Order backlog formula: how long until your shop catches up?

A promotion goes well, the packing queue grows and your dashboard still shows healthy sales. By the next morning, the queue is longer even though you worked late. This can happen without a slow packer: incoming work may simply exceed completed work. The useful question is how much spare capacity remains after today’s new orders. That spare capacity, rather than your total daily output, determines how quickly you can recover an existing dispatch backlog.

This guide is for a UK online seller shipping stocked goods. Every volume below is an illustrative input, not a report of an AirPost customer’s performance. Replace the inputs with your own queue and working-day calendar. For a general provider comparison, see fulfilment for fewer than 100 orders a month. Here the task is narrower: regain control of overdue work while the shop remains open. AirPost’s seller page explains the separate option of arranging suitable stock and dispatch work with a sender.

Which orders belong in your dispatch backlog? #

Choose one counting boundary. For a ready-to-pack queue, include paid or otherwise approved orders with available goods, a usable address and a confirmed shipping instruction. Keep pre-orders awaiting their planned release outside that queue. Keep payment reviews, missing stock and unresolved customer changes in a blocked list. Otherwise you may promise that extra packing hands will clear work that nobody is authorised or physically able to release. Write down the boundary beside the daily number so every person counts the same thing.

Maintain a separate view of all unfulfilled customer commitments. A blocked order still matters to its buyer even if it is excluded from the ready-work calculation. Give it a reason, an owner and a next decision time. If stock arrives and the order becomes executable, move it into the ready queue as incoming work on that day. This avoids counting it twice and explains why tomorrow’s ready backlog might jump despite steady sales. Never remove an order from the customer-commitment view merely to make the packing chart look better.

Why does backlog divided by output give the wrong recovery date? #

Dividing waiting orders by daily output is useful only when no new work enters that queue. If the shop keeps accepting orders, calculate spare daily capacity first: completed orders minus new ready orders. With stable positive spare capacity, recovery days equal opening backlog divided by that spare capacity, rounded up to an operating day. If the difference is zero, you hold the backlog level. If it is negative, the backlog grows. None of those formulas can predict a missing delivery of stock or an unexpected change in the order mix.

Use consistent units. One order containing several difficult products is not equal to one straightforward single-item order in labour terms. When that variation matters, convert the queue into measured work minutes by order type. Compare required minutes with minutes genuinely available for that work. Deduct the other jobs you still have to do: replenishment, dispatch administration, collection or drop-off and returns. Keep order counts for customer communication, but use the workload calculation to decide whether another shift solves the problem.

Which waiting orders should you pack first? #

Sort ready orders by the commitment at risk, then by age within that group. Identify purchases with a communicated essential date and orders whose promised window is already ending. Do not let a new easy order repeatedly jump ahead of an older difficult one just because it improves the completed count. If batching similar products helps, batch within a group that still protects those commitments. An urgent blocked order needs a stock or customer-service decision rather than a place in the packing line.

Set one release list for the shift and one person responsible for changing it. If a buyer cancels or changes an address, that person stops the physical order and replaces the instruction before packing resumes. Mark the change on the working record, rather than relying on a message somebody might read later. Keep cancelled labels away from active parcels. During recovery, repeated reprints and hurried edits are exactly where a faster production rate can turn into incorrect deliveries and more customer contacts.

What do UK delivery rules change about a recovery plan? #

The Consumer Rights Act 2015, section 28, gives specific consequences for missed delivery. Where delivery at the agreed time was essential, or the buyer told you before contracting that it was essential, the buyer may end the contract without first allowing an extra delivery period. In other cases the buyer can specify an appropriate additional period and end the contract if that is missed. A recovery queue therefore needs the original commitment, not just the purchase timestamp.

Section 28 also requires reimbursement without undue delay after that termination. Its commercial-unit rule prevents treating part of a unit as an independently cancellable purchase where division would materially impair its value or character. Those are separate questions from whether you can physically split a parcel. GOV.UK’s online-selling guidance also says to deliver within 30 days unless otherwise agreed. That default is not permission to ignore a shorter agreed window. Read the buyer’s actual order terms before choosing a recovery action.

Regulation 13 of the Consumer Contracts Regulations requires the prescribed pre-contract information to be supplied clearly and comprehensibly. For new sales during the backlog, explain the current arrangement before purchase rather than burying it in a later tracking message. GOV.UK also requires electronic order acknowledgement as soon as possible. An acknowledgement confirms receipt of the order; it does not establish that a parcel has left your premises. These official sources were checked on 13 October 2026.

Can temporary outsourced packing remove the waiting work? #

Only if goods, order information and an available executor can be in the same place in time. Sending stock to a new person takes preparation and transport before any customer parcel can leave. If the immediate problem is one missed afternoon collection, changing stock location may arrive too late to help. Compare that transfer time with the spare capacity you could add locally. For a recurring shortage, a limited stock handover may be worth exploring after you have stabilised the urgent queue.

AirPost’s checked price constants on 13 October 2026 give €0.85 platform fee plus €2.25 recommended sender compensation for a suitable small parcel. Those two components total €3.10 per shipment. A hypothetical handover of 40 separate small shipments therefore represents €124.00 for those components. Carrier labels, materials and moving the stock are additional; the sender’s agreed fee can differ. This is a euro-denominated comparison from the constants, not a fixed pound quote for UK work.

Ask which specific orders the sender can accept, how stock is identified and how completion will be reported. Do not infer spare capacity from a profile or assume an automatic connection for your shop software. Check the confirmed handover path before releasing customer data or moving goods. If the sender processes new routine orders while you clear the older queue, keep ownership of each order explicit. One shared shop list must not cause both locations to pack the same purchase.

How do you know the recovery is real? #

At a fixed daily checkpoint, reconcile opening ready work, newly released work, completions, cancellations and remaining work. Explain each adjustment separately. Keep the cancellation count visible: a lower backlog caused by customers leaving is a different outcome from dispatching their purchases. Also record the age of the oldest unresolved commitment and how many promised windows were missed. A shrinking total with one very old order ignored at the bottom is still an operational problem.

For eligible Royal Mail Click & Drop business orders, the official manifest guide describes automatic manifesting starting at 6.30pm on working days, excluding bank holidays. Orders in Label generated or Despatched can become Manifested. A generated label left unmanifested can also be automatically manifested after 60 days. Therefore, reconcile the administrative list with actual collection or drop-off before using it as your completed-work count. A box still by the exit needs investigation even when its software status has advanced.

Royal Mail also says a manifest containing only tracked services does not display an OBA sales order number, because tracked services are billed when mail is first scanned into its network. That difference matters when checking records during recovery: a missing number does not by itself establish a missing parcel. These carrier rules were read on 13 October 2026. Keep a record of physical handover alongside the relevant carrier information, and restore sales promises only to demonstrated capacity.