VAT checks become messy when a customer pays a deposit first and the balance later. Sales may look at the contract total, accounting may check each invoice, and the customer may compare every number against the original offer.
The Qsen VAT calculator helps you add or extract VAT for each payment part and see where the difference comes from.
Split the payment before calculating
Do not calculate the deposit and balance as one line if documents are issued separately. Write down the contract total, deposit amount, balance amount, VAT rate, and whether each document shows a gross or net amount.
For example, a contract is 120,000 including VAT, with a 40% deposit and 60% balance. The deposit is 48,000, and the balance is 72,000. Each part should have its own net amount and VAT amount.
When to extract VAT
Extract VAT when the amount already includes tax. This is common on invoices that say “total including VAT” or “VAT included.” In that case, do not add tax again. You need to find the tax portion inside the gross amount.
Adding VAT on top of an already gross number will make the invoice higher than the contract, which is exactly the kind of mismatch customers notice.
When to add VAT
Add VAT when the starting amount is net. For example, the service price is 40,000 before VAT, and the invoice must show the total payable amount. The calculator gives both the VAT amount and the gross total.
Make sure the offer, contract, and invoice use the same wording. “VAT excluded” and “VAT included” lead to different results.
Reconcile the total
After calculating both parts, add the deposit and balance together. The sum should match the contract total, allowing for rounding rules. If cents do not match, decide whether rounding happens per invoice or on the total.
A simple review table helps: payment part, gross amount, net amount, VAT amount. It makes the deposit and final balance easy to compare.
Mistakes to avoid
- adding VAT to an amount that already includes it;
- comparing a net deposit with a gross contract total;
- ignoring rounding differences;
- using different VAT rates across documents;
- not checking the two payment parts against the contract total.
FAQ
Can I check VAT only on the total contract amount?
Yes, for a high-level check. But if invoices are issued in parts, calculate each part separately.
Why do small rounding differences appear?
They often come from rounding VAT per document instead of rounding only the final total. Decide and document the rule.
How do I know whether the amount is gross or net?
Look for wording in the invoice, contract, or offer. If it is missing, clarify before sending the document.