Invoice apps are gaining popularity in the UK, but which are genuinely trusted by small businesses? The short answer: not many. There’s no shortage of invoicing tools out there, but they vary hugely in costs and features.

Many companies offer an invoicing app as an added extra to a main offering of bookkeeping, payment services or an online business account.

Some allow you to receive payments directly through the invoice through a payment link, others are not integrated with a payment system. For instance, certain apps just have free invoice templates where you can include your bank details for a manual bank transfer.

We’ve sifted through the options – so what’s the best invoice app for your small business?

Provider Rating Costs To site
Square logo £0/mo
2.5% transaction fee
Intuit QuickBooks logo From £8/mo
1% Direct Debit fee
Zoho logo £0-£21/mo
Transaction fees vary
SumUp £0/mo
2.5% per transaction
Invoice2go From £2.92/mo
From 1.4% + 20p per transaction
Zettle £0/mo
2.5% transaction fee
Who Cost Site
Square logo No monthly fee
2.5% card fee
Intuit QuickBooks logo From £8/mo
1% Direct Debit fee
Zoho logo £0-£21/mo
Card fees vary
SumUp £0/mo
2.5% per transaction
Invoice2go From £2.92/mo
From 1.4% + 20p per transaction
Zettle £0/mo
2.5%per transaction

Square – best features without subscription

Our rating
  • No monthly cost, no contract

  • Integrated card processing at flat rate

  • Next-day deposits in bank account

  • Lots of additional payment tools

We think Square Invoices is the best free invoice app in the UK. It’s easy to use, and you can accept card payments directly through the invoice for 2.5% per transaction. It’s free to use the app and features – you only pay when your client pays online through the email link or URL for the invoice.

Photo: Square

Square Invoices review

Square Invoices has more features than other free invoicing apps.

Payments are deposited in your bank account the next working day, or sooner if you opt for Instant Transfers (costing an extra 1% transaction fee). When you sign up through the simple online form, Square performs identification checks to verify your business and bank account.

It can take up to four working days before the bank account is linked to your Square account, but it’s possible to accept invoice payment sooner, in which case the money is pending in the Square account.

The app allows you to send estimates that convert into invoices when the client accepts the quote. You can also set up recurring invoices, invoice tracking and deposit requests. If the client does not pay directly through the invoice link, you can mark invoices as paid with cash, gift cards, BACS or another payment method.


Monthly cost: Free

Card processing: 2.5% transaction fee

Instant Transfers: Additional 1% of transaction amount

Existing users of Square Reader can already send invoices through the Square Point of Sale app for the same fee. If you have the Square Reader, you can even accept invoice payments directly through the invoice app, if the card is physically processed in the card reader, for the lower fee of 1.75%.

Integrated payments: Visa, Visa Electron, V Pay, Mastercard, Maestro, American Express

Best for: Most accessible solution to receiving invoice payments in your bank account.

QuickBooks – best value for money

Intuit QuickBooks
Our rating
  • From £8/mo

  • Trusted provider in the UK

  • Multi-currency support

  • Great support for HMRC filing

Mostly known for accounting software, Intuit QuickBooks’s invoicing is an integral part of their offering too. All the tiered QuickBooks packages include a variety of business tools, so this is a good choice for managing your books and invoice payments in one place.

QuickBooks Invoice app

The QuickBooks invoice app gives you an intuitive overview of paid and outstanding payments.

If you’re already using QuickBooks for bookkeeping, you might as well use the invoicing features which are included to some extent on all plans. The less dispersed your documents, invoices and receipts are, the more streamlined your admin can be. A plus is that QuickBooks is HMRC-recognised and adheres to the government-incentive Making Tax Digital.

The app is compatible with iPhone, iPad and Android phones and tablets.

The number of invoicing features depend on your plan. The cheapest subscription, called Self-Employed (£8/month), is for sole traders who are not VAT-registered. It includes unlimited invoices by email and the ability to track which ones have been read.

The next tier, Simple Start (£12/month) is for sole traders and companies, whether VAT-registered or not. This plan has more customisation tools, payment tracking, recurring invoices and the ability to accept invoice payments online.

Higher plans do not include more invoicing functions, only more advanced accounting tools.


Monthly fee: £8/mo for Self-Employed, £12/mo for Simple Start

GoCardless payments: 1% transaction fee

PayPal payments: From 3.4% + 20p for domestic cards, from 3.9% + fixed fee for international cards

Stripe payments: Fees through Stripe

You can either accept payments outside the QuickBooks system and mark when invoices are paid, or accept payments through a link on the electronic invoice.

The latter can be done as a GoCardless Direct Debit integration which has no setup fee or monthly costs, just a 1% transaction fee. Other payments, such as PayPal and Stripe, can be integrated too – but integrated payments can only be done on the Simple Start and higher plans.

Integrated payments: PayPal, Stripe (Visa, Mastercard, American Express), GoCardless Direct Debits

Best for: SMEs wanting a complete invoicing and accounting system compliant with HMRC.

Zoho – free invoice generator, more features optional

Zoho logo
Our rating
  • £0-£21/mo

  • No sign-up for free invoice generator

  • Good choice of payment integrations

  • Many features on all plans

Zoho is another all-round accounting system with invoice tools. If you only want to create a PDF invoice to download or send from your phone, you can in fact do that for free – without having to create a login or sign up for anything. You can also pay for the Zoho Invoice app that includes various invoicing features.

Zoho Invoice app

Zoho Invoice is compatible with iOS, Android and Windows phones and tablets.

The invoicing apps are supported on iOS, Android and Windows mobile devices. To be clear: the Invoice Generator app is a separate app you can download and use for free. The free and paid plans described below require the Zoho Invoice app.

The feature-rich Zoho Invoice app has a Free plan limited to one user, with the ability to create transactions for up to five customers.

On the Basic plan (£6/month paid monthly), one user can invoice up to 50 customers. On Standard (£12/month on annual plan), three users can invoice up to 500 customers, and Professional (£18/month on annual plan) allows 10 users to invoice unlimited customers.

All the plans include recurring invoices, estimates, expense tracking, time tracking, multi-currency features, a ‘snail mail’ service and many more features. The pricier plans have more reports, automated workflows and integrations.


Monthly cost: Free (Invoice Generator app) or £0-£21/mo (Zoho Invoice app)

Transaction fees: Through payment processor (PayPal, Square, Stripe, etc.)

Zoho can integrate with a number of payment services, so you can accept payments through the invoice rather than outside the platform. Transaction fees depend on the chosen payment system.

Integrated payments: 2Checkout, Braintree, GoCardless, PayPal, Stripe, Square, others

Best for: Cheap way to start small, with options to expand features later on.

SumUp – better than average for a free solution

Our rating
  • No monthly cost, no contract

  • SumUp processes the card payment

  • Payouts in 1-3 working days

  • POS and remote payment features

SumUp is perhaps best known for their cheap card readers and payment features for small businesses. In recent years, however, SumUp has added a wealth of new features to help merchants receive payments remotely – and this includes digital invoicing.

SumUp Invoices can be created, sent and managed from the SumUp App.

SumUp has no monthly fees or contract term for invoicing, only a pay-as-you-go rate of 2.5% per remote transaction processed. It’s easy to get started too: just sign up on the website, connect your bank account and start invoicing clients from the SumUp App or web dashboard.

SumUp App is actually a payment or point of sale (POS) app. It has a product library, transaction overview and checkout interface for accepting cards, cash, QR code payments or payment links.

In another section of the app, you can create, manage and monitor invoices. There is no limit on how many email invoices you can send, and items from your product library and customers from your customer library can be added to invoices.


Monthly fee: None

Transaction fee: 2.5% for all cards

If you log into your SumUp account on a computer, you can create credit notes too – this is not yet available in the app.

Payouts take 1-3 working days to reach your bank account. With the free SumUp Card (online account and prepaid debit card), you can receive transactions the next day, including weekends.

Integrated payments: SumUp (Visa, Mastercard, Maestro, American Express, Diners Club, Discover, JCB)

Best for: Selection of free payment methods, not just invoices, from the same app.

Invoice2go – big invoicing brand

Our rating
  • From £2.92/mo

  • Annual or monthly billing

  • Settlement takes 2-7 working days

  • Features are better on pricier plans

Invoice2go is a well-known invoice app in the UK, which is understandable given its sleek looks and branding, but it does not offer a free app (barring the 30-day trial). It comes with invoice templates, invoice tracking, multi-currency support, customisation, recurrent billing and estimate-to-invoice conversion.

Invoice2go app invoice

The invoice templates in Invoice2go have several customisation options.

Invoice2go has four plans that can be paid upfront monthly or annually (the latter work out cheapest per month). The cheapest subscription, Lite, includes 50 invoices for the whole year for one user to send to 5 clients on an annual plan (£2.92/month) or 5 invoices per month on the monthly plan (£5.99/month).

The annual Standard plan costs £8.33/month and includes 200 invoices and 200 estimates sent to 25 different clients by one user. The same plan paid monthly (£9.99/month) allows for 20 invoices to 25 clients by the same user.

Higher plans – Advanced and Unlimited – have higher allowances and higher fees of up to £38.99 monthly for unlimited invoices, estimates and clients.

All the subscriptions have advanced features and the ability to receive payments through an integration with Stripe or PayPal.


Monthly fee: £2.92-£25/month for annual plans, £5.99-£38.99/month for monthly plans

Stripe payments: From 1.4% + 20p per transaction (higher plans have lowest rates)

PayPal payments: From 3.4% + 20p per transaction

With Stripe, settlement takes up to 7 working days for UK users, which can be a bit of a stretch for some. PayPal offers quick settlement in your PayPal account, but has high transaction fees.

On the plus side, Invoice2go specialises in invoicing features rather than the general accounting tools that QuickBooks and Xero, for example, offer together with invoicing. However, many users have reported the app is cumbersome to use, the disappearing of features or data saved in the app, and generally the high price for an increasingly problematic user experience.

Integrated payments: PayPal, Stripe, Apple Pay, Google Pay

Best for: Those who don’t mind paying more for a reputable, dedicated invoice app.

Zettle – simplest for face-to-face merchants

Our rating
  • No monthly cost, no contract

  • Zettle handles payment processing

  • Payouts in 1-2 working days

  • Comes with free POS features

Zettle by PayPal (previously iZettle) is well-known for their low-cost card reader and free point of sale (POS) app, but did you know the Zettle Go app can send email invoices too? The invoices are quite simple, and payments are settled directly in your bank account within 1-2 working days.

Zettle invoicing allows you to send email invoices directly from the point-of-sale product menu.

You can add items from a (previously set up) product menu or enter an amount with a custom description. This is all done from the POS interface of the app, where you then have to choose invoicing as the payment method.

The app can save customer details, set a due date, delivery date and customer type (private or company). After sending an invoice, you can view unpaid, paid and credited invoices in the Go app, where it is also possible to manually mark invoices as paid. Apart from that, you can view, resend or cancel invoices and view event history. Payment reminders are sent to the customer after the due date.


Monthly cost: None

Transaction fee: 2.5% for all cards

When the customer receives the invoice, they can pay by link with their Visa, Mastercard or Amex card, and the transaction is then processed by Zettle.

Zettle invoices are quite straightforward, with no templates to choose from and no superfluous functions. If you need complex features like invoice scheduling or design options, this is not for you. But if you don’t mind using a POS app for simple invoices with a pay-as-you-go transaction fee, this is an efficient option.

Integrated payments: Visa, Mastercard, American Express

Best for: Zettle merchants selling face-to-face, but wanting the option to bill by invoice.

Other invoice apps

Lots of invoicing apps are available to the UK, but many have flaws. A few popular options are the Xero Accounting app and PayPal Business app. Either may be the most convenient choice for existing users, but there are issues too with both.

Xero reportedly has a steep learning curve and high monthly cost if you send over five invoices. PayPal Business has high transaction fees and occasional account holds for some users.

Other invoice apps are either created for the North American market, are buggy, have limited features, or use Stripe for payment processing – known for their slow settlement to UK bank accounts (around 7 working days).

Alternatively, you can sign up for an online business current account with invoicing. For example, Tide, Monzo and Monese business accounts have basic invoice features. Starling Bank’s Business Toolkit add-on includes invoicing software, but only in a web browser.