“Savvy Spender” Documentation

Savvy Spender — How the Calculators Work

Introduction

Understanding your installment and loan options is key to making smart financial decisions. Savvy Spender supports three types of calculations commonly used in the Philippines:

  1. Balance Conversion — Compare bank installment vs. 0% merchant installment when you buy something with a credit card.
  2. Credit-to-Cash — Calculate how much you'll pay when converting available credit into cash.
  3. Personal Loan — Estimate payments for a bank personal loan including Documentary Stamp Tax (DST).

All calculations use the add-on (flat) rate method, which is the standard used by Philippine banks for credit card installments and most unsecured personal loans.


How Add-On (Flat) Interest Works

Philippine banks charge interest on the original principal for the entire term — not on the declining balance. This is called the "add-on" or "flat" method.

This is simpler to compute, but the Effective Interest Rate (EIR) is roughly 1.8×–2.0× higher than the stated add-on rate.

BSP Regulation: The Bangko Sentral ng Pilipinas caps the monthly add-on rate for credit card installment loans at 1.00% per month (BSP Circular No. 1098, retained by Circular No. 1165).


Calculator 1: Balance Conversion

This is for when you buy something with your credit card and want to compare your options:

Key Input Parameters

Step-by-Step Example

Input: ₱30,000 item, 1% monthly rate, 12 months, no processing fee.

Step 1 — Simple Interest: Simple Interest = ₱30,000 × 0.01 × 12 = ₱3,600

Step 2 — Factor Rate: Factor Rate = (1 + 3,600 / 30,000) / 12 = 0.0933

Step 3 — Monthly Payment: Monthly Payment = (₱30,000 + ₱3,600) / 12 = ₱2,800

Step 4 — Effective Interest Rate PA (EIR PA): Using the Excel RATE function: EIR PA = ~21.46%

Step 5 — Total Payment: Total Payment = ₱30,000 + ₱3,600 + ₱0 (processing fee) = ₱33,600

Optimal Principal Insight

If you provide a 0% installment amount, the calculator uses binary search to find the ideal principal where the bank's total installment (with interest) stays just under the 0% plan total. This helps you decide: should I take the bank conversion or the 0% merchant plan?


Calculator 2: Credit-to-Cash

Credit-to-Cash (also called Cash2Go, CashLite, Ready Cash, YourCash depending on the bank) converts your available credit limit into actual cash deposited to your bank account.

How It Differs from Balance Conversion

| Feature | Balance Conversion | Credit-to-Cash | |---------|-------------------|----------------| | Source | Existing purchases already on card | Unused available credit limit | | Output | Balance restructured into installments | Cash deposited to your account | | Use case | Managing a large purchase | Emergency cash, paying bills |

Calculation

The math is identical to Balance Conversion (add-on/flat rate). The only difference is context — you're converting unused credit to cash rather than restructuring a purchase.

Typical Fees


Calculator 3: Personal Loan

Personal loans are standalone, unsecured bank loans — separate from credit cards.

Key Difference: Documentary Stamp Tax (DST)

Personal loans above ₱250,000 are subject to Documentary Stamp Tax under the Philippine NIRC:

Example

Input: ₱500,000 loan, 1.25% monthly rate, 36 months, ₱1,500 origination fee.

You borrow ₱500K but only receive ₱494,750 — yet you pay interest on the full ₱500K.

Typical Personal Loan Rates (PH Banks)

| Bank | Monthly Add-On Rate | Approx. EIR (Annual) | Terms | |------|--------------------|--------------------|-------| | BDO | 1.39%–1.79% | 18%–24% | 6–36 months | | BPI | ~1.20% | 25%–29% | 12–36 months | | Metrobank | ~1.25% | 30%–33% | 12–36 months |


Understanding the Results

Simple Interest (%)

Total interest as a percentage of the principal. Formula: (Principal × Rate × Months) / Principal × 100.

Factor Rate

The multiplier that converts 1 unit of principal into the per-period payment. Formula: (1 + Simple Interest %) / Months.

Effective Interest Rate PA (EIR PA)

The true annualized cost of borrowing, accounting for the declining balance effect. Calculated using the Excel RATE function internally. This is always significantly higher than the stated add-on rate.

Monthly Budget Highlighting

If you provide a monthly budget, plans where the monthly payment fits within your budget appear in green. Plans that exceed your budget appear in red.


Disclaimer

Different banks may offer varying conversion terms, rates, and promos. The information provided here is for reference purposes only. Rates shown are add-on (flat) rates — the effective interest rate (EIR) will always be higher. Always verify details directly with the respective banks before making financial decisions.