Office admin, bookkeeper or AI? What each costs a small trade firm

A part-time office admin on 20 hours a week at the National Living Wage costs a small trade firm about £14,700 a year once employer National Insurance and pension are added. A bookkeeper doing monthly books often costs far less but only covers the accounts. AI tools sit in between on price. The right answer depends on which jobs eat your evenings.

What does each option do for you?

They cover different work, so compare jobs before prices. An office admin answers the phone, books jobs, raises invoices and chases payment. A bookkeeper records income and costs, reconciles the bank and gets figures ready for VAT and your accountant. An AI back office drafts the paperwork from what you send it and leaves the decisions to you.

If you're not sure where your hours go, list a week of admin first. Our guide to admin hours for tradespeople shows how the firms we spoke to split it.

How much does a part-time office admin cost?

More than the hourly rate. On top of wages you pay employer National Insurance and, for most staff, a workplace pension. Here is the sum for one admin on 20 hours a week at the minimum.

Worked example

True cost of a 20-hour office admin, 2026 to 2027

One admin aged 21 or over, paid the National Living Wage of £12.71 an hour for 52 weeks (holiday is paid).

Wages20 hrs × 52 weeks × £12.71	£13,218
Employer National Insurance15% × (£13,218 − £5,000)	£1,233
Workplace pension, employer share3% × (£13,218 − £6,240)	£209
Cost of employing them for a year	£14,660
Cost per hour they work£14,660 ÷ (20 × 47.4 weeks)	£15.46

An experienced admin who can price work or deal with merchants will expect more than the minimum. Payroll, holidays and sick pay become yours to run, and the Statutory Sick Pay rate for 2026 to 2027 is £123.25 a week or 80% of average weekly earnings, whichever is lower.

What does a bookkeeper cost, and what do you get?

Bookkeepers usually charge a monthly fee or an hourly rate, and the price depends on how many transactions you have and whether VAT and payroll are included. One electrician we spoke to was paying £75 a month. Get two or three quotes locally for your own volume.

The catch is scope. A bookkeeper works from the receipts and bills you hand over, so if those arrive late or in a carrier bag, the books are late too. A bookkeeper is the right buy when your problem is the accounts. They won't help with quotes, calls or chasing.

What does AI cost, and what does it still need from you?

AI tools range from general chat assistants with a monthly subscription to back-office services built for trades that connect to your accounts software. Check each vendor's own pricing page, because prices change. Nexley, for example, is £799 a month with a 7-day free trial and no contract, as of October 2026.

What AI needs from you is the rules: your rates, markup, terms and suppliers. Without them it guesses. Write them on one page first; our owner bottleneck guide has a template. You also stay the approver. Nothing should go to a customer until you've read it.

The electrician paying £75 a month dropped his bookkeeper once supplier invoices went into Xero automatically with price-rise checks. That worked for him because the bookkeeping was mostly data entry. A firm with payroll, CIS and VAT returns may still want a bookkeeper or accountant alongside any tool.

What does your own time cost?

Usually more than any of the options. Most owners do admin in the evening at no visible cost, but those hours have a price: either jobs you didn't quote or time you didn't get home. Use your charge-out rate, or what you'd earn on the tools.

Calculator: What admin costs you

Admin hours a weekEvenings and weekends counthrs

Weeks a year

What your hour is worthYour charge-out rate£

A year–

Your numbers, not a promise. Change any figure to match your firm.

At 10 hours a week for 48 weeks at £45, that's £21,600 a year. A firm with the owner doing 16 hours a week, two full days, is spending £34,560 of time on admin at the same rate.

So which should you pick?

Pick by the job that costs you most:

• Calls and customers are the problem. Phones ringing on site, enquiries going cold: an office admin in office hours, or an answering setup. See how to stop missing enquiries on site.
• The books are the problem. Xero is months behind and VAT is a scramble: a bookkeeper.
• Paperwork is the problem. Quotes, invoices, orders and chasers stacking up in the evening: AI drafting with you approving.
• All three. Many firms combine them: AI for the daily paperwork, a bookkeeper or accountant for the year-end and returns.

The figures above are one admin on the minimum wage, the one bookkeeper fee we were told about, and Nexley's list price. Your quotes will differ, so swap in your own.

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Where Nexley fits

Nexley is the AI back office for UK trade firms: five AI assistants run your tenders, quotes, buying, scheduling and invoicing. It connects to the tools you already work in, you run it all from WhatsApp, and you approve everything. £799 a month.

Nexley does the paperwork side of an office admin over WhatsApp: it drafts quotes from your voice notes, files supplier bills, writes invoices and payment chasers, and sends each one back for you to approve. It doesn't replace your accountant for returns or year-end, and nothing goes out until you say yes.

Start 7 days freeSee back office automation

Common questions

Sources

1. GOV.UK: National Minimum Wage and National Living Wage rates
2. GOV.UK: Rates and thresholds for employers 2026 to 2027
3. The Pensions Regulator: Earnings thresholds
4. GOV.UK: Workplace pensions, how to enrol staff
5. GOV.UK: Holiday entitlement

Every rule, rate and date above was checked against these sources on the date shown at the top.