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You will get Custom Financial Calculator — Tax, Payroll, ROI & More | HTML/JS + Excel
Project details
Do you have a formula, a spreadsheet, or just an idea? I turn it into a clean, interactive calculator — web-ready, embeddable, and built with the logic actually correct.
I'm a CPA (Contadora Pública) with 10 years of experience in financial control, tax compliance, and payroll. I don't just code inputs and outputs — I understand the numbers behind them.
Proof: my Chilean income tax calculator predicted exactly $67,223 CLP in refund for a real taxpayer. The SII (Chile's tax authority) authorized exactly $67,223. Peso by peso.
Types of calculators I build:
· Financial: ROI, break-even, profit margin, cash flow, savings
· Tax & Payroll: income tax, net salary, withholding, deductions
· Loan & Real Estate: mortgage, amortization, monthly payment
· Business & Pricing: quote builder, cost estimator, markup, SaaS pricing
· Excel to Web: already have a spreadsheet? I convert it to an interactive web calculator
Every formula has a source. Every result is verifiable. Message me before ordering — if you can describe the logic, I can build it.
I'm a CPA (Contadora Pública) with 10 years of experience in financial control, tax compliance, and payroll. I don't just code inputs and outputs — I understand the numbers behind them.
Proof: my Chilean income tax calculator predicted exactly $67,223 CLP in refund for a real taxpayer. The SII (Chile's tax authority) authorized exactly $67,223. Peso by peso.
Types of calculators I build:
· Financial: ROI, break-even, profit margin, cash flow, savings
· Tax & Payroll: income tax, net salary, withholding, deductions
· Loan & Real Estate: mortgage, amortization, monthly payment
· Business & Pricing: quote builder, cost estimator, markup, SaaS pricing
· Excel to Web: already have a spreadsheet? I convert it to an interactive web calculator
Every formula has a source. Every result is verifiable. Message me before ordering — if you can describe the logic, I can build it.
Programming Languages
HTML & CSS, JavaScript, PythonCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, DesignWhat's included
| Service Tiers |
Starter
$75
|
Standard
$150
|
Advanced
$250
|
|---|---|---|---|
| Delivery Time | 3 days | 5 days | 7 days |
Number of Revisions | 1 | 2 | 3 |
Number of Pages | 1 | 1 | 2 |
Design Customization | - | ||
Content Upload | - | - | |
Responsive Design | |||
Source Code |
Optional add-ons
You can add these on the next page.
Fast Delivery
+$25 - $35
Additional Revision
+$15Frequently asked questions
About Isamar
Payroll & Tax Logic Specialist | LatAm Compliance | Excel Calculators
Vina del Mar, Chile - 12:17 pm local time
✅ I turn complex labor & tax law into accurate, auditable calculations
✅ Built a tax simulator that matches official government results, exactly
✅ Building payroll logic for across LatAm
What I do:
I design payroll, severance, and tax calculators that are grounded in actual law-labor codes, official rulings, and government tax tables, not guesswork or copied formulas.
Most calculation tools on the market get the details wrong: outdated rates, incorrect legal bases, missing edge cases. I find those errors and make sure your numbers are correct, traceable, and ready to be trusted.
My work is built so your team can audit and replicate it. Every calculation step is visible and documented with its legal source - whether you need it as an Excel tool or as logic for a web application.
How I can help you:
- Custom payroll & severance calculators (Excel / Google Sheets)
-Tax calculation engines validated against official sources
-Legal logic translated into clear, replicable formulas for your dev team
-Financial reports, KPI dashboards, and bookkeeping
-Data analysis & automation (Excel, Power Query, Power BI)
I work 100% remotely, learn new tax and labor systems quickly, and document everything so you always know where each number comes from.
If you work with payroll or tax compliance in any Latin American country and you need it done right, send me a message. I'd be glad to help.
Steps for completing your project
After purchasing the project, send requirements so Isamar can start the project.
Delivery time starts when Isamar receives requirements from you.
Isamar works on your project following the steps below.
Revisions may occur after the delivery date.
Requirements & formula review
You share your formula, spreadsheet, or idea. I confirm scope, inputs, outputs, and logic before starting no surprises.
Build & formula validation
I code the calculator and validate every formula against real data or official sources. Logic is verified before delivery.