Best Invoicing Software for Consultants: 10 Tools

Consultants rarely love invoicing, but it's how the work turns into income. The right tool makes it quick to bill, reminds clients who are late and keeps your records tidy for tax time.

The ten tools below are listed alphabetically and in no particular order, from free invoicing apps to full accounting software. Each description comes from the tool's own site, read this week. For a checklist of features worth having, see my guide to invoicing app features for freelancers.

Invoicing software for consultants at a glance

In the free plan column, Yes means the tool's own site describes free use or a free plan, Trial only means a time-limited trial and No means neither is stated on the pages we read.

Tool	Type	Good for	Free plan
Bonsai	Client business suite	Clients and invoices together	Trial only
FreshBooks	Invoicing and accounting	Consultants who want full accounting	No
Harvest	Time tracking and invoicing	Billing by the hour	Trial only
Hiveage	Invoicing	Simple invoicing at no charge	Yes
Indy	Freelance business tools	Freelancers starting out	Yes
Invoicely	Online invoicing	Free online invoices	Yes
Moxie	Freelance business suite	Running the whole client process	Trial only
Plutio	Business automation	Automating a service business	Trial only
Xero	Accounting software	Consultants with an accountant	No
Zoho Invoice	Free invoicing	Free invoices with tax details	Yes

Ten invoicing tools for consultants

Bonsai

Best for: Independent consultants who want business management software that keeps clients, projects and invoices together in one place.

FreshBooks

Best for: Advisers who want invoicing, expenses and full accounting in one tool their accountant will recognise.

Harvest

Best for: Consultants and small firms who bill by the hour and want tracked time turned into invoices without retyping.

Hiveage

Best for: Solo consultants who want simple, free invoicing software for small businesses with card payments built in.

Indy

Best for: New independent consultants who want a simple CRM and business tools built for freelancers, starting for free.

Invoicely

Best for: Part-time consultants who send a handful of invoices each month and want a free, simple online tool to manage them.

Moxie

Best for: Busy consultants who want an all-in-one freelance business management system to run client work from one workspace.

Plutio

Best for: Coaches and consultants who want one app to run, grow and automate their service business, with automations that follow up for them.

Xero

Best for: Consultants whose accountant works in Xero and want invoices, bank feeds and tax-ready books in one place.

Zoho Invoice

Best for: Freelance advisers who want free, professional tax invoices from a well-known accounting software brand.

When the law requires an invoice in the UK

Here's a detail UK consultants often don't realise. GOV.UK says you need to give a customer an invoice by law if both you and the customer are registered for VAT, and that an invoice isn't the same as a receipt.

If you're VAT-registered in the UK, pick invoicing software that adds the required VAT details for you, so every invoice is right first time. Even if you're not registered, clear invoices with numbers, dates and terms make life easier for everyone.

Hourly, project or retainer billing?

Hourly consultants need time tracking that turns into invoices without retyping. Project-based consultants need milestones, deposits and estimates that convert into invoices. Retainer clients need recurring invoices that go out automatically on the same day each month.

Many tools handle all three, but each has a strength. Think about how most of your income arrives and choose the tool that makes that billing method easiest.

An invoicing routine that keeps cash flowing

1. Agree payment terms in writing before you start any work.
2. Send invoices the day work is delivered or a milestone is reached.
3. Include a clear reference, due date and how to pay.
4. Set automatic reminders before and after the due date.
5. Offer online card or bank payment to make it easy.
6. Review outstanding invoices every Friday.

Details every consultant invoice needs

• Unique invoice number. In a sequence you can track.
• Clear description. What the work was and when it was done.
• Due date and terms. Agreed before the work started.
• How to pay. Bank details or a payment link.

Retainers and recurring work

Retainers are great for steady income, but they're easy to forget to invoice. Set them up as recurring invoices that go out automatically, and add a short note of what was delivered that month. Clients feel the value, and you never miss a billing cycle. It's simple, you'll look organised and clients won't need to ask what they're getting.

Keeping invoices and proposals connected

When your proposal, contract and invoices live in the same tool, it's easy to check what was agreed and bill exactly that. That consistency avoids disputes and makes it simple to show a client what they signed up for if questions come up later.

Do you make invoicing software? Tool makers can ask to be considered for a featured place on this list.

My plain advice on invoicing software for consultants

Make paying you the easiest thing your client does all week. Online payment links, clear due dates and polite automatic reminders do more for your cash flow than chasing by hand. Choose a tool that does those three things well.

If you work with an accountant, check which tool they use before you decide. Invoices feed straight into your books, and a tool that connects to their software saves you both time. My guide on how to create an invoice template that speeds up payment shows the details that help.

Frequently asked questions

What is the best invoicing software for consultants?

It depends on how you bill. Hourly consultants need time tracking, project consultants need milestones and retainer clients need recurring invoices.

Is there free invoicing software for consultants?

Yes. Several tools on this list describe free plans or free use. Check the table.

Is an invoice a legal requirement in the UK?

GOV.UK says you need to give a customer an invoice by law if both you and the customer are registered for VAT.

Can invoicing software chase late payments?

Many tools send automatic reminders before and after the due date, which saves awkward emails.

Should I use invoicing or accounting software?

Invoicing tools are simpler, while accounting software adds bookkeeping and tax features. Many consultants start simple and upgrade later.

Can clients pay invoices online?

Most tools let clients pay by card or bank transfer from the invoice, which usually speeds up payment.