Your FEL invoice can show Q11,200 while the bank credit is Q10,520. That gap is often ISR withholding on the net plus VAT withholding on the VAT line: not a “bank error.” If you quote as if the gross invoice hits your account, cash runs short.
Short answer
| Step | Action |
|---|---|
| 1 | Start from the net amount (before VAT) |
| 2 | Reference VAT ≈ net × 12% |
| 3 | Gross invoice = net + VAT |
| 4 | ISR withholding (editable) ≈ net × ISR rate |
| 5 | VAT withholding (editable) ≈ VAT × VAT-withholding rate |
| 6 | Net deposit = gross invoice − both withholdings |
Figures below use the same educational engine as Calcufast’s Guatemala ISR & VAT withholding calculator (example assumptions: 12% VAT, 5% ISR on net, 15% of VAT withheld). Estimates only: real rates depend on taxpayer type, operation, and withholding agent. Editorial check: 12 Aug 2026.
This is not a substitute for a CPA or Guatemala’s tax authority (SAT). Confirm rates, thresholds, and withholding certificates with your client or advisor before you quote or file. Start at the SAT portal and SAT’s VAT web withholding materials.
Formula (calculator model)
VAT = Net × (vat_rate / 100)
Gross_invoice = Net + VAT
ISR_withholding = Net × (isr_rate / 100)
VAT_withholding = VAT × (vat_wh_rate / 100)
Total_withheld = ISR_withholding + VAT_withholding
Net_payment = Gross_invoice − Total_withheld
With these example percentages, the cash gap versus the invoice total is ISR + VAT withholding, not the full VAT amount.
Case 1: Q10,000 before VAT
| Line | Amount |
|---|---|
| Net goods/services | Q10,000.00 |
| VAT 12% | Q1,200.00 |
| Gross invoice | Q11,200.00 |
| ISR 5% on net | Q500.00 |
| VAT withholding 15% of VAT | Q180.00 |
| Total withheld | Q680.00 |
| Estimated net payment | Q10,520.00 |
If you budgeted the full Q11,200, you are Q680 short on payment day. Withholding is not always a final tax loss: it can be creditable later: but today it is not in your account.
Case 2: Freelancer Q3,500 before VAT
| Line | Amount |
|---|---|
| Net | Q3,500.00 |
| VAT 12% | Q420.00 |
| Gross invoice | Q3,920.00 |
| ISR 5% | Q175.00 |
| VAT WH 15% | Q63.00 |
| Net payment | Q3,682.00 |
Cash gap: Q238. On thin margins that is real working capital. Cross-check the same figure in the withholding calculator and freelance pricing.
Case 3: ISR only (no VAT withholding)
Same Q10,000 net, 12% VAT, 5% ISR, 0% VAT withholding:
| Line | Amount |
|---|---|
| Gross invoice | Q11,200.00 |
| ISR only | Q500.00 |
| Net payment | Q10,700.00 |
Versus case 1 you keep Q180 more liquidity. Defaults in a WhatsApp screenshot are not a substitute for the client’s actual withholding agent rules: that is why every rate in the UI is editable.
Case 4: Large supplier invoice Q25,000 net
| Line | Amount |
|---|---|
| Net | Q25,000.00 |
| VAT 12% | Q3,000.00 |
| Gross invoice | Q28,000.00 |
| ISR 5% | Q1,250.00 |
| VAT WH 15% | Q450.00 |
| Total withheld | Q1,700.00 |
| Net payment | Q26,300.00 |
Q1,700 stuck in withholding on one payment can fund payroll or inventory. If gross margin is 8–12%, quoting “to the edge” without modeling withholdings can leave cash red even when annual P&L looks fine.
Sensitivity table (fixed Q10,000 net)
| Scenario | Rates (VAT / ISR / VAT-WH) | Net pay | Gap vs invoice |
|---|---|---|---|
| No withholding | 12 / 0 / 0 | Q11,200 | Q0 |
| VAT WH only | 12 / 0 / 15 | Q11,020 | Q180 |
| ISR only | 12 / 5 / 0 | Q10,700 | Q500 |
| Initial example | 12 / 5 / 15 | Q10,520 | Q680 |
| ISR 7% + VAT WH 15% | 12 / 7 / 15 | Q10,320 | Q880 |
Move one dial in the calculator before you send the quote.
Expensive mistakes
- Treating invoice total as bank deposit. Client pays invoice − applicable withholdings.
- Assuming “always 5% and 15%.” Those are editable educational defaults, not a universal SAT tariff for every activity.
- Ignoring small-taxpayer / regime differences. Pair with small taxpayer and Guatemala VAT.
- Mixing invoice withholding with payroll. Employee take-home is a different path: net salary Guatemala and Guatemala income tax (ISR).
- Skipping the withholding certificate. Without it, your accountant reconciles blind.
Which calculator to use
| Question | Tool |
|---|---|
| What hits my account on this invoice? | ISR & VAT withholding |
| How much VAT is in the price? | Guatemala VAT |
| Annual/monthly activity ISR? | Guatemala income tax |
| Which ISR regime fits? | ISR regime comparison |
| VAT credit vs debit? | VAT credit/debit |
| What should I charge as a freelancer? | Freelance pricing |
| Payroll take-home? | Net salary Guatemala |
Related reading: income tax guide for salaried workers, Guatemala tax guide (ISR/VAT/IUSI).
FAQ
In Calcufast’s educational model, ISR withholding applies to the net (pre-VAT) amount and VAT withholding to the VAT line. Your live case may differ: confirm with the withholding agent or your CPA.
They may be required to withhold ISR and/or VAT and remit it to SAT. Deposit ≈ invoice − applicable withholdings. Request the withholding certificate.
No. They are editable defaults so you can stress-test cash impact. SAT rules and the specific operation decide what actually applies.
Yes, as order-of-magnitude planning. Adjust rates and verify your invoice type. Also use the small taxpayer calculator.
Not always. It may be a prepayment or creditable amount. What is certain: it reduces cash on collection day. Model liquidity separately from annual profit.
No single rule. You should know net payment so you do not quote below your cash cost. Many freelancers show price + “subject to client withholdings.”
Next step
- Open the Guatemala ISR & VAT withholding calculator.
- Paste your real net and the rates your client confirmed.
- Screenshot net payment and negotiate with numbers, not vibes.
Expanded 12 August 2026 with cases from the live tool engine. Rules and rates can change: always verify on official SAT sources.