· Regulation · 38 sources · opinion
Parcel rules worldwide cap phone cells at 20 Wh. Apple says the 18 Pro Max's is over that
From USPS to Australia Post, carriers take phone battery cells up to 20 Wh, and Apple says the iPhone 18 Pro Max's is bigger. Its Prepare to Ship setting drains the phone below the line, but Apple names no rule it relies on, and the air-safety regulators are about to debate limits like this one.
The short answer
Can you post an iPhone 18 Pro Max? Nobody responsible for the answer has given one publicly, as far as I can find. Almost every parcel and postal network whose terms I read takes phones on one condition: each lithium-ion cell inside is rated at 20 watt-hours or less. Apple says this phone’s single cell is over 20 Wh.
- The cell: reported figures put it at about 21.06 Wh in the physical-SIM model sold in the UK, Europe and Australia, and 21.75 Wh in the eSIM-only model sold in the United States.
- Apple’s answer: a setting called Prepare to Ship drains the battery below 20 Wh and caps its charge. Apple says the step is “needed only to meet shipping requirements” but does not name the requirements, the rule that lets a charge cap count, or any approval.
- The carriers: none whose terms I read says whether a prepared phone meets them.
- The regulators: the only one that has ruled on the mechanism, in the United States, split its answer on a detail Apple’s documents leave out. From 26 to 30 October a working group of the international air-safety body’s dangerous goods panel is due to discuss a paper asking whether limits of this kind should count at all.
- Status: this is the position on 22 October 2026. If a carrier, a regulator or Apple answers, or the ICAO meeting publishes an outcome, I will update this piece with a dated note.
Where this comes from
This is a reading of published documents, nothing tested. I read Apple’s own support pages for the phone in seven regional versions, and the UN rule the 20 Wh figure comes from, with the national codes that copy it. I read the published terms of more than thirty postal services and couriers across North America, Europe, Australia, New Zealand and Asia, two written interpretations from a United States regulator, and a working paper filed with the International Civil Aviation Organization (ICAO) on 13 October. I read every document on 22 October 2026, whatever date it carries itself. Where a carrier’s page did not load, or the only copy I could find was old, I say so or leave it out. The sources list below covers the main documents; for the German, French, Dutch, Belgian, Spanish, Swiss, Irish, Swedish and Japanese carriers I hold dated copies of each page quoted. I have not contacted Apple, any carrier or any regulator for this piece, so nothing below is a response from any of them.
What I found
The cell
iFixit’s teardown gives the eSIM-only 18 Pro Max’s battery as “21.751 Wh (5567 mAh)” and notes that “Physical SIM models have smaller batteries”. Apple’s own model identification page says there is no SIM tray in the United States, Canada, Japan and several Gulf states, and a tray everywhere else. The physical-SIM model, A3717, is the one listed on Apple’s UK specifications page, and the EU’s EPREL energy database gives its rated capacity as 5,391 mAh. Apple publishes no watt-hour figure for either. The Verge reports “21.06Wh for European models with a physical SIM slot”, which is what 5,391 mAh comes to at the same nominal voltage as the eSIM cell.
Either way it is one cell over 20 Wh. Apple says so itself: the phone gains battery life “in part due to increasing the battery capacity to over 20 watt-hours (Wh)”.
What Apple says
Apple’s support document Prepare your iPhone 18 Pro Max to ship (UK version dated 30 September 2026) is the whole of Apple’s public explanation. The key passages:
- “Devices with a single-cell battery over 20 Wh have additional shipping requirements in most countries and regions.”
- A new phone “uses an innovative battery-firmware solution that limits battery capacity to below 20 Wh from the time it’s manufactured through its transport from the factory. When you activate your iPhone, the limit is removed”.
- After that, Prepare to Ship “discharges your battery to below 20 Wh and sets a charge limit so your iPhone stays below this limit while shipping”. For a repair, trade-in or return, “the battery charge limit will be capped at 80 per cent for 14 days”.
- It is turned on in Settings, under General, Transfer or Reset iPhone. To undo it later, Apple says you can change the charge limit in Settings, under Battery, Charging.
- “The battery in iPhone 18 Pro Max is safe, including for shipping and air travel. This process is needed only to meet shipping requirements and isn’t required while travelling or for any other iPhone model.”
- If it fails: “Don’t ship your device, because you’ll likely need specific packaging.”
The page names no regulation, standard, regulator, approval, carrier or country, and nor do the American, Canadian, Australian, German, French or Japanese versions I compared. In it, Apple uses the word firmware for the factory limit only. It does not say which part of the phone enforces the Prepare to Ship limit: the battery’s own management chip, or iOS.
A second Apple page, Shipping your iPhone 18 Pro Max to Apple, covers phones going back in an Apple shipping kit and gives a different instruction: “Let your iPhone battery discharge to 25 percent or less, then turn off your iPhone.” It also sets conditions. A cracked phone can go “only if the crack doesn’t expose the device’s interior, the device isn’t bent or dented”, and a phone that fails the criteria should not be shipped at all: “contact Apple Support, or visit an Apple Store or an Apple Authorized Service Provider.”
Where the 20 Wh line comes from
The figure is not a carrier’s own choice. It is special provision 188 of the UN’s dangerous goods rules, copied word for word into the European road agreement, ADR, which governs road transport across Europe, including the UK: a lithium-ion cell is exempt from the rest of the rules if “the watt-hour rating is not more than 20 Wh” (ADR 2025, Volume I, pp. 591-592). The same 20 Wh test appears in the Australian Dangerous Goods Code, in 49 CFR 173.185(c) in the United States, in Canada’s Transportation of Dangerous Goods Regulations, in the air rules, and in the Universal Postal Union’s rules for international mail: “for a lithium ion cell, the Watt-hour rating shall not be more than 20 Wh.”
Two details in that wording matter here. First, the 100 Wh figure you often see beside it is for multi-cell batteries, and the rules say plainly that “a single cell battery … is considered a ‘cell’” and is judged against 20 Wh. Second, the rules define the rating rather than leaving it to the label. The current UN Manual of Tests and Criteria defines it as “the energy value of a cell or battery determined under specified conditions and declared by the manufacturer”. The manual’s definitions say nothing about firmware or software, and that phrase, “specified conditions … declared by the manufacturer”, is where the whole question sits.
Above 20 Wh a phone does not become forbidden. It becomes fully regulated dangerous goods, UN 3481, with the classification, packaging, marking and paperwork that brings, and most consumer post does not accept dangerous goods at all.
Can you post one? What the carriers’ terms say
None of the carriers’ published terms I read mentions Prepare to Ship, firmware limits or the 18 Pro Max. What they do say about a phone with a cell over 20 Wh:
- Royal Mail and Parcelforce (UK). “Watt-hour rating must not exceed 20Wh per cell or 100Wh per battery” for batteries in devices. Business accounts: “all variants of Royal Mail 24 and Royal Mail 48 are excluded” for these items regardless.
- DPD (UK). Prohibits “non-excepted batteries”. The excepted ones are those meeting special provision 188.
- Evri (UK). Batteries can go “if they are included with the equipment they power”; prohibits “Batteries that are classified as dangerous goods”. No Wh figure.
- InPost (UK). “Anything that contains a battery … is a Prohibited Item”. Every phone, not just this one.
- USPS (United States). “Cells must not exceed a 20 Wh rating”, by air or surface. No route above it.
- FedEx Ground (United States). Cells over 20 Wh and up to 60 Wh can go by road in a box marked “LITHIUM BATTERIES - FORBIDDEN ABOARD AIRCRAFT AND VESSEL”. Not to or from Alaska or Hawaii.
- UPS, FedEx Express, DHL Express (worldwide). Over 20 Wh is fully regulated: a dangerous goods contract or approved account, and a shipper’s declaration.
- Canada Post (Canada). Mails lithium batteries only within the 20 Wh exemption; other dangerous goods are “non-mailable”.
- DHL Paket / Deutsche Post (Germany). 20 Wh per cell; fully regulated goods “nicht möglich” (not possible).
- Chronopost, La Poste, Colissimo (France). 20 Wh per cell; Chronopost marks the rest “INTERDIT” (forbidden).
- PostNL, bpost, Correos, Swiss Post (Netherlands, Belgium, Spain, Switzerland). 20 Wh per cell; nothing above it accepted.
- Hermes, An Post, PostNord (Germany, Ireland, Sweden). No dangerous goods or no batteries at all.
- Australia Post (Australia). “20 watt-hour per cell or 100 watt-hour per battery”. Its dangerous goods guide routes cells over 20 Wh to StarTrack’s dangerous goods service only, by air and by road.
- NZ Post (New Zealand). “Each Lithium-ion cell - maximum 20 Watt-hours.” A dangerous goods parcel carries a NZ$130 plus GST surcharge.
- Japan Post, Yamato (Japan). 20 Wh per cell; above it, ground only and up to a week slower.
- SingPost (Singapore). “Cell rating: ≤ 20Wh”; anything else “cannot be accepted even as sea mail.”
- Hongkong Post (Hong Kong). “Equipment containing non-removable lithium battery must NOT be posted.” Every phone.
Every set of terms that gives a figure sets it on the cell’s rating. None of them sets it on how full the battery is. Wherever they address damaged batteries, they refuse them outright: Royal Mail’s wording is “Damaged or recalled batteries or cells are not allowed”. That applies to every phone, whatever its model, and is a separate point from the 20 Wh one.
The one regulator that has ruled
In June 2025, more than a year before the phone launched, the United States Pipeline and Hazardous Materials Safety Administration (PHMSA) answered a compliance consultancy’s questions about exactly this mechanism. Its interpretation 25-0021 does not mention Apple. It gives two different answers depending on where the limit lives:
- If “the cell or battery firmware limits the nominal energy” to 20 Wh, the answer is “Yes”: the cell “can be considered a smaller lithium ion cell or battery for transportation”, because “Firmware that controls the voltage and ultimately the nominal energy is within the design and specified conditions of the lithium ion cell or battery manufacturer.”
- If “the equipment’s software limits the nominal energy”, the answer is “No”, because that software “is not inherent to the battery itself”, and the manufacturer’s declared rating for the cell has to be used instead.
- Firmware the user can switch back is allowed, but the battery “must be marked with the Wh rating allowed by the currently operative firmware before transportation in commerce”.
An earlier PHMSA letter, 22-0113 from January 2023, reached the same “Yes” for a battery capped at 100 Wh by its firmware. PHMSA’s view is the most favourable reading for Apple that I found, and Apple’s phrase “battery-firmware solution” fits the “Yes” side of it. But Apple uses that phrase for the factory limit only. Prepare to Ship is reached through iOS Settings, and Apple does not say whether the limit it sets is enforced by the battery’s own firmware or by the phone’s software, which is the distinction PHMSA’s answer turns on. iFixit reports the eSIM cell at 21.751 Wh, and if that is what the cell is marked, it is the full figure rather than a firmware-limited one. iFixit’s wording does not say outright that the Pro Max figure is the label reading, so that last step is my inference rather than a documented fact.
I found no equivalent ruling from any regulator in the UK, Europe, Australia, Canada or Asia. PHMSA’s letters bind American transport only.
The question going to the air regulators
A working paper dated 13 October and filed with ICAO’s Dangerous Goods Panel is titled “Adjustable firmware in a battery - regulatory interpretation” (DGP-WG/26-WP/28), for the panel’s working group meeting in Centurion, South Africa, from 26 to 30 October. It is presented by an individual panel participant and carries, as an appendix, a draft discussion paper from IATA, the airlines’ trade association. It does not name Apple or any product. It says airlines and freight forwarders were approached in May 2026 and asked whether they would carry batteries limited by firmware under the PHMSA letter. It then asks the working group to put this question to the panel:
“Is it appropriate for batteries that physically exceed established lithium battery energy thresholds to gain access to reduced regulatory requirements through adjustable firmware-imposed operating limitations, when those thresholds were originally established as the trigger for additional safety-based controls in air transport?”
It notes that such limits are “not readily visible or independently verifiable by operators, regulators or other supply chain participants”, flags “return logistics involving defective products” as a particular difficulty, and records that while “an interpretation has been provided by one regulatory agency”, other authorities IATA approached “have not received a request for an interpretation in their jurisdictions”. It is also fair about the other side: the IATA appendix says there “is comfort with responsible large-scale global product manufacturers”, and that the concern “is less about a specific 20 Wh versus 22 Wh debate and more about the precedent”.
The line may move, but has not
The 20 Wh figure is under pressure for reasons that have nothing to do with Apple. A paper from China’s delegation to the UN dangerous goods sub-committee in November 2025 proposed raising the cell limit to 40 Wh, noting that “in 2021, only 6.25 per cent of smartphone battery had a watt-hour rating greater than or equal to 20 Wh, while in 2024, 50 per cent”. In July 2026 the sub-committee concluded that “further technical work and more comprehensive data would be required to support any revision”. At the same session it adopted a separate draft, proposed by the UK with two industry bodies, that would set a 50 Wh limit for single-cell batteries in a future edition of the UN rules (addendum). That is a draft amendment to the UN model rules only. It is not in the 2027 edition of ADR, and no date has been set for it to reach road, postal or air rules.
What the coverage said
The launch coverage I read, from MacRumors, 9to5Mac, The Verge, AppleInsider, Daring Fireball, TidBITS and others, mostly restated Apple’s support page. Two German outlets raised the obvious doubt: heise wrote that “it remains to be seen whether all logistics providers will agree to this”, and TECHBOOK that “Whether the solution actually meets all transport requirements in practice remains unclear.” None of the articles I read quoted a carrier, an airline or a regulator, and only one small blog mentioned the PHMSA letter. Two network operators have published instructions: Verizon tells owners to use Prepare to Ship and sends returns out with “lithium battery warning stickers”, and AT&T describes it as being “to comply with international transport regulations”.
What it means for you
If you repair, insure, buy back or refurbish phones, the 18 Pro Max is the first mainstream phone where the posting question is not settled by the terms you already work to. In practice:
- Ask before anyone posts one. If customers send you phones, or you send them out, tell them in advance how you want an 18 Pro Max handled. Apple’s own advice is to contact the receiving company before using Prepare to Ship, because “Sometimes, companies have steps for you to complete”. For a trade-in or return Apple also says “you must remove Activation Lock”, which matters for salvaged parts too.
- Expect the phones that can’t be prepared. Prepare to Ship is run on the phone itself, and Apple’s advice for a phone whose screen “isn’t usable” is to contact Apple or the receiving company before shipping it. A phone that won’t power on can’t run it at all. Phones like that are routine in repair, and for them Apple’s own answer is “specific packaging”, which, as I read the carriers’ terms, means a dangerous goods service: a UPS, FedEx or DHL dangerous goods account, StarTrack in Australia, or a specialist courier.
- Hand-over is the simple route. Apple says the process “isn’t required while travelling”, so on Apple’s account a phone carried in person to a shop or a collection point needs no preparation. Some businesses ask for it anyway: Verizon tells owners to set it “before returning it to a retail location or shipping it back”.
- Damaged batteries are a separate matter. A swollen, punctured or recalled battery is refused by every carrier whose terms I read that addresses it, whatever the phone.
- In the United States there is a lawful road route. 49 CFR 173.185(c)(1)(iv) lets cells up to 60 Wh travel “by highway or rail only” in a box marked as forbidden aboard aircraft and vessels. FedEx Ground offers this, but not to or from Alaska or Hawaii. I found no equivalent in the UK, European or Australian postal networks.
- If you are sending your own phone. Apple’s steps are to contact the company you are sending it to first, then turn on Prepare to Ship in Settings and, for a trade-in or return, remove Activation Lock. A new phone that has never been activated needs none of this: Apple says its battery “is temporarily limited to under 20 Wh already”. The iPhone Duo, on sale a month later, is a different design with its own repair manual and its own screen rules.
Three questions would settle most of this, and they are worth putting to the people who can answer them:
- To Royal Mail, DPD, Australia Post, USPS and the other carriers: does a prepared 18 Pro Max meet your 20 Wh per cell condition, given that Apple says its cell is over 20 Wh?
- To the national dangerous goods authorities, in the UK the Department for Transport’s dangerous goods team: does a charge limit set in a phone’s software, or in its battery’s firmware, change a cell’s watt-hour rating under special provision 188?
- To Apple: which regulations and approvals is Prepare to Ship based on, is its limit enforced by the battery’s firmware or by iOS, and what watt-hour rating is marked on the cell?
OpinionA judgement on the facts above, not a finding. It rests only on what is quoted on this page.
My view
In my view, the couriers’ own terms don’t allow this. Every set of terms I read that gives a figure sets it on the cell’s watt-hour rating, not on how full the battery is, and Apple itself says the 18 Pro Max’s battery is over 20 Wh. Prepare to Ship is, as far as an owner can see, a software toggle: it is switched on in Settings, its limit is changed in Settings, and Apple uses the word firmware only for the limit set at the factory. The one regulator that has ruled on limits like this said a limit in the device’s software does not count.
Apple says the battery is safe and that the step is needed only to meet shipping requirements, and that stated reason may well be right: a drained, capped phone may be no more of a risk than a smaller one. The American regulator accepted that a limit built into the battery itself can change its rating, and the air-safety regulators are only now debating the wider question. But no carrier has said a prepared 18 Pro Max meets its terms, and Apple hasn’t said which rules it relies on. Until one of them does, my read is that this phone is, for now, unshippable by ordinary post or parcel unless it goes as declared dangerous goods. The one exception is the United States, where road rules allow cells up to 60 Wh in a marked package.
Opinion, based on the evidence set out above.