger looks cheaper on the spreadsheet. That reasoning is fine right up to the point where the warehouse starts charging for time, and FBT starts charging for time on day 61.

This page is the counterpart to the one on dead stock, which asks whether to discount inventory that has already gone slow. This one asks the earlier question: given a rate card that is free for 60 days and then climbs, how much should you send in the first place, and how often? The eight rates, the daily basis and the age formula are TikTok’s, from the FBT Rate Card. The restock model built on them is ours, and is labelled where it starts.

The free window is 60 days per unit, not per month

Three things about the window are worth being precise about, because all three get misread.

• It runs per unit. TikTok states that “storage fees for inventory held for the first 60 days will remain free.” A unit’s clock is its own.
• It does not refill. There is no monthly allowance that resets on the first of the month. Day 61 is day 61 regardless of what the calendar says.
• A new shipment does not reset old stock. TikTok defines age as “Storage Days = Outbound Time − Inbound Time.” New units start a new clock; the batch already sitting there keeps ageing. That last point is our reading of the formula, not a separate statement from TikTok.

So the free window is not a discount you earn periodically. It is a runway each unit gets once, and the whole restock question is whether your batch fits inside it.

What it costs once the window closes

Eight tiers, effective December 15, 2025, in dollars per cubic foot per day:

Storage is calculated daily at 23:59 on the total cubic feet of all your units, “including both sellable and defective units.” The minimum chargeable volume is 0.001 cubic feet per SKU per day, which only affects items smaller than about 1.7 cubic inches.

Two costs pull in opposite directions

Sending a shipment has a fixed cost — freight, prep, the hour of work — call it F. The more units you put in it, the less that cost lands on each one. Against that, the longer a batch sits, the more of it ages past day 60 and starts billing at a rate that keeps rising.

Put those on one axis and the model is small. If you sell D units a day and send Q at a time, the batch is in the warehouse for T = Q/D days, and the last unit of it has been sitting for exactly that long when it sells. Every unit gets the same treatment, so:

Storage per unit = unit volume (cu ft) × the tier schedule summed from day 1 to day T

and the cost you are trading against it is simply F/Q. Total cost per unit is the sum. Storage is zero as long as T stays at or below 60, which is the whole reason the free window is worth planning around.

What this model assumes. Sales are steady and units sell in the order they arrived; you replenish the moment a batch runs out; the warehouse holds a full batch’s worth of stock at all times. Real demand is lumpy and seasonal, and a batch that sells unevenly will always have some units sitting longer than T. The tier schedule and the age formula are TikTok’s; the steady-sales assumption, the labelling fee F and every number that follows from them are ours.

Worked example: 10 units a day

Take a product in a 12×10×8 in box — 960 in³, or 0.556 cu ft a unit — selling 10 units a day, with $120 of fixed cost every time you send a shipment. Each row is one possible batch size:

The cheap point is 600 units — exactly 60 days of sales — and it is not a close call. Going from 600 to 900 saves $0.07 a unit of freight and costs $0.50 a unit of storage. Going to 1,200 saves another $0.03 and costs $1.17. The freight saving shrinks as the batch grows while the storage cost accelerates, so past the free window every extra unit is a bad trade in this example.

Note also how badly the tail scales. A 2,700-unit batch pays $24,750 in storage to save $0.16 a unit in freight, which is $432 of freight saved against $24,750 of storage incurred.

How expensive would shipping have to be to justify a bigger batch?

The answer is a number, and it is larger than most sellers assume. Holding the product and the sales rate fixed, a 1,200-unit batch only ties with a 600-unit batch when the fixed cost of sending a shipment reaches about $1,400. Below that, the free window wins; above it, paying storage beats paying freight.

That is the test worth running on your own operation: not “is a bigger shipment cheaper to send” — it always is, per unit — but “is the freight I save per unit bigger than the storage I take on per unit.” With a $0.556 cu ft box, doubling the batch from 60 days of stock to 120 days takes on $1.17 a unit of storage, so you would need to be saving more than $1.17 a unit of freight for it to be worth it.

Slow sellers: the case the free window cannot fix

Everything above assumes you can choose your batch size. Sometimes you cannot — a minimum order quantity, a factory that only ships full cartons, or a freight rate that only makes sense at volume. That is where this gets expensive, because a slow seller has to hold a big batch for a very long time.

Same box, same $120 per shipment, but now selling 2 units a day with a 600-unit minimum:

Taking the 600-unit minimum costs $11.50 a unit in storage. On a $29.99 product that is 38% of the selling price spent on warehouse time, against the $1.00 a unit it would cost to send 120 at a time instead. The 60-day rule still points at the right answer — 120 units is 60 days of sales at this rate — it is just that the minimum order quantity is what stands between you and it.

If a supplier will not break the minimum, the honest comparison is between the $11.50 of storage and the cost of getting out of the constraint: a higher unit price on a smaller order, a domestic supplier, or holding the stock yourself and sending it in as it sells. All three are usually cheaper than $11.50 a unit. That judgement is ours, not something the rate card says.

Three ways this gets misread

“Storage is free for two months, so I get two months free every time I restock.”

You get 60 days per unit, once, from the day it arrives. Restocking monthly does not extend the window on units already inside it, and a unit that arrived in January is billing in March whether or not a new shipment landed in February.

“A bigger shipment is always cheaper per unit.”

It is cheaper per unit on freight and more expensive per unit on storage, and the storage side accelerates. In the first example the freight saving from 600 to 900 units is $0.07 a unit and the storage cost is $0.50 a unit. “Cheaper per unit” only holds for the cost you are looking at.

“I will send extra before Q4 so I am not caught short.”

The rate card we read has no seasonal term anywhere in it — it is keyed to inventory age and nothing else. Stocking up early therefore costs exactly what its age costs, no more and no less, and the question stays the same one: will it sell inside 60 days of arriving? (Amazon FBA does charge more in Q4, but that is Amazon’s card.)

What to actually do

• Work out 60 days of sales for each SKU. That is your default batch size: 120 units at 2 a day, 600 at 10 a day, 1,500 at 25 a day.
• Price the batch before you send it, not after. The FBT Storage Fee Calculator prices any quantity at any holding period against the eight tiers.
• Put a number on your fixed shipping cost. The free window stops being the cheap answer only above roughly $1,400 a shipment in the example above; know which side of that you are on.
• Check the minimum order quantity against the storage it forces. A 600-unit minimum at 2 sales a day is $11.50 a unit of storage — worth paying a higher unit price to avoid.
• Watch inventory age, not just quantity. Two batches of the same size can cost very different amounts depending on when each arrived.
• Check the margin survives the batch you picked. Storage lands in per-unit cost, and the profit calculator is where you see whether the unit still clears it.

Where we stop short. The eight rates, the 60-day free window, the daily basis, the defective-unit rule and the age formula are TikTok’s, from the rate card and its calculation notes. The restock model is ours: the steady-sales assumption, the $120 shipment cost, the 12×10×8 in box, the 10-and-2-units-a-day rates and the 600-unit minimum are inputs we chose to make the arithmetic visible, not figures TikTok publishes or recommends. Three things we do not model: demand that is seasonal or lumpy (which makes some units sit longer than the batch average), stockouts and the sales they cost you (which push toward sending more, against everything above), and cash tied up in inventory (which pushes toward sending less). One thing we genuinely do not know: whether inbound transit time counts toward storage days — TikTok defines Storage Days as Outbound Time minus Inbound Time but the card we read does not say what sets Inbound Time, and for sea freight that gap could be weeks. Your own Seller Center invoices are the authority on what you were actually charged.

Frequently asked questions

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