How to Use Tags and Categories to Organise Your Accounting Data
Your chart of accounts is essential. It's the structure that HMRC and the Companies Act 2006 require — it sorts transactions into revenue, costs, assets, liabilities. But it only gives you one view of your finances. You can't see which marketing channel actually works, which location is profitable, how much you spent on that special project. This is where tags and categories come in. They let you use tags and categories to organise your accounting data in ways your chart of accounts alone cannot support.
Why Your Chart of Accounts Alone Isn't Enough
Your chart of accounts is the backbone of your bookkeeping. It's fixed and standardised — salaries go to one account, rent to another, revenue to a third. This structure is essential for producing the financial statements your accountant needs and HMRC expects. But it's also blunt. It tells you total revenue and total marketing spend. It doesn't tell you revenue by product line, or marketing spend by channel, or whether your London office is profitable. If you want that level of insight, you need something else.
For many small-business owners, the frustration hits around month three: you have the numbers, but not the story. You know you spent £4,000 on marketing. You don't know whether Google Ads or social media or email drove the return. You know rent was £2,500. You don't know whether that's competitive for your location. You're tracking the money, but not the decisions.
This is the job of categories and tags. They work alongside your chart of accounts, adding organizational layers that let you answer the questions a fixed account structure can't.
Tags and Categories: What's the Difference?
Three things are at play here, and they often get confused.
Chart of accounts is your statutory structure. Every transaction posts to at least one account. It determines whether revenue appears on your profit and loss or whether an asset appears on your balance sheet. Non-negotiable.
Categories (also called cost centres, departments, or classes) add a second dimension. They represent structural divisions within your business — London office versus Manchester, Sales versus Operations, Consulting versus Products. A single transaction belongs to one category. Categories answer: Which part of the business does this relate to?
Tags (also called labels or tracking categories) are flexible labels you apply however you want. Unlike categories, which usually follow a fixed hierarchy, tags can stack. One transaction can have multiple tags. Tags answer: What else do I want to know about this?
The practical difference: if you're organizing by structure, use categories. If you're organizing by project, campaign, or something you didn't anticipate when you built your chart, use tags.
How to Use Categories Effectively
Categories work best when you have clear, repeating organizational divisions. Common structures include:
By location: London office, Manchester office, Remote team
By department: Sales, Marketing, Operations, Admin, R&D
By business line: Consulting, Products, Training
By project: Project Alpha, Project Beta
Pick whichever structure gives you the management information you actually need. If you don't care about office-by-office profitability, don't create location categories. The more categories you create, the harder it is to apply them consistently. Start with the one dimension that matters most.
Once you've set up categories, apply them consistently. Every transaction should have a category assigned. Your accounting software should let you generate reports filtered or grouped by category — departmental P&Ls, location-based reports, business line analysis. That's where the payoff comes: instead of digging through hundreds of transactions, you can see at a glance whether your Manchester office is profitable or which product line is carrying the weight.
When setting up categories, define them based on the questions you'll actually ask. "Is the Manchester office profitable?" is a sensible question that warrants a category structure. Be disciplined about the dimensions you choose. The more you stay focused, the more useful the data becomes.
How to Use Tags Effectively
Tags are looser and more flexible. You can create them on the fly, apply them loosely (you don't have to tag every transaction), and use multiple tags on a single transaction. This makes them powerful for:
By project or client: "Client-ABC," "Project-Launch," "Website-Redesign"
By campaign: "Q1-Campaign," "Google-Ads," "Trade-Show-2027"
By funding source: "Grant-Funded," "Self-Funded"
By strategic priority: "Essential," "Discretionary," "Testing"
Tags excel at supporting ad hoc questions — the ones you didn't anticipate when you built your chart of accounts. Mid-year, you decide you want to track spending on a particular initiative. Create a tag, start applying it, and you don't have to restructure anything. That's the flexibility tags give you.
A single expense might be tagged as "Marketing," "Q1-Campaign," and "Google-Ads" — three tags, one transaction. This means you can filter for total marketing spend, or total Q1 spending across all departments, or specifically Google Ads costs. Tags multiply the ways you can slice your data.
Use a consistent naming convention — decide whether it's "Google-Ads" or "GoogleAds" or "google_ads" and stick with it. Your software won't merge them for you; they're separate tags even though they mean the same thing.
Real-World Examples
Here's how this works in practice.
Multi-location profitability. You run two offices and need to understand which is profitable. Use categories: London, Manchester. Every transaction gets assigned to a location. Generate a P&L for each location separately. You'll see immediately which office is carrying costs and which is generating margin.
Marketing channel ROI. You spend on Google Ads, social media, email, and events. Your chart of accounts has one "Marketing" expense account. Create tags for each channel. Tag every marketing expense by channel. At month-end, filter by tag to see spend per channel. Compare this against revenue that came from each channel. Now you can see which channel is genuinely profitable.
Grant-funded projects. Many UK grant schemes, including those listed on gov.uk's business finance support finder, require ring-fenced financial reporting. Create a tag for the grant: "Grant-2027." Tag all income and expenses related to it. At reporting time, filter by the tag to produce the exact expenditure report your funder requires.
New product launch. You're launching a new product and want to track total investment. Tag all costs associated with the launch across different accounts — development, legal fees, marketing, packaging. Tag is "New-Product-X." At any time, filter by that tag to see total investment to date. Once the product is live, you can track profitability using the same approach you'd use for a subscription business.
E-commerce by channel. If you sell through multiple channels — website, marketplace, retail partnership — tag each transaction by channel. Your e-commerce accounting becomes much clearer when you can see profit per channel rather than just total profit.
Best Practices That Work
Be consistent. Tags and categories only work if applied consistently. If half your transactions are untagged, your reports are incomplete. Establish naming conventions and stick with them. Assign someone ownership of the tagging system — someone who creates new tags when needed, merges duplicates, and ensures the team is applying them the same way.
Keep it manageable. More categories and tags isn't better. Ten categories create confusion; two or three dimensions you actually use creates insight. Start with what you genuinely need for decision-making. Add more only if there's a clear reason.
Review regularly. Every quarter, audit your tags and categories. Are they still relevant? Are there duplicates? Gaps? Is the team applying them consistently? If not, merge duplicates and update the reference guide everyone uses.
Use your software's features. Modern accounting software makes this straightforward. When you transition from spreadsheets to accounting software, look for required-field enforcement (force a category before saving), default rules (auto-apply tags based on supplier or amount), bulk editing, and filtered reports. Relentify's accounting platform supports flexible tagging and categorisation with reporting that lets you slice your financial data across multiple dimensions.
Document your system. Create a one-page reference guide explaining your category structure and tag conventions. Share it with anyone who records transactions. New team members will apply the system correctly from day one.
Frequently Asked Questions
Do I have to use both categories and tags? No. Many small businesses use one or the other. Use categories if you have clear organizational divisions (locations, departments). Use tags if you need flexibility and ad hoc analysis. Some businesses use both: categories for structure, tags for campaigns or projects.
How many categories should I create? Start with two to four. If you have multiple locations, one category per location makes sense. If you have distinct departments, one per department. More than that and you'll struggle to apply them consistently. Add a new category only when you have a clear reporting need that your current structure can't address.
What if I forget to tag a transaction? It happens. If it's important, go back and tag it. If you find yourself forgetting frequently, either your tagging system is too complex or not worth the effort. Simplify or abandon that dimension. The best tagging system is one you'll actually use.
Can I change tags after I've created them? Yes. You can merge duplicate tags, rename tags, and re-tag transactions in bulk. Most accounting software lets you do this. Just be aware that historical reports will change if you're retroactively altering tags, so document what you've done.
How do tags and categories show up in my financial statements? They usually don't. Your standard P&L and balance sheet are based on your chart of accounts. Tags and categories power filtered reports — custom P&Ls filtered by location, or a spend summary filtered by project tag. Your accounting software usually has a reporting section where you can build these on demand.
Should I tag revenue or just expenses? Tag both if your software allows it and you have a reason. If you want to know which marketing campaign drove revenue, tag the invoices from that campaign. If you want to track grant-funded income separately from regular income, tag both sides. The more consistently you tag, the more powerful your analysis becomes.
What's the difference between a category and a department? They're the same thing in most accounting software. A category could represent a department (Sales, Operations), a location (London, Manchester), or a business line (Consulting, Products). It's just an organizational dimension.
Can I use tags for tax compliance? Tags can help you organize data for tax purposes, but they're not a substitute for proper accounting structure. Your chart of accounts is what HMRC cares about. Tags are for internal analysis and reporting.
If you're not currently using tags or categories, start with one dimension that would be most useful: location-based profitability, project cost tracking, or marketing channel ROI. Apply it to new transactions going forward. Once the habit sticks, add a second dimension if it's useful. The point is to start. Even a single well-maintained category or tagging structure provides more insight than no structure at all.
Try Relentify's accounting software free for 14 days. You can set up your first category structure and see the difference in your reporting immediately.