Best invoicing app for plumbers in 2026

You are a plumber. You are good at plumbing. You did not become a plumber to enjoy sending invoices. But MTD is mandatory, HMRC wants quarterly updates, and you need an app. This is an honest comparison of the tools plumbers actually use.

What a plumber actually needs

• Quotes from your phone while you are still on site.
• Quote to invoice conversion in one tap.
• Expense tracking with receipt photos.
• Mileage logging at HMRC rates: 45p up to 10,000 miles, then 25p above that.
• CIS deduction tracking where relevant.
• MTD-ready records and an easy route into compliant filing software.
• Mobile-first design, not a desktop app squeezed onto a phone.

If you have not sorted mileage yet, read our HMRC mileage guide for sole trader tradespeople. If CIS appears on your jobs, pair this with our CIS deductions explainer.

Honest comparison

FreeAgent (£19/month)

Excellent accounting software with proper MTD filing and a trusted reputation. It can be free via NatWest, which is a genuine advantage. The issue for plumbers is workflow: quoting is basic, CIS is not built into the invoice flow for how subcontractors think, and the mobile experience is more companion app than field-first tool. It is built for accounting quality, not van-door quoting speed.

QuickBooks Self-Employed (£10/month)

A decent all-rounder with recognisable branding. The trade-off is that quoting is limited, CIS usually pushes you into higher tiers (often around £14/month), and parts of the product still feel like an American platform adapted for UK use. On mobile, it can feel like desktop screens compressed into a smaller view.

Xero (from £26/month)

Powerful bookkeeping and reporting, especially with a bookkeeper in the loop. For a sole trader plumber, it is often expensive and more complex than needed day to day. CIS support can depend on tier or extra setup, and the interface is aimed more at finance users than busy people between call-outs.

Countingup (£9.99/month)

Useful blend of business banking with simple bookkeeping. The drawback is the missing quote workflow: no proper quote-to-invoice conversion and no CIS handling for trade-heavy jobs. If your biggest pain is chasing paperwork from site, it may feel incomplete.

Billdr (£9/month)

Full disclosure: we built Billdr for tradespeople. It gives you voice-to-quote, quote to invoice in one tap, receipt scanning with AI categorisation, mileage at HMRC rates, CIS per contractor, FreeAgent MTD integration, AI invoice chase emails, and an accountant pack PDF. Billdr does not replace FreeAgent for MTD filing; it works alongside it so your day-to-day trade admin is easier and your records stay filing-ready.

The numbers

Take a plumber earning £55,000 and completing around 20 jobs per month. If mileage is not claimed properly, 200 miles per week x 52 weeks x £0.45 can mean £4,680 in missed deductions. One chased invoice worth £300 can cover around 33 months of a £9 subscription. One avoided MTD fine of £100 can cover around 11 months.

Admin software should not be judged on subscription price alone. It should be judged on the money it helps you keep, the time it gives back, and the stress it removes when deadlines appear.

Try Billdr free for 30 days. No card. Sign up at billdr.co.uk/signup.