What is a purchase order?

A purchase order is a formal document sent by you, the buyer, to a supplier. It clearly sets out what you want to buy, how much you need, and the price you have agreed to pay.

With supply chains under pressure and costs needing close control, using purchase orders shows your business is organised and reliable. It moves your buying process away from informal emails or verbal agreements into a clear system that protects both sides. This guide explains how purchase orders work, how they differ from invoices, and how they can support your business credit profile.

How does a purchase order work in the UK?

A purchase order is usually the first official step in a business transaction. It acts as an offer to buy goods or services on agreed terms. For the supplier, receiving a purchase order confirms the order is approved and that payment has been planned. For you as the buyer, it creates a clear record to make sure you receive exactly what you ordered at the agreed price.

When a supplier accepts a purchase order, it often forms a legally binding contract between both businesses. This gives protection if there is a disagreement about product quality, delivery times, or pricing. Under UK contract law, the purchase order sets out what the buyer must pay and what the supplier must deliver.

What is a purchase order number and why do you need one?

Every professional purchase order must include a unique identifier known as a purchase order number. This is a reference code that allows both the buyer and the seller to track the transaction through every stage of its lifecycle.

This number is important for your internal records and audits. When goods arrive, your team can check the delivery against the purchase order number to confirm it matches what was ordered. When the invoice arrives, the purchase order number makes it easier for your finance team to approve payment, as they can quickly match it to the original order in your system.

What should be included in a professional purchase order?

To be clear and legally sound, a purchase order must include specific key details. Most modern accounting software will generate these automatically, but it is important to ensure the following information is always included:

• Buyer and supplier details: Full company names, registered addresses, and contact information.

• Detailed descriptions: A clear list of the items or services requested, including SKU numbers or specific part codes.

• Quantities and prices: The exact number of units required and the agreed unit price, along with the total order value.

• Delivery information: The expected delivery date and the specific address where goods should be sent.

• Payment terms: The agreed timeframe for payment, such as "Net 30 days," which dictates when the supplier can expect their funds.

What is the difference between a purchase order and an invoice?

It is common for new business owners to confuse purchase orders with invoices, as they often contain similar information. However, they serve opposite purposes in the transaction cycle. The purchase order is a document of intent. The invoice, on the other hand, is the request for payment. An invoice should always reference the original PO number. This allows your finance team to perform "three way matching," where they compare the purchase order, the delivery note, and the invoice to ensure everything is correct before any money leaves your bank account.

This table breaks down the key differences:

Which types of purchase orders should your business use?

Depending on your business needs, you may use different types of purchase orders to manage your supply chain:

• Standard purchase orders

  Standard purchase orders are used for one off transactions where the items, prices, and delivery dates are all known upfront. This is the most common type for buying office equipment or specific project materials.

• Blanket purchase orders

  Blanket purchase orders are used for recurring needs over a set period. For example, if you know you will need a certain amount of raw materials every month for a year, a blanket PO allows you to negotiate a bulk discount while spreading the deliveries out.

• Planned purchase orders

  Similar to blanket orders, planned purchase orders are used when you know exactly what you need but the delivery dates are not yet confirmed. This helps suppliers plan their own production schedules while giving you the flexibility to call off stock as needed.

What is purchase order finance and how does it help?

Sometimes, winning a large contract can be a double edged sword. If a client sends you a significant purchase order but you don’t have the cash on hand to buy the raw materials or stock needed to fulfil it, your growth could stall. This is where purchase order finance can help.

Purchase order finance is a form of funding where a lender advances you the money needed to pay your suppliers based on a confirmed purchase order from a creditworthy customer. Instead of waiting for the customer to pay you weeks or months later, the lender covers the upfront costs. This allows you to take on larger projects that would otherwise be out of reach due to cash flow limitations. It is an excellent way to scale your business without taking on traditional long term debt.

How do payments and purchase orders affect your business credit?

Using a structured purchase order system does more than keep your records organised, it can also improve your business credit profile. Using purchase orders shows that your spending is planned and approved which helps prevent unplanned purchases that can lead to cash flow issues. Businesses that manage orders properly are less likely to miss payments, which is one of the most important factors in maintaining a strong credit score.

How to use Capitalise to better manage your purchases

At Capitalise, we help UK small businesses stay in control of their finances and access the funding they need to grow. Whether you are issuing purchase orders or receiving them, we support you at every stage. You can use our credit monitoring tools to understand how your payment history affects your business credit score and see what lenders see, helping you build a stronger profile over time. If you receive a large purchase order but do not have the cash flow to fulfil it, we can help you find specialist purchase order finance, allowing you to use the value of the order to pay suppliers and complete the work. You can also compare business loans and revolving credit facilities from over 100 UK lenders, giving you the flexibility to take on larger orders with confidence while keeping your cash flow stable.