What to Include on an Invoice: A Complete Checklist

Essential Contact Details and Identification

Every invoice must start with clear identification. You should prominently display the word Invoice so the recipient knows exactly what the document is for. Below this, you must include your full business name and address. If you are a sole trader, you should use your own name, though you can also include a business name if you have one. If you are a limited company, the invoice must show the full registered company name as it appears on the Certificate of Incorporation and the registered office address.

The customer details are equally important. Include the name and address of the individual or business you are billing. This ensures the document is legally attributed to the correct party for their own accounting records. While not strictly required by law for all small transactions, including a phone number or email address for both parties can speed up communication if there are questions about the bill. Using a tool like Invoice Maker Simple allows you to enter these details into a step by step form, ensuring no contact information is missed.

• Full business name and registered address
• Customer name and billing address
• The word Invoice clearly displayed
• A unique and sequential invoice number
• The date the invoice was issued

Detailed Itemisation of Goods and Services

A common cause of payment delays is a vague description of work. You must provide a clear, line by line breakdown of what you are charging for. For a service provider, this might mean listing specific tasks completed or hours worked. For a retailer, this involves listing the specific items sold. Each line item should include a quantity, a unit price, and the total amount for that line. This level of detail helps the customer understand exactly what they are paying for and reduces the likelihood of them challenging the bill.

When using Invoice Maker Simple, you can add as many line items as necessary. For example, a graphic designer might list Logo Design as one item and Brand Guidelines as another. By separating these, you provide a transparent view of your pricing structure. If you have agreed on a fixed project fee rather than an hourly rate, you should still describe the scope of work covered by that fee. This protects both parties by defining what was delivered for the price stated.

• Specific description for each line item
• Quantity or hours for each service
• Unit price or hourly rate
• The date the work was completed
• Individual totals for each row

Financial Calculations and Totals

The bottom section of your invoice is where the final math happens. You must clearly state the subtotal, which is the sum of all line items before any extras like tax or shipping are added. If you have offered a discount, this should be clearly subtracted. Discounts can be a fixed amount, such as ten pounds off, or a percentage of the total. Showing the discount as a separate line helps the client feel they are getting value and makes the final calculation easy to follow.

If you are charging for delivery, this should be listed as a separate shipping cost rather than being hidden inside the item prices. Once all items, discounts, and shipping are accounted for, you calculate the grand total. This is the most important number on the page and should be formatted in a bold or larger font so it stands out. For businesses working internationally, Invoice Maker Simple supports 48 different currencies, ensuring that the total is expressed in the correct monetary unit for your client.

• Clear subtotal before taxes or fees
• Specific discount amounts or percentages
• Shipping and handling costs
• The final grand total due
• Correct currency symbol and code

Related: How to Create an Invoice: A Step by Step Guide for Beginners

Specific Requirements for VAT Registered Businesses

If your business is registered for VAT in the UK, your invoices must meet stricter legal requirements set by HMRC. You must include your nine digit VAT registration number. Failure to include this can prevent your business customers from reclaiming the VAT they pay you, which will likely lead to complaints and payment delays. The invoice must also show the tax rate for each item, whether it is standard rate, reduced rate, or zero rated. Note that Invoice Maker Simple applies one rate to every item, so it suits invoices where all items share the same rate. Most goods and services are standard rate, but you should verify this on the GOV.UK website.

For each item, a full UK VAT invoice shows the description, quantity, price excluding VAT and the VAT rate, plus the total VAT for the whole invoice. At the bottom of the invoice, you should provide a summary table that shows the total net amount, the total VAT amount, and the gross total. This level of detail is mandatory for what is known as a full VAT invoice. If you sell an item that is exempt from VAT, you must clearly state that no VAT has been charged for that specific line.

• Your nine digit VAT registration number
• The VAT rate applied to each item
• The total amount of VAT payable
• Net price excluding VAT for each line
• Gross total including all taxes

Additional Details for Tradespeople

Tradespeople such as plumbers, electricians, and builders often have unique invoicing needs. Because your work often involves a mix of labour and materials, it is best practice to separate these on your invoice. For example, instead of writing Kitchen Repair, you should list the specific parts used, such as pipes or valves, and then a separate line for the labour hours. This transparency builds trust with homeowners and provides necessary detail for commercial clients who may need to track asset costs.

• Separate lines for materials and labour
• CIS deduction notes if applicable
• Reference to the original quote number
• Clear description of the work location
• Breakdown of any third party hire costs

Payment Terms and Instructions

Even a perfectly formatted invoice will not get you paid if the customer does not know how to send the money. Include the details your client needs to pay you, such as account name, sort code and account number for UK bank transfers. If you are taking payments through other methods, provide the necessary links or IDs. It is also wise to specify your payment terms, such as Payment due within 30 days. Without a specific due date, a customer may assume they have much longer to pay, which can hurt your business cash flow.

In the UK, for business-to-business work with no agreed payment date, payment is generally treated as late after 30 days. For business-to-business debts you may also be able to charge interest under the Late Payment of Commercial Debts (Interest) Act. Mentioning your payment terms clearly helps set expectations from the start. You might also include a short thank you note or a reference to your website. Invoice Maker Simple allows you to upload a logo and choose colours, which helps your payment instructions look professional and aligned with your brand.

• Bank account name and sort code
• Account number and IBAN for international
• Payment due date or net terms
• Late payment interest policy note
• Contact info for billing queries

Common Invoicing Mistakes to Avoid

One of the biggest mistakes is sending an invoice with incorrect tax calculations. If you are not VAT registered, you must not charge VAT. If you are registered, failing to show the breakdown correctly can lead to legal issues. Another frequent error is using a non-sequential invoice number or duplicating a number from a previous job. This creates confusion during tax audits and makes it difficult to prove your income. Using a dedicated invoice maker helps avoid these structural errors by providing a pre-built framework.

Vague descriptions are another common pitfall. Terms like Consultancy or Services Rendered are often rejected by larger companies because they do not provide enough information for an audit trail. Be as specific as possible. Instead of Landscaping, use Mowing, weeding, and hedge trimming at 123 Maple St. This leaves no room for doubt about what was done. Also, ensure your contact details are up to date. If you move house or change your business phone number, update your invoice template immediately so clients do not send correspondence to the wrong place.

• Charging VAT when not registered
• Using duplicate invoice numbers
• Providing overly vague descriptions
• Forgetting to include bank details
• Waiting weeks to send the bill