Invoice vs receipt vs estimate: what each document actually proves
These four words get used loosely, and in Korean the confusion runs deeper because 인보이스, 청구서, 영수증 and 세금계산서 map onto English terms unevenly. This page defines each one by what it proves, not by what it looks like, and adds the Korean specifics — 간이영수증, 세금계산서, freelance withholding — that decide which document you actually need.
Four documents, four different proofs
The fastest way to tell these apart is to ask what each one would hold up as evidence of, if someone questioned it later.
- Estimate (견적서) proves a price was offered before work started, valid until a stated date — not proof of agreement or payment
- Invoice (청구서) proves a payment is owed, by whom, to whom, and by when — a request, not confirmation it was paid
- Receipt (영수증) proves payment was actually received — issued after money changes hands, the only one of the four that confirms a transaction is closed
- Korean tax invoice (세금계산서) proves VAT was charged and reported to the tax authority — a statutory document, not just a business record
Invoice vs receipt: before and after money moves
An invoice comes before payment and asks for it; a receipt comes after and confirms it happened. If a client has already paid you in full, don't send an invoice with a due date — send a receipt, or an invoice with the amount paid entered so the balance due shows zero. Sending an invoice for money you already received reads as either a mistake or a second request, neither of which helps the relationship.
Korean specifics: 세금계산서, 간이영수증, and the 3.3% rule
A 세금계산서 is the statutory VAT tax invoice, issued electronically through the National Tax Service's Hometax system once a taxable transaction is confirmed. None of the documents this tool generates — invoice, estimate, or statement — is a 세금계산서 or can substitute for one; a VAT-registered business that needs one must issue it separately through Hometax or accounting software.
For small, one-off purchases, a 간이영수증 (simplified receipt) is common. The widely cited threshold is 30,000 won: for a single transaction of 30,000 won or less, a business generally isn't required to hold a qualifying receipt (세금계산서, 계산서, card slip or cash receipt) to claim the expense for corporate or income tax purposes. Above that threshold, the rules get stricter, and — separately — input-VAT credit is a different question from whether an expense is deductible at all; a 간이영수증 alone typically does not support a VAT credit even under the 30,000-won expense rule. Splitting one purchase into several under-30,000-won receipts to dodge the requirement is specifically flagged in Korean tax guidance as improper.
Freelancers and individual contractors paid under a service contract in Korea are commonly subject to 3.3% withholding: the payer withholds 3.3% of the fee (3% income tax plus local surtax) and reports it, rather than the freelancer issuing a 세금계산서. If that's your situation, you typically bill with an invoice or statement and a bank account rather than a tax invoice — which is exactly the kind of document this tool's invoice and statement pages produce.
These are general practices, not a substitute for advice on your specific situation — thresholds, exceptions and reporting deadlines change, so confirm anything that affects a tax filing with a licensed tax professional (세무 전문가 확인) before you rely on it.
Which document do you actually need?
Work backward from the moment you're in. Before a job starts and the price isn't locked in: an estimate. Once the work is agreed or delivered and you want to be paid: an invoice. Once you've been paid: a receipt. Once a taxable business transaction needs to be reported for VAT: a 세금계산서, issued through the proper channel, not any of the documents above.
Frequently asked questions
- Can one document be both an invoice and a receipt?
- Practically yes, if you mark it paid and show a zero balance — but it's clearer to send an invoice before payment and a separate receipt after, especially for larger amounts.
- Is 인보이스 the same word as 청구서 in Korean?
- They overlap in meaning, but in everyday Korean usage 인보이스 leans toward export and international trade documents, while 청구서 is the everyday word for a domestic bill requesting payment.
- Do I need a tax ID / registration number on an invoice?
- If you charge VAT, GST or sales tax, most jurisdictions expect your registration number on the invoice. In Korean business form mode there's a dedicated field for it on both the supplier and recipient blocks.
- What's the 30,000-won rule for 간이영수증 exactly?
- For a single transaction of 30,000 won or less, a business generally doesn't need a qualifying receipt to claim the expense for income or corporate tax. It does not, by itself, give you a VAT input credit, and splitting one purchase into smaller receipts to stay under the limit is not accepted practice. Confirm current thresholds with a tax professional.
- As a freelancer paid with 3.3% withholding, do I issue a 세금계산서?
- Usually not. The payer withholds 3.3% and reports it; you typically bill with an invoice or statement and receive the net amount by bank transfer rather than issuing a tax invoice yourself. Confirm your specific case with a tax professional if you're registering as a business.
- Does this tool generate a Korean tax invoice (세금계산서)?
- No. It generates invoices, estimates and statements, including a Korean business-form layout with a VAT line — but a 세금계산서 must be issued through Hometax or licensed accounting software.
Content last reviewed: 2026-09-03