How invoice totals are built
This page explains the handful of money fields on an invoice and how they relate, because that relationship is the whole reason the discount fix is correct.
Business view
Think of a single invoice as a small receipt:
- Subtotal — add up the list price of every procedure on the invoice.
- Discount — subtract whatever the clinic knocked off.
- Tax — add any VAT that applies (many dental invoices are VAT‑exempt, so
this is often zero).
- Total — what's left. This is the figure that flows into the table and the
analytics tiles.
A real example straight from the sandbox (invoice #26):
| Line | Amount |
|---|---|
| Subtotal | ₺500.00 |
| Discount | − ₺75.00 |
| Tax | + ₺63.76 |
| Total | ₺488.76 |
The key takeaway: by the time you see "Total", the discount has already been taken off. That's why, to talk about the discount as a percentage, you first have to add it back.
The analytics bar simply adds up these per‑invoice figures across whatever set of invoices you're looking at, and shows each column as a tile.
Technical view
The canonical formula
packages/server/src/resolvers/mutations/actions/invoices/invoiceUtils.js:205
const total = Number(subtotal.toFixed(2)) - Number(discount.toFixed(2)) + Number(tax.toFixed(2))The same invariant is enforced per line item at invoiceUtils.js:118:
if (Number(item.total.toFixed(2)) !== Number((item.subtotal - item.discount + item.tax).toFixed(2))) hasError = trueSo total = subtotal − discount + tax holds at both the line and invoice level. These computed values are written straight to the invoice row in packages/server/src/resolvers/mutations/actions/invoices/createNewInvoice.js:232 (total, discount, subtotal, discountPercent, …).
The stored Invoice fields
packages/prisma/schema.prisma:2620 (Invoice model) carries, among others:
| Field | Meaning |
|---|---|
subtotal | list price of all procedures, pre‑discount |
discount | money discounted |
discountPercent | stored percentage, computed as discount / subtotal |
tax / taxPercent | VAT amount / rate |
total | subtotal − discount + tax (net of discount) |
paid | amount paid so far |
pendingPayment | amount awaiting confirmation |
insurance | insurer‑covered portion |
diagnosticFee | diagnostic fee component |
released | amount released to clinic revenue |
What feeds the analytics bar
The tiles are fed by the invoicesInfo query.
- Schema:
packages/server/src/schema.graphql:226→ returns[InvoiceGroupInfo]! - Type:
packages/server/src/types.graphql:4059—InvoiceGroupInfoexposes
balanceInvoice, paid, tax, discount, diagnosticFee, pendingPayment, total, balance, released, insurance.
- Resolver:
packages/server/src/resolvers/queries/patientQueries.js:2881— a
prisma.invoice.groupBy({ by: ['balanceInvoice'], _sum: { … } }) that sums each money field over the invoices matching the current filters.
The frontend then reduces those grouped sums into the numbers behind each tile (see the discount fix).
The relationship that makes the fix work
Because total = subtotal − discount + tax:
total + discount = subtotal + tax ← the pre-discount, tax-inclusive base
total + discount − tax = subtotal ← the pre-discount, pre-tax baseThe new denominator total + discount is the first of these. It is the correct "before any discount" figure for a tax‑inclusive view, and it is exact for the many VAT‑exempt invoices where tax = 0.