Template vs Software vs Accountant: Which Do UK Online Sellers Actually Need?

At some point in your selling journey, usually around the time you start worrying about Self Assessment, you'll come across the question of how to manage your accounts. A quick search returns three answers: buy an accounting software subscription, get an accountant, or use a spreadsheet template. And most of the content recommending one or the other was written by someone with a stake in the outcome.

This post gives you the honest comparison. What each option actually does, who it's right for, and at what point you need to move from one to the next.

Who the Template Is Right For

The UK Online Seller Tax Template is built for sellers with self-employment income under £50,000 who want to know their tax position accurately throughout the year without paying for software or services they don't need.

It handles the calculations that generic spreadsheets consistently miss. The gross income trap, which catches sellers who use their net bank receipts instead of their pre-fee sale price to check their position against the £1,000 threshold. The PAYE and self-employment interaction, which determines whether your day job has already consumed your personal allowance before any selling profit is taxed. Student loan repayments across all five UK plans. Payment on account in the second year, which doubles the effective January bill for first-time filers who aren't prepared for it, and which our guide to saving the right amount for your tax bill covers in detail.

The key difference between the template and both software and an accountant is the running view. Enter each sale and expense as you go and the dashboard shows your current tax position, what to set aside from every payment, and whether you're approaching any relevant threshold. An accountant files your return once a year in January with no involvement in the eleven months before that, which is when the decisions that actually affect the bill are made.

The template is updated every April when the new tax year begins, so you're always working with confirmed current rates. At £14.99 per year it works in Google Sheets and Excel and produces the exact profit figure that goes on the self-employment pages of your Self Assessment return. You still file the return yourself through HMRC's free online portal, which takes about twenty minutes once you have the right numbers in front of you.

The Real Cost Comparison

A straightforward Self Assessment return for a sole trader with one income stream and clean records costs between £200 and £350 per year at most UK accountancy firms in 2026. The fee is an allowable business expense for a trading online seller, so the after-tax cost at the basic combined rate of 26% is closer to £148 to £259.

Even at the lower end, that is ten times the cost of the template in the first year and every year after that. Over three years an accountant filing your annual return costs £600 to £1,050. Three years of the template costs £44.97.

The argument for an accountant at this level is not cost. It is expertise and representation. A good accountant will spot expenses you missed, catch errors before they become penalties, and handle HMRC correspondence if it arrives. For many sellers those benefits justify the annual fee. For sellers with straightforward affairs and clean records, the template plus HMRC's own free filing portal produces an equally accurate return at a fraction of the price.

Who Needs Monthly Software

Monthly accounting software becomes genuinely necessary at the £50,000 gross income threshold, where Making Tax Digital for Income Tax requires quarterly digital submissions using compatible software. That threshold applies from April 2026 for sellers whose 2024/25 gross income exceeded £50,000.

The threshold drops further. From April 2027 it applies to sellers whose 2025/26 gross income exceeded £30,000. From April 2028 it drops to £20,000. If your gross income is currently between £20,000 and £50,000, software is not yet mandatory but the transition is worth planning for rather than scrambling to meet at the last minute.

Our Making Tax Digital guide covers the thresholds, the quarterly submission process and what compatible software actually needs to do.

Below the current threshold, monthly software is a product sold on convenience rather than necessity. QuickBooks starts at around £12 per month. Xero's entry-level Simple plan, designed specifically for sole traders and MTD compliance, starts at £15 per month. Neither files your Self Assessment directly with HMRC, which means you still need to enter the numbers manually on the HMRC website or pay an accountant to file, making the software an addition to rather than a replacement for that annual filing step.

One important exception worth knowing about. If you bank with NatWest, Royal Bank of Scotland or Ulster Bank, FreeAgent is available free of charge. It includes unlimited invoicing and direct Self Assessment filing, which makes it genuinely competitive for online sellers who qualify. If you bank with one of those three, check FreeAgent before paying for anything else.

When an Accountant Is Worth It

An accountant earns their fee in three specific situations and it's worth being clear about what those are rather than implying you need one for everything.

When you've received a nudge letter or HMRC enquiry. This is not something a template or software resolves. Professional representation from a qualified accountant in a compliance situation is worth every penny. The cost of getting it wrong significantly exceeds the cost of getting it right with help.

When your affairs are complex. Multiple income sources, property income, significant capital gains, overseas income, or a potential incorporation decision all benefit from advice that goes beyond calculation into planning. A template tells you what you owe. An accountant in this situation can tell you how to legitimately reduce it.

The trading allowance versus actual expenses decision is one example where getting it right for your specific numbers can make a meaningful difference to your bill, and our post on when not to claim the trading allowance covers the cases where most people get it wrong.

When your income has grown to the point where decisions are consequential. A seller making £40,000 of net profit from online selling is in a different position from someone making £8,000. At higher income levels the difference between claiming expenses correctly and incorrectly, or between remaining a sole trader and incorporating, can be several thousand pounds a year. That is when the £200 to £350 annual fee clearly pays for itself.

For everyone below those thresholds, with straightforward affairs, clean records and no HMRC contact, the template does the job accurately and at a fraction of the ongoing cost. Accountancy fees for a trading online seller are an allowable business expense, so a seller who does eventually engage an accountant can deduct that fee against their trading profit, reducing the real after-tax cost further.

Get the UK Online Seller Tax Template, £14.99 per year →