How it works
- ✓ Enter Ireland values in EUR.
- ✓ Engine roi uses model ie-paye-usc-prsi.
- ✓ Inspect the breakdown, not only the headline.
- ✓ Compare a second scenario.
- ✓ Open related tools: Break-even units, Price from margin, Cash runway months, SaaS MRR ARR, Invoice with tax.
Methodology
## Methodology — CAC payback
1. Normalize inputs. 2. Engine `roi` with Ireland pack (ie-paye-usc-prsi). 3. Social rate 0.04, VAT/GST 0.23 from params.ts. 4. Show KPI + breakdown. 5. Continue with Break-even units, Price from margin, Cash runway months, SaaS MRR ARR, Invoice with tax.
### Engine detail (roi) - Uses shipped model ie-paye-usc-prsi for Ireland. - Social / contribution rate in params: 0.04; VAT/GST: 0.23. - Example anchor income ~ €48,000 (illustrative, not a median claim). - Read the breakdown lines, not only the headline KPI. - Re-run after changing one input to see sensitivity.
Worked examples
Baseline — Ireland
Start near €48,000 (credit principal €320,000, rent-like €1,600 if housing). Note the primary KPI for CAC payback, then open related calculators in the same journey.
Sensitivity +10%
Raise the main driver to about €52,800 and compare the delta vs baseline — critical for loans, tax brackets and goals.
Household limit
Push housing or debt share until it exceeds a personal comfort threshold (e.g. 30–40% of net income).
Verify before acting
Re-run with your real Ireland numbers, then confirm with payslip, bank quote or tax authority tools. Educational only.
Common mistakes
1. Headline-only decisions
Read the breakdown and pair with Break-even units, Price from margin, Cash runway months, SaaS MRR ARR, Invoice with tax.
2. Wrong period
Do not mix monthly and annual figures.
3. Ignoring fees
Banks and insurers may add costs beyond pure interest.
4. Wrong country table
This page uses Ireland (IE) parameters, model ie-paye-usc-prsi.
5. Treating estimates as legal notices
Educational only — keep official statements.
Local deep dive
## Complete guide — CAC payback
Ireland · IE · model ie-paye-usc-prsi · EUR.
Primary intent: calculate. Secondary: understand, compare, decide.
PRSI/USC (simplified employee load) / VAT 23%
Revenue — PAYE simplified; USC bands collapsed.
Related: Break-even units, Price from margin, Cash runway months, SaaS MRR ARR, Invoice with tax
### Why this may differ from official numbers May differ from payslip: USC, PRSI and tax credits vary.
### Local context — CAC payback This page is oriented to Ireland (IE), currency EUR, engine `roi`, tax model ie-paye-usc-prsi. Revenue — PAYE simplified; USC bands collapsed. Educational estimate for planning conversations — not a binding tax notice, bank quote, or regulated advice.
FAQ
Is CAC payback updated for 2026?
Yes. Parameters target 2026 for Ireland (model ie-paye-usc-prsi).
Is this official advice?
No. In Ireland, follow the tax authority and licensed professionals. Revenue — PAYE simplified; USC bands collapsed.
Why might results differ from my payslip or bank?
Benefits, local fees, progressive detail and rounding differ by payroll vendor and lender products.
Do you store my numbers?
Core calculations run in the browser without requiring an account.
How do you avoid thin spam pages?
Each URL is a distinct intent with unique title, inputs, examples and FAQ — no city template farms.
Can I use this on mobile?
Yes. Static pages are built for fast mobile use.
Who maintains the content?
Calcly Ireland financial content team with YMYL review and visible update dates.
Which currency is used?
Default money formatting uses EUR.
Where do tax rates come from?
Shipped in params.ts for Ireland: social 0.04, VAT/GST 0.23, 2 brackets.
How should I verify this result?
May differ from payslip: USC, PRSI and tax credits vary. Cross-check with Ireland authority notes: Revenue — PAYE simplified; USC bands collapsed.. Educational only.
What to calculate next
Sources & limits
Educational model for Ireland. Revenue — PAYE simplified; USC bands collapsed. Not a substitute for payroll software or bank underwriting.