GST Invoices and Card Settlement for Interior Designers

Published: 27 October 2026

Category: how-to-guides | cardbuzz

Tags: interior design, GST invoices, card settlement, reconciliation, design studio accounting, tax invoices, interior project billing

For an interior design studio, the job is not finished when the home looks beautiful. The invoice must be correct, the tax treatment must be right, the card payment must be settled, and the books must show the same story in all three places. When any of those records disagree, the studio faces client queries, tax complications, and month-end reconciliation work that could have been avoided with a cleaner process. Good invoicing and settlement discipline is not back-office trivia: it is what keeps a growing studio trusted and auditable.

This guide explains, in practical terms, how GST invoices, card settlements, and reconciliation fit together for interior design work, without offering tax advice for any specific case.

What Belongs on an Interior Design Invoice

A proper tax invoice for a design project should identify the supplier and the client, describe the work and materials supplied, and show the amounts clearly. For a typical project, that means separating design services, carpentry and site work, and materials or bought-out items, where the studio's invoicing practice treats them separately, and showing tax amounts and the total payable in a way the client can follow. A single lump sum with no breakdown invites questions, especially when the client later claims the cost against business expenses or a housing loan.

The invoice should also carry the project reference, the site address, and the milestone it covers, so a client can match each invoice to the right stage.

How Card Settlement Actually Works

When a client pays by card, the money does not arrive instantly in the studio's bank account. The transaction is authorised at the time of payment, batched with the day's other card transactions, cleared through the network, and then settled into the studio's account after the acquirer's settlement cycle. The amount settled is the gross card sales minus the acquirer's fees, unless the studio has an arrangement where fees are debited separately.

That timing gap is why reconciliation matters. A milestone paid for on one day may appear in the bank several working days later, and fees may appear as a separate debit, so a studio that does not link payment date to settlement date will repeatedly think payments are missing when they are merely in transit.

Reconciling Card Sales to Bank Credits

Reconciliation is the daily or weekly habit of matching three records: the studio's project and invoice list, the terminal or payment gateway report, and the bank statement. Each card payment should be traceable from the invoice, through the terminal batch or link record, to a bank credit, with fees accounted for separately.

Each day, the office checks that the terminal batch was settled and link payments confirmed. Each week, it matches settled amounts to bank credits and investigates unmatched items promptly rather than at month end. For a studio running several sites at once, a single project ledger that shows every payment type against every milestone is what makes this habit possible.

Refunds, Credit Notes, and Adjustments

Refunds and adjustments need the same discipline as original invoices. When a client cancels part of a project, returns an item, or receives an agreed price adjustment, the studio should issue the appropriate credit document and process the card refund against the original transaction where possible. That linkage is what lets the client, the bank, and the studio's own books agree about what was reversed.

Credit documents should reference the original invoice number and state plainly what was adjusted and why. A vague credit note helps nobody, and it creates exactly the kind of mismatch that surfaces months later during an audit or a loan verification.

Deposits, Advances, and Staged Invoices

Interior projects with staged payments need careful invoice handling. A booking invoice, a progress invoice, and a final invoice should each show what stage they cover and what balance remains, so that the client is never asked to pay twice for the same stage and the studio never loses track of what is still due. The final invoice should summarise the whole project, showing earlier payments and the remaining balance, so the client can see the complete picture in one document.

Common Reconciliation Problems and Fixes

Several problems recur across design studios. Terminal batches left unsettled at day end delay settlement and confuse the next day's totals, so settling daily is a simple fix. Project references missing from link payments make matching slow, so including the reference in every link description is worth the effort. Cash, card, and bank-transfer payments for one project recorded in different places create a fragmented record, so a single project ledger that shows every payment type is the remedy.

Another common issue is treating the net settled amount as the sale value. The sale value is the gross amount invoiced, and the acquirer fees are a separate business cost. Recording only the net amount understates revenue and distorts both management accounts and tax records. Gross sales, fees, and net settlement should each have their own line in the books.

Closing Thoughts

A studio that invoices clearly, settles batches daily, and reconciles weekly will find its accounts tell the same story as its projects.