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.

Coretime invoicing dashboard on desktop showing WIP report with opening balance, closing balance, WIP invoices, WIP credit, and WIP writeoffs for professional services accounting.

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

View all our resources
  • Blog

06 May 2026

The Power of Integrated Time Tracking and CRM for Professional Services

Read more
  • Blog

21 Apr 2026

Best Top 5 Consulting Software for 2026

Read more
  • Blog

13 Apr 2026

The Hidden Cost of Manual Expense Management in Professional Services

Read more
  • Blog

08 Apr 2026

Fixed Fee vs Hourly Billing: Which Makes You More Money? (A Practical Guide)

Compare fixed fee vs hourly billing to see which model drives better project profitability, improves cash flow, and supports stronger client satisfaction.

Read more
  • Blog

02 Apr 2026

The Silent Profit Killers Behind “Good Enough” Time Tracking

Many consulting firms rely on memory, spreadsheets, or basic timers, treating time tracking for consulting firms…

Read more
  • Download

19 Mar 2026

The Coretime Quick Info Pack

If you’re new to Coretime this handy quick information pack from our expert team is the…

Read more
  • Blog

04 Mar 2026

Why Coretime Is Truly Different: A Powerful SaaS Built on Real Partnership

Coretime is more than a timesheet, CRM and project management platform. Discover why our UK-based SaaS focuses on partnerships, customer relationships, and growing alongside the businesses we support.

Read more
  • Blog

01 Mar 2026

Top 5 Time Tracking Challenges (and How to Fix Them With a Time Tracking System)

This article explores the top five time tracking challenges businesses face and shows how a modern time tracking system can reduce write-offs, improve billing accuracy, and turn time data into a genuine strategic

Read more
  • Blog

28 Feb 2026

Why Resource Utilisation Really Matters: Maximise Your Team’s Potential

Learn how to measure efficiency, balance workloads, and make informed decisions to keep projects on track with practical tips and insights for maximising your team’s productivity.

Read more

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.

AJA Architects Logo

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.

Callisto Consulting Logo

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.

R G Parkins & Partners Logo

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.

GWP Consultants Logo

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.

Caulmert Logo

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.

JNP Group Logo

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!

P+HS Logo

Pete Stead – P+HS Architects

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.

WWT Logo

Monica

Wildfowl & Wetlands Trust