name: property-calc
description: Thai NPA property financial calculator. Computes acquisition costs (transfer fee, SBT, WHT, stamp duty), rental yield, price per sqm/wah/rai, and break-even timeline. Use when evaluating any property's financials.
Property Financial Calculator
Overview
Calculates all financial metrics for Thai NPA property evaluation. Handles Thai-specific transfer taxes, size unit conversions (rai/ngan/wah/sqm), and rental yield analysis.
Usage
Full Analysis with Rent Range (recommended)
# Always use LOW/MID/HIGH rent scenarios instead of single rent estimate
python scripts/calc.py --price 1800000 --appraised 2500000 --sqm 35 \
--rent-low 9000 --rent-mid 10000 --rent-high 12000 \
--market-price 62800 --renovation 100000
Full Analysis (single rent)
python scripts/calc.py --price 2500000 --appraised 3500000 --rent 15000 --sqm 35
python scripts/calc.py --price 5000000 --appraised 8000000 --rai 0 --ngan 1 --wah 50 --rent 25000 --renovation 500000
Condo Example
python scripts/calc.py --price 1800000 --appraised 2500000 --sqm 28 --rent 12000 --common-fee 2000
Land Example
python scripts/calc.py --price 10000000 --appraised 15000000 --rai 2 --ngan 1 --wah 0
JSON output (for programmatic use)
python scripts/calc.py --price 2500000 --sqm 35 --rent 15000 --json
LED Auction Round Analysis
# Show price reduction schedule for round 6
python scripts/calc.py --led-round 6 --led-appraised 2600000
# LED analysis + full financial analysis combined
python scripts/calc.py --price 1820000 --appraised 2600000 --led-round 6 --sqm 143.5 --rent 15000
# JSON output of LED analysis
python scripts/calc.py --led-round 3 --led-appraised 5000000 --json
LED Auction Price Reduction Rules (กรมบังคับคดี)
| นัด (Round) |
Starting Price |
Notes |
| 1st |
100% of appraised value |
Full price |
| 2nd |
90% |
-10% if unsold |
| 3rd |
80% |
-20% if unsold |
| 4th+ |
70% (floor) |
Won't go lower |
Key points:
- Floor is 70% — price never drops below this regardless of how many rounds fail
- All 6th-round Bangkok NPA condos are already at the floor
- If a property is at floor and still unsold after 6 rounds, the issue is the property itself, not the price
Parameters
| Param |
Description |
--price |
Purchase/auction price in baht (required) |
--appraised |
Appraised value in baht (defaults to purchase price) |
--rent |
Expected monthly rent in baht |
--sqm |
Size in square meters (for condos) |
--rai |
Size in rai |
--ngan |
Size in ngan |
--wah |
Size in square wah |
--renovation |
Estimated renovation cost in baht |
--vacancy |
Vacancy rate (default: 0.10 = 10%) |
--common-fee |
Monthly common area fee in baht |
--held-over-5y |
Flag if held >5 years (0.5% stamp duty instead of 3.3% SBT) |
--led-round |
LED auction round number (shows price reduction analysis) |
--led-appraised |
Appraised price for LED analysis (defaults to --appraised) |
--rent-low |
Low rent estimate (baht/month) — use with --rent-mid and --rent-high |
--rent-mid |
Mid rent estimate (baht/month) |
--rent-high |
High rent estimate (baht/month) |
--market-price |
Market price per sqm or wah (for discount sanity check) |
--market-unit |
Unit for --market-price: "sqm" (default) or "wah" |
Thai Transfer Tax Rates
| Tax |
Rate |
When |
| Transfer Fee |
2% |
Always (on appraised value) |
| Specific Business Tax (SBT) |
3.3% |
Property held < 5 years |
| Stamp Duty |
0.5% |
Property held >= 5 years (replaces SBT) |
| Withholding Tax (WHT) |
1% |
Always |
NPA auction note: Buyer typically pays transfer fee (2%). SBT/WHT is usually seller's responsibility but varies by auction terms.
Size Conversions
| Unit |
Square Meters |
| 1 rai |
1,600 sqm |
| 1 ngan |
400 sqm |
| 1 square wah |
4 sqm |
By