Automated project invoicing: Time and material
If you haven't read our first part of the article series on how to optimise your business through contract types, head on over to [Part 1] to read about Time & material, Continuous payment and Prepaid hours. The rest of the series you find at [Part 3] and [Part 4].

The invoicing types in this post are still Time & material and called On account invoicing with end-balancing and with periodic balancing.
On-account invoicing with end-balancing
This type of invoicing type is a variety of the common Time and material – continuous payment. Large long-term projects use this type of contract, where you have requested payment for part of the total budget before and during project work, but where the final consumption is to be invoiced upon project completion.
At the end of the project, a balancing of what the customers have paid in advance and the total consumption of hours is made.
One example is a time and material contract with an agreed budget of DKK 100,000 for which the customer accepts an advance payment of DKK 50,000, an additional DKK 10,000 half-way through the project and the remaining amount upon completion.
As the contract is based on time and material, the remaining amount is the difference between the cost of the work performed and the DKK 60,000 paid, which is then invoiced before delivering the project.
The advantage with this invoicing type is that you still get paid per hour but have initial capital and invoicing does not have to wait until you have done the work.
The disadvantage may be that you have overestimated the project, so the customer ends up paying too much, which you will have to credit at the end of the project.
On account with periodic balancing
This type of invoicing is typically seen in industries with an ongoing cooperation between customer and supplier. Here, the supplier invoices the customer for a budgeted amount every period in advance – typically monthly or quarterly.
Once the period is over, the prepayment is offset against the value of the actual work performed during the period. The customer then receives an invoice including both this balance and the prepayment for the coming period.
This type of invoicing is often used in consultancies providing ongoing and unspecified assistance for their clients.
Another type of fixed-price contract, the Continuous service contract, is based on well-defined periodic payments. The advantage is that you secure a regular income, which can be included in the budget for the agreed contract period. Please note that if work is done faster than you thought, you will have to pay back the customer.
Both on account invoicing types are demanding to manage manually if you do not use a professional time tracking and automated project invoicing system.