Invoicing Software for Professional Services

Coretime offers invoicing and billing software for professional services that turns tracked time and expenses into accurate, professional invoices. Whether you bill hourly, by project, or by milestone, Coretime’s invoicing software reduces manual entry, cuts errors, and helps you get paid faster.

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Users consistently report high satisfaction with Coretime, highlighting its accuracy, reliability, and user-friendly interface for invoicing.

Turn Hours into Income with Coretime Invoicing

As a professional service invoice solution and leading invoicing software for small business UK, Coretime streamlines the process of generating and managing invoices, making it easier for your business to get paid on time. Whether you’re billing clients for hourly work, fixed rates, or projects, Coretime helps you create professional, accurate invoices quickly and efficiently.

Effortless Invoice Creation with Invoicing Software

Generate detailed, professional invoices from tracked time, expenses, or project milestones with just a few clicks. Coretime’s invoicing software for professional services automatically pulls accurate data from timesheets and expense records, reducing errors, speeding up billing, and helping you get paid faster.

Customisable Billing Templates for Professional Services

Personalise invoices with your company logo, terms, and branding to create a professional appearance every time. Coretime offers custom invoice templates for projects and is recognized as the best invoicing software for consultants, helping you present polished, professional invoices that impress clients.

Billable Hours & Expense-Driven Invoices

Automatically pull billable hours and expenses directly from timesheets and project entries with Coretime’s cloud-based invoicing software, allowing you to easily generate invoices from timesheets.

Recurring Invoicing for Long-Term Projects

Set up recurring invoices for ongoing projects with Coretime’s recurring invoicing software and let it streamline your project invoicing, handling the rest automatically.

Flexible Billing Rates

Accommodate different billing rates for various clients, employees or projects ensuring flexibility to your invoicing structure

Client-Specific Invoicing Details

Tailor invoices to each client, including project descriptions for a personalised approach.

Invoicing Tracking & WIP Forecasting

Coretime’s advanced Work In Progress tracking functions and Fee Forecasting capabilities ensures invoices are issued at the right time for the right value.

What Our Clients Say About Coretime Invoicing

“Invoicing is also made much easier. … Coretime automatically assigns the correct hourly rate … while also ensuring that the total is assigned to the correct project.” 

Amanda Godwin, GWP’s Management Accountant

surveying project management and WIP reporting in Coretime software

Why Professional Services Choose Coretime for Invoicing?

The Logical Choice: Coretime is professional services invoicing software that connects timesheets and expenses with invoice production, WIP management, debtor control, and financial reporting.

Accuracy and Transparency

Eliminate billing errors by automatically syncing with timesheets and expenses.

Time-saving Automation

Save time on manual data entry and invoice generation.

Seamless Integration

Coretime integrates with your Accounting software ensuring smooth operations across your entire business.

Financial Clarity

Because Coretime is a fully integrated system, Project Managers can all see this financial information themselves without having to ask the Accounts team.

Stop Project Scope Creep

  • 73% of Professional Services projects experience scope creep
  • Only 31% of businesses successfully bill for scope changes
  • Transparent time tracking ensures comprehensive billing

Latest resources

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  • Blog

03 Feb 2026

What is Resource Utilisation and why it matters more than ever

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  • Blog

27 Jan 2026

Why Your Billing Cycle Is Critical to Cash Flow

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  • Blog

23 Jan 2026

How Finance teams can use Coretime to reconcile Work in Progress (WIP)

Coretime simplifies the process by providing real-time insights, consistent billing rates, and automated WIP reporting helping finance teams close the books faster and more accurately.

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  • Blog

23 Jan 2026

Automated Project Billing with PSA Software

Manual timesheets, disconnected systems, delayed approvals and rekeying data into invoices can slow down cash flow and erode profitability.

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  • Blog

12 Jan 2026

Stop Losing Revenue: Prevent Write-Offs and Missed Billing

For Professional Services businesses time really is money. But far too often, revenue slips through the…

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  • Blog

02 Jan 2026

Why a Timesheet App Is Essential for UK Small Businesses in 2026

For small businesses across the UK, time tracking is no longer optional it’s a critical part…

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  • Blog

19 Dec 2025

Why Consultants Hate Timesheets (and How to Fix It with Coretime Time Tracking Software)

For many consultants, timesheets are the bane of professional life. Sitting down after a long day…

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  • Blog

18 Dec 2025

Why Our Customers Choose Coretime for Smarter Time Management and WIP Tracking

Coretime time tracking and WIP software gives professional services businesses a competitive advantage by simplifying accurate…

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  • Download

11 Nov 2025

Implementing Coretime Without Disrupting Your Business: A Strategic Guide

Discover how to implement Coretime seamlessly. Download our Strategic Guide to Implementing Coretime Without Disrupting Your…

Implementing Coretime Without Disrupting Your Business A Strategic Guide

You’re in good company

Join the growing number of businesses transforming their operations with Coretime, starting from just £20/€25 per user per month. Our customers are strengthening client relationships, gaining real-time project visibility, and driving measurable growth.

Explore their success stories below and see how Coretime can deliver powerful results for your organisation at a price that makes sense.

Aircraft Leasing & Management

We have recently purchased Coretime through Onesys and were impressed with their responsiveness to our original enquiry and to our subsequent questions. The process for understanding what the software could do for us was efficient and straightforward, as was the administration involved in setting-up the account and finalising the agreement.

Aircraft Leasing & Management Logo

Nicola Plummer

Aircraft Leasing & Management

AJA Architects

For us, the main benefit is that our system is now more user-friendly in terms of project managers being able to access information, such as seeing how a project is performing against budget. They can analyse how time is being spent and what proportion of it is earning fees – it’s easy to translate.

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Matt Simpson

AJA Architects

Callisto Consulting

Since purchasing Coretime our time spent on administrative tasks, especially around invoicing has greatly reduced. We can also now respond to Client queries much more efficiently and with a more accurate, trusted response.

Overall the processes that we undertake using Coretime are much quicker and simpler and along with the benefits we’re now receiving in how we can report on our Project data using different parameters, we expect to see a return on investment within a year based on administration time saved.

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Paul Bunyan

Callisto Consulting

R.G. Parkins & Partners

The Coretime system is easy to use, accurate, and has helped to increase our efficiencies, we would absolutely recommend it to other companies in that we find it invaluable.

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David Heron

R.G. Parkins & Partners

GWP Engineering Consultants

Coretime are a real business partner, I find them very helpful, and if I have any questions or queries the support team is there to help me instantly. In short, we’re delighted.

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Amanda Godwin

GWP Engineering Consultants

Caulmert

With staff based at different office locations and sometimes different parts of the world, having Coretime has brought us all together using one easily accessible web based system.

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Donna Milne

Caulmert

JNP Group

Coretime is one of the most important packages within the business and is based on an annual subscription with full cloud access. This is a truly fantastic system and very affordable for a company of our size, it’s a fraction of the cost of some systems such as Autodesk and Microsoft.

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Jamie Seabrook

JNP Group

Deaton Lysaght

Coretime is simply the easiest, yet the most economically advantageous programme that does so much more than just time management. The overall impact of Coretime has improved both productivity and efficiency.

Elizabeth Churchard

Deaton Lysaght

Pete Stead – P+HS Architects

A huge positive for us is the reduction of double entry of information, not having to manipulate information and enter it somewhere else has made such a drastic difference to how we run our business, we can’t imagine not having Coretime now!

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Pete Stead – P+HS Architects

Optima Systems

Coretime provides an excellent service. Their team keeps us regularly updated, which means we always feel informed, supported, and confident that we’re getting the most out of the system.

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Rob Price

Optima Systems

Spark Architects

We will be able to easily track non-billable work such as fee proposals and revisions, track outstanding invoices versus paid, and understand budget versus actuals and profitability at both project level and RIBA stages.

Spark Architects

Wildfowl & Wetlands Trust

It’s cut the time spent on routine administrative tasks and enabled us to be more efficient, which means we can focus more on the actual projects. We can have around 20 live projects on the go at any one time and if a client wants a breakdown of where the time is going, we need to respond almost instantly.

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Monica

Wildfowl & Wetlands Trust