3PL shipping markup: how it works and how to check yours
How 3PLs mark up carrier charges (percent, per-label fee or bundled), what your contract should say, and how to check the markup with a carrier cost column.
A shipping markup is what your 3PL adds on top of what the carrier charged for each label, either as a percentage of the carrier cost or as a flat fee per label. There is no standard rate: some 3PLs pass carrier costs through at cost, others add a margin, and the only number that matters for your invoice is the one in your contract. You can check it line by line whenever the invoice shows the carrier cost beside the billed amount.
How 3PLs bill shipping
When the warehouse buys labels on its own carrier accounts, it bills them on to you. How any margin is built in varies:
| Model | How it shows on the invoice | What to check |
|---|---|---|
| Pass-through at cost | Billed postage equals carrier cost | Billed ÷ cost = 1.00 |
| Cost plus a percentage | Billed postage is cost × (1 + markup) | The percentage matches the contract |
| Cost plus a per-label fee | A fixed amount added to every label | The fee matches, and it is not also charged as a percentage |
| Bundled into a per-order rate | No separate postage line | What the per-order price includes |
| Your own carrier account | Carrier bills you directly | Any label or integration fee from the 3PL |
Each of these exists in practice. Many 3PLs pass through actual carrier costs without markup (Extensiv). 3PL billing software lets a warehouse set a label fee as a flat amount per label, a percentage of the label cost, or both (ShipHero). Some 3PLs include postage in a flat per-order rate, and with your own carrier account your contract rates apply rather than the warehouse's (Fulfyld).
Discounted carrier accounts
One US 3PL's 2025 guide says 3PLs use combined client volume to negotiate deeper carrier discounts and often provide 10% to 30% off standard rates (Red Stag Fulfillment). The same guide lists the shipping line as anywhere from a 0% to 12% markup or discount over or under negotiated carrier rates.
So a markup on a discounted rate can still be cheaper than shipping on your own account. That is a fair trade, as long as the markup is what you agreed. The question for an audit is not "is there a markup?" but "is the markup the one in the contract?"
Percent or per-label fee: how they compare
A percentage scales with the label price. A flat fee does not, so it weighs more on cheap labels. To compare the two, convert the fee to a percentage of the carrier cost:
| Carrier cost | $1.00 per-label fee as a percent | 8% markup in dollars |
|---|---|---|
| $8.00 | $1.00 ÷ $8.00 = 12.5% | $8.00 × 0.08 = $0.64 |
| $12.00 | $1.00 ÷ $12.00 = 8.3% | $12.00 × 0.08 = $0.96 |
| $20.00 | $1.00 ÷ $20.00 = 5.0% | $20.00 × 0.08 = $1.60 |
If most of your labels are light ground parcels, a flat fee can cost more than it looks.
What your contract should say
Vague wording such as "shipping billed at competitive rates" makes markup impossible to check. Clear contracts cover:
- The markup itself, as a percentage or a dollar amount per label.
- What "carrier cost" means: the net amount the 3PL actually pays the carrier, not a published list rate.
- Whether surcharges are marked up. One 3PL's guide says most 3PLs pass the carrier's fuel surcharge straight through, and suggests asking whether they add a margin on top (Red Stag Fulfillment). Ask the same about residential and delivery area surcharges, and about carrier adjustments billed after the fact.
- Visibility: the carrier cost shown per label on the invoice detail. In some billing systems, showing actual label cost to clients is a setting the 3PL turns on (ShipHero).
If you are negotiating or renewing, have a lawyer review the wording.
Worked example: 8% vs 12%
Juniper & Pine is a made-up brand, and Ridgeline Fulfillment is a made-up warehouse, from our public sample audit. Their contract says: "Postage and carrier charges are billed at carrier cost plus 8%."
Take one UPS Ground label with a carrier cost of $9.34:
- Allowed at 8%: $9.34 × 1.08 = $10.0872, which rounds to $10.09.
- Billed: $10.46.
- Actual markup: ($10.46 − $9.34) ÷ $9.34 = $1.12 ÷ $9.34 = 0.1199, or 12%.
- Overcharge on this label: $10.46 − $10.09 = $0.37.
That looks small. But the same 4-point gap applied to all 1,007 labels over three months, which carried about $10,440 of carrier charges. In total it came to $417.58, the largest single finding in the sample audit. As a check, 4% of $10,440 is $417.60, which matches once you allow for per-label rounding.
At a round figure: if a brand pays $10,000 a month in carrier charges, 8% is $800 and 12% is $1,200. The $400 monthly difference is 12 × $400 = $4,800 a year.
How to check your markup
You need the invoice detail with a carrier cost column. Column names vary ("Carrier Cost", "Base Cost", "Label Cost"). If there is none, ask for it, because without it you cannot test the markup at all.
- Put the postage lines in a spreadsheet with the billed amount and the carrier cost side by side.
- Add a markup column: billed ÷ carrier cost − 1.
- Sort by that column. Every line should sit at the contract markup. Allow a cent either way for rounding.
- Work out the allowed amount for each line: carrier cost × (1 + contract markup), rounded to the cent.
- Sum the excess: billed minus allowed, for every line above the allowed amount.
- Check surcharge lines separately. A residential surcharge on a business address is its own question. See the residential surcharge and fuel surcharge pages.
Or test a few lines here:
If every line shows the same wrong percentage, the cause is likely a single setting in the warehouse's billing system, which makes the fix simple and the credit easy to calculate. Include a handful of example lines and the total in your request. Our audit method covers the other checks, and common billing errors shows how markup compares with the rest.
Check your shipping charges
3PL Checker tests the markup on every label in your invoices against your contract, along with surcharges and every other charge. A person reviews each finding, and you get the evidence and a credit request ready to send. The first audit is free.
Questions
What is the average shipping markup?
There is no reliable published average. One US 3PL's 2025 pricing guide lists a range of 0% to 12% as a markup or discount relative to negotiated carrier rates, and many 3PLs pass carrier costs through without markup. The number that counts is the one in your contract.
What does shipping markup mean?
It is the difference between what the 3PL pays the carrier for a label and what it bills you. It can be a percentage of the carrier cost, a flat fee per label, or built into a per-order price.
How do you calculate markup on shipping cost?
Markup % = (billed amount − carrier cost) ÷ carrier cost × 100. A label billed at
0.46 with a $9.34 carrier cost has a markup of .12 ÷ $9.34 = 12%.
How do 3PL shipping rates work?
When the 3PL buys labels on its own carrier accounts at negotiated rates, it bills you at cost, at cost plus a markup, or inside a flat per-order rate. Some let you ship on your own carrier account instead.