Late invoicing hurts cash flow in field service because the payment clock starts later while wages, fuel and materials keep running. Until the invoice goes out, cash sits in work in progress (WIP) and working capital shrinks.

In field service, the delay starts with a hand-off. An engineer finishes the job on site, the job details travel back to the office, and only then can someone raise the invoice. Joblogic's job management software keeps the job record in one place from visit to invoice. Because that delay happens inside your business, your team can measure it and shorten it.

This guide centres on the days before the invoice exists, plus the UK rules that follow from them. If your invoices go out on time but customers pay late, see why invoice delays are a growth killer.

What is late invoicing and how is it different from late payment?

Late invoicing is a delay between finishing a job and sending the invoice. It happens before the customer has received anything to pay. Late payment comes later in the timeline, when the customer pays after the agreed or legal due date. The two connect through the due date. With no agreed payment date, GOV.UK guidance on late commercial payments says payment is late 30 days after the customer gets the invoice or after you deliver the goods or service, whichever is later.

That rule explains why the gap is yours to carry. With no agreed payment date, the customer's 30 days only start when the invoice arrives, and statutory interest only runs once payment is late, so interest does not compensate you for the days you took to invoice.

How does late invoicing affect cash flow in field service?

Late invoicing holds back cash flow because every day between finishing a job and sending the invoice adds a day before you are paid. The wages, fuel and materials for that job are already spent, so your business funds the work from its own cash until the customer pays.

Late invoicing also feeds a wider problem. In Department for Business and Trade (DBT) late payments research, 40% of surveyed businesses named their own customers being paid late as a driver of the late payments they receive. The September 2024 research rests on 300 telephone interviews across goods, construction, pharmaceutical, insurance and services, so it does not single out field service. DBT's March 2026 consultation response adds that business owners affected by late payment spend 86 hours a year chasing invoices, and puts the cost to the UK economy at £11 billion a year.

How does late invoicing affect days sales outstanding and working capital?

Late invoicing hides inside days sales outstanding (DSO) when you count DSO from the invoice date. DSO is the average number of days it takes to collect payment after a sale. If the count starts at the invoice, the days a finished job waited to be billed never show up. Working capital is the cash and short-term money owed to you, minus the bills you must pay soon. A finished job that has not been invoiced sits in WIP, where nobody can collect or chase it. To see the full delay, add your average days from job completion to invoice to your DSO.

How far does a late invoice push back the due date?

A late invoice pushes the due date back by every day it was delayed. Take a reactive job finished on a Monday. The engineer's job sheet reaches the office on Friday, and the invoice goes out by email the following Monday. If no payment date was agreed, the customer has 30 days from receiving the invoice before payment is late. Paying within those 30 days is on time, yet your cash can arrive 37 days after the work was done. The seven days in the office are the part of that gap your team can shorten.

How do disputed invoices hold up payment?

In DBT's late payments survey, 31% of businesses attributed their own late payments to suppliers to disputed invoices, and 23% to lost or undelivered invoices. Those figures describe businesses as payers, so they show what can hold up your invoice at the customer's end. Weeks after a visit, a site contact has to match labour and parts against memory or a paper trail, and every query sends the invoice back to your team for evidence. Joblogic keeps job notes, photos and customer signatures against the job record, so the evidence behind an invoice is in one place.

How much cash does late invoicing tie up?

The cash tied up by late invoicing equals your average days from job completion to invoice multiplied by the average value you invoice per day. You can work it out from last month's figures in four steps:

1. List every job completed last month with its completion date and invoice date.
2. Count the days between the two dates for each job, then take the average.
3. Divide the total you invoiced last month by the days in the month to get your average value invoiced per day.
4. Multiply the average delay by the daily value to get the cash held back in finished, unbilled work.

Here are round, illustrative numbers for a business that invoices £10,000 a day (£300,000 in a 30-day month):

Cutting the delay from seven days to two moves £50,000 into the bank. Run the sum separately for contract and ad-hoc work, because each has a different hand-off.

How do you measure days from completion to cash?

Days from completion to cash equals your average days to invoice plus your DSO. A seven-day gap and a 35-day DSO means 42 days to cash, and only 35 of those show in a DSO report counted from the invoice date. Alongside the average, value the work that is finished but not yet invoiced and note how old each job is, then review both by work type each month next to WIP and aged debtors.

Joblogic tracks invoice status in the system and can report on invoice payment times, which covers the second half of that figure. The first half comes from the completion and invoice dates held on each job.

Why do field service invoices go out late?

Field service invoices go out late because job details must travel from the engineer on site to the office first. The sheet comes back later, someone checks it, and missing labour, parts or signatures send it back to the engineer. A customer that needs a PO number to approve the invoice adds another search.

DBT's late payments research adds a customer-side cause. 24% of surveyed businesses said late payments they receive come from administrative errors, including failing to log invoices, and the figure was 36% among large businesses, where DBT suggested 'no purchase order, no pay' policies as one possible explanation. An invoice without the customer's PO number can stall for the same reason.

Joblogic's mobile engineer app lets engineers add notes, photos and the customer signature on site, and they can complete visits, forms and signatures offline, with the app syncing once a connection returns. For the leaks that build WIP across multi-site contracts, see our guide to fixing the job-to-invoice process in FM.

When does an invoice legally become late in the UK?

A UK business payment becomes late on the agreed payment date. With no agreed date, it is late 30 days after the customer gets the invoice or after delivery of the goods or service, whichever is later (GOV.UK). Joblogic's invoice templates can carry the due date and payment options, so an agreed payment date appears on the invoice.

Source: GOV.UK, Late commercial payments

Statutory interest on business to business debts is 8% plus the Bank of England base rate. You cannot claim it if your contract sets a different rate, and you send the customer a new invoice when you add it. You can also charge a fixed sum once for each payment, and suppliers can claim reasonable costs each time they try to recover the debt. Joblogic lets you track invoice status and report on invoice payment times, so you can see which invoices are unpaid and how long customers take to pay.

Source: GOV.UK, Claim debt recovery costs

These rules come from the Late Payment of Commercial Debts (Interest) Act 1998 and apply when another business is late paying for goods or a service. The Small Business Commissioner (SBC) offers an interest calculator that works out interest and compensation on an overdue invoice.

Which Bank of England base rate applies to statutory interest?

Statutory interest uses the base rate in force on 30 June for interest that starts to run between 1 July and 31 December, or the rate in force on 31 December for interest that starts between 1 January and 30 June (Rate of Interest Order 2002). The Bank of England held Bank Rate at 3.75% at its 18 June 2026 meeting, so interest on debts that start to run between 1 July and 31 December 2026 is 11.75% a year. On a £5,000 debt that is £587.50 a year, about £1.61 a day, plus £70 fixed compensation. Later Bank Rate changes do not affect debts that start to run before 1 January 2027. The order covers England, Wales and Northern Ireland, and the Scottish Ministers hold the equivalent power for Scotland.

Is there a legal deadline for sending an invoice?

VAT-registered businesses normally must issue a VAT invoice within 30 days of the date of supply, according to HMRC VAT Notice 700/21. Some extensions need no application, such as when you are waiting for invoices from your own suppliers or subcontractors. In other cases you must apply to HMRC in writing. Because Joblogic creates invoices from completed job data, the invoice can go out well inside that window.

What is changing in UK late payment law?

The Commercial Payments Bill [HL] was introduced in the House of Lords on 19 May 2026, completed its Lords third reading on 20 October 2026 and has moved to the House of Commons. It is not yet law and has no commencement date, so the rules above still apply. The Bill and the government's March 2026 consultation response set out the changes:

• A maximum payment period of 60 days (30 days for public authorities), with longer terms void. The government expects this from 2027 at the earliest, with limited exemptions such as contracts between two large companies.
• A right to statutory interest at 8% over base rate written into every commercial contract, with no alternative remedy.
• SBC powers to adjudicate payment disputes and fine persistent late payers.
• A deadline for raising invoice disputes, generally eight days before payment is due, with compensation payable to the supplier if a dispute is raised late or without enough detail.

How can you shorten the gap between job and invoice?

You shorten the gap by capturing job details on site, raising the invoice the day the job completes, and making the invoice easy for the customer to approve and pay.

Capture job details and invoice the same day

Engineers who record labour, parts, photos and the customer signature before leaving site give the office what it needs to bill that day. Joblogic creates invoices from completed job data, calculating timesheets and used parts against the job, and syncs with QuickBooks, Sage and Xero through its accounts integration, so finance checks and posts instead of rebuilding. If you also run the optional paid Joblogic Marketplace apps for projects and equipment hire, approved project and hire invoices sync to Xero and QuickBooks as well, with Sage 200, Sage Intacct and AccountsIQ support added in June. Customers work this way in practice: Tech Asset Management says its team can invoice as soon as a job is complete, and East West Connect describes instant invoicing on completion through its Exchequer integration. Both report quicker cash flow. For feature detail, see our guide to field service invoicing software. Agree who raises each invoice and by when: finance for contract billing, service delivery for ad-hoc jobs as they close.

Make invoices easy to approve and pay

GOV.UK says an invoice must include a unique number, both parties' names and addresses, a clear description, the supply date, the invoice date, the amounts, VAT if applicable and the total owed. Add the customer's PO number and a job description the site contact will recognise, naming the site, asset and visit date, so the approver has nothing to query.

Joblogic can email an invoice with a portal link where the customer can download it or pay securely. Its customer portal lets customers view invoices, pay by debit or credit card, and upload purchase orders or add order numbers, which gives the office the PO number without a chase. The customer portal is part of the Joblogic Enterprise plan.

Chase on a schedule

Agree the steps before an invoice falls due: a reminder before the due date, a call on the day, and a written follow-up once it is overdue. DBT's survey shows why a schedule helps. The most common reason businesses gave for not pursuing late payments formally was avoiding damage to customer relationships (33%), and a fixed schedule takes the personal judgement out of each chase.

What should you do when an invoice stays unpaid?

The SBC's guidance on unpaid invoices sets out eight steps. The main escalation points are:

1. Check the payment terms and the invoice for errors, then send a polite reminder.
2. Contact the customer directly if there is no response, and resend the invoice if they say they never received it.
3. Remind the customer that statutory interest and compensation can be charged, and offer a documented payment plan if they are struggling with cash flow.
4. Send a final demand letter stating the amount owed, a payment deadline and the consequences of non-payment.
5. Consider a collection agency or legal action as a last resort.

Before legal action, a small business with an unresolved dispute with a larger customer can contact the SBC, which may be able to help. The SBC's legal action guidance says it cannot assist with a complaint once legal action has started, and that claims over £10,000 in England and Wales (£5,000 in Scotland and £3,000 in Northern Ireland) should be reviewed with legal advice.

Measure the gap before you fix it

Days from job completion to invoice is the one cash flow measure your team controls from start to finish. Record the gap for last month's completed jobs by work type and run the calculation above, and you have both the cash a shorter gap would release and a baseline to judge any fix against.

If job details are slow to reach the office, book a demo to see Joblogic take a job from engineer sign-off to invoice. For multi-site facilities management work, our guide to closing the SLA gap covers going from completion to cash alongside fewer repeat visits.

Frequently asked questions about late invoicing

What is the impact of late invoicing on cash flow in field service?

Late invoicing holds back cash flow because the payment clock starts later, while wages, fuel and materials for the job are already paid. The finished job sits in WIP, and working capital shrinks. With no agreed payment date, the customer has 30 days from receiving the invoice. A seven-day office delay means cash can arrive 37 days after the work.

What is the difference between late invoicing and late payment?

Late invoicing is a delay between finishing a job and sending the invoice, and it happens before the customer has anything to pay. Late payment is when the customer pays after the agreed or legal due date. With no agreed date, payment is late 30 days after the customer gets the invoice or after delivery, whichever is later, so late invoicing pushes the due date back.

How do you calculate the cost of late invoicing?

Multiply your average days from job completion to invoice by the average value you invoice per day. A business invoicing £10,000 a day with a seven-day delay has £70,000 sitting in completed, unbilled work, and cutting the delay to two days would release £50,000. Run the sum separately for contract and ad-hoc work, because each has a different hand-off.

Does Joblogic invoicing integrate with Xero and Sage?

Yes, Joblogic syncs directly with accounts packages including Xero, Sage and QuickBooks, and its invoicing FAQ also lists Kashflow, FreeAgent and Accounts IQ. It creates invoices from completed job data, calculating timesheets and used parts against the job. The invoice then passes to your accounts package, which removes the step where someone types job sheet details into accounts a second time.

What interest can you charge on a late business invoice?

You can charge statutory interest of 8% plus the Bank of England base rate on a late business to business payment, unless your contract sets a different rate. The base rate used is the one in force on 30 June for interest starting between 1 July and 31 December, or on 31 December for interest starting between 1 January and 30 June. You can also charge fixed compensation of £40, £70 or £100, depending on the size of the debt.