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.
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.

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
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
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 resources23 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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Automated Project Billing with PSA Software
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Stop Losing Revenue: Prevent Write-Offs and Missed Billing
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Why a Timesheet App Is Essential for UK Small Businesses in 2026
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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…
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.

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.

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.

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.

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.

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.

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.

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!

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.

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.

Monica
Wildfowl & Wetlands Trust