# Architect Calculator > Seven Python-based architectural calculators for common design computations: area and density calculations (GFA, NGA, unit count, population, parking), thermal U-value analysis for multi-layer constructions, daylight factor estimation using BRE methodology, egress compliance checking (occupant load, exit width, travel distance), structural gravity load and tributary area calculations, annual energy demand estimation via degree-day method, and construction cost estimation by building type, quality, and region. - Skill: `abhinavbwj/architect-calculator` (Agent Skill, multi-file: 9 files) - Install (CLI): `npx skillmds@latest add abhinavbwj/architect-calculator` - Raw SKILL.md: https://api.skillmd.com/api/skills/abhinavbwj/architect-calculator/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: abhinavbwj (https://skillmd.com/u/abhinavbwj) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/abhinavbwj/architect-calculator --- # Architect Calculator A suite of seven command-line Python calculators for rapid architectural design computations. Each calculator accepts parameters via command-line arguments, validates inputs, and produces either human-readable or JSON-structured output. All scripts are located in the `scripts/` directory and can be run with: ``` python scripts/.py [arguments] ``` Add `--json` to any command for structured JSON output suitable for piping into other tools or automation workflows. --- ## 1. Area Calculator (`area_calculator.py`) Calculates development density metrics from site area and floor area ratio (FAR), including gross floor area, net usable area, residential unit count, estimated population, and parking requirement. ### Parameters | Parameter | Flag | Default | Unit | Description | |--------------------|--------------------|---------|--------|--------------------------------------| | Site Area | `--site-area` | Required| m2 | Total site/plot area | | Floor Area Ratio | `--far` | Required| ratio | Permitted FAR / plot ratio | | Net-to-Gross Ratio | `--ntg-ratio` | 0.80 | ratio | NGA as fraction of GFA (0.0-1.0) | | Avg Unit Size | `--avg-unit-size` | 85 | m2 | Average residential unit area | | Persons per Unit | `--persons-per-unit`| 2.5 | persons| Average household size | | Parking Ratio | `--parking-ratio` | 1.0 | spaces | Parking spaces per dwelling unit | ### Example ```bash python scripts/area_calculator.py --site-area 5000 --far 2.5 --ntg-ratio 0.82 ``` ### Sample Output ``` === Area & Density Calculator === Site Area: 5,000.00 m2 Floor Area Ratio: 2.50 --------------------------------------- Gross Floor Area: 12,500.00 m2 Net-to-Gross Ratio: 0.82 Net Gross Area: 10,250.00 m2 --------------------------------------- Average Unit Size: 85.00 m2 Estimated Units: 120 Persons per Unit: 2.50 Estimated Population: 300 --------------------------------------- Parking Ratio: 1.00 spaces/unit Parking Spaces: 120 ``` --- ## 2. U-Value Calculator (`uvalue_calculator.py`) Calculates the thermal transmittance (U-value) of a multi-layer wall, roof, or floor construction by summing thermal resistances of each layer plus surface resistances. ### Parameters | Parameter | Flag | Default | Unit | Description | |----------------|-------------------|---------|-------------|---------------------------------| | Layers | `--layers` | Required| JSON string | Array of layer objects | | Rsi Internal | `--rsi-internal` | 0.13 | m2K/W | Internal surface resistance | | Rsi External | `--rsi-external` | 0.04 | m2K/W | External surface resistance | Each layer object: `{"name": "...", "thickness_mm": N, "conductivity": N}` ### Example ```bash python scripts/uvalue_calculator.py --layers '[ {"name": "Brick", "thickness_mm": 102, "conductivity": 0.77}, {"name": "Cavity air gap", "thickness_mm": 50, "conductivity": 0.18}, {"name": "Mineral wool", "thickness_mm": 100, "conductivity": 0.035}, {"name": "Concrete block", "thickness_mm": 140, "conductivity": 1.13}, {"name": "Plaster", "thickness_mm": 13, "conductivity": 0.16} ]' ``` ### Sample Output ``` === U-Value Calculator === Layer Thickness(mm) Conductivity(W/mK) R-value(m2K/W) --------------------------------------------------------------------------- Rsi (internal) -- -- 0.1300 Brick 102 0.770 0.1325 Cavity air gap 50 0.180 0.2778 Mineral wool 100 0.035 2.8571 Concrete block 140 1.130 0.1239 Plaster 13 0.160 0.0813 Rse (external) -- -- 0.0400 --------------------------------------------------------------------------- Total R-value: 3.6425 m2K/W U-value: 0.2745 W/m2K Passive House target (wall): 0.15 W/m2K -- DOES NOT MEET Typical code target (wall): 0.30 W/m2K -- MEETS TARGET ``` --- ## 3. Daylight Calculator (`daylight_calculator.py`) Estimates average daylight factor for a side-lit room using the BRE simplified formula. ### Parameters | Parameter | Flag | Default | Unit | |----------------------|---------------------------|---------|-------| | Room Width | `--room-width` | Required| m | | Room Depth | `--room-depth` | Required| m | | Room Height | `--room-height` | Required| m | | Window Width | `--window-width` | Required| m | | Window Height | `--window-height` | Required| m | | Window Sill Height | `--window-sill-height` | Required| m | | Glazing Transmittance | `--glazing-transmittance` | 0.65 | ratio | | Average Reflectance | `--average-reflectance` | 0.50 | ratio | ### Example ```bash python scripts/daylight_calculator.py \ --room-width 4.0 --room-depth 6.0 --room-height 3.0 \ --window-width 2.5 --window-height 1.8 --window-sill-height 0.9 ``` ### Sample Output ``` === Daylight Factor Calculator === Room: 4.00m W x 6.00m D x 3.00m H Window: 2.50m W x 1.80m H (sill at 0.90m) --------------------------------------- Window Area: 4.50 m2 Total Room Surface Area: 96.00 m2 Window-to-Floor Ratio: 18.75% Glazing Transmittance: 0.65 Average Reflectance: 0.50 Visible Sky Angle: 60.1 deg --------------------------------------- Average Daylight Factor: 2.34% Assessment: ADEQUATE (target >= 2.0% for habitable rooms) ``` --- ## 4. Egress Calculator (`egress_calculator.py`) Calculates occupant load, required number of exits, minimum exit widths, and travel distance compliance per IBC. ### Parameters | Parameter | Flag | Default | Description | |----------------|--------------------|---------|---------------------------------| | Floor Area | `--floor-area` | Required | Net floor area in m2 | | Occupancy Type | `--occupancy-type` | Required | IBC occupancy (A-1 to U) | | Sprinklered | `--sprinklered` | False | Flag: building is sprinklered | | Num Stories | `--num-stories` | 1 | Number of stories | ### Example ```bash python scripts/egress_calculator.py --floor-area 800 --occupancy-type B --sprinklered --num-stories 4 ``` ### Sample Output ``` === Egress Calculator === Floor Area: 800.00 m2 Occupancy Type: B (Business) Sprinklered: Yes Number of Stories: 4 --------------------------------------- Occupant Load Factor: 9.3 m2/person Occupant Load: 86 persons --------------------------------------- Required Exits: 2 Min Exit Width (total): 1,376 mm Width per Exit: 688 mm Min Door Width: 813 mm (32 inches) --------------------------------------- Max Travel Distance: 91.0 m (300 ft) [sprinklered] Max Common Path: 23.0 m (75 ft) Max Dead End: 15.0 m (50 ft) COMPLIANCE: Review travel distances on plans. ``` --- ## 5. Structural Load Calculator (`structural_load_calculator.py`) Calculates tributary area gravity loads for preliminary structural sizing. ### Parameters | Parameter | Flag | Default | Unit | Description | |----------------|--------------------|---------|---------|-----------------------------| | Tributary Area | `--tributary-area` | Required| m2 | Column tributary area | | Num Floors | `--num-floors` | Required| integer | Number of supported floors | | Dead Load | `--dead-load` | 4.5 | kN/m2 | Dead load per floor | | Live Load | `--live-load` | auto | kN/m2 | Live load (auto per occ.) | | Occupancy Type | `--occupancy-type` | office | string | For auto live load selection | ### Example ```bash python scripts/structural_load_calculator.py --tributary-area 36 --num-floors 8 --occupancy-type office ``` ### Sample Output ``` === Structural Load Calculator === Tributary Area: 36.00 m2 Number of Floors: 8 --------------------------------------- Dead Load: 4.50 kN/m2 per floor Live Load: 2.50 kN/m2 per floor (office) Total per Floor: 7.00 kN/m2 --------------------------------------- Load per Floor: 252.00 kN Total Column Load: 2,016.00 kN (8 floors) Factored Load: 2,822.40 kN (1.2D + 1.6L) --------------------------------------- Preliminary Column: ~400x400 mm RC (fc'=35 MPa) ``` --- ## 6. Energy Calculator (`energy_calculator.py`) Estimates annual heating and cooling energy demand using the degree-day method. ### Parameters | Parameter | Flag | Default | Unit | Description | |--------------------|------------------------|---------|---------|-------------------------------| | Floor Area | `--floor-area` | Required| m2 | Conditioned floor area | | Envelope Area | `--envelope-area` | Required| m2 | Total envelope area | | Average U-value | `--average-u-value` | Required| W/m2K | Area-weighted average U | | Heating Degree Days | `--heating-degree-days`| Required| Kd | Annual HDD (base 18C) | | Cooling Degree Days | `--cooling-degree-days`| Required| Kd | Annual CDD (base 24C) | | Ventilation Rate | `--ventilation-rate` | 0.5 | ACH | Air changes per hour | | Internal Gains | `--internal-gains` | 5.0 | W/m2 | Internal heat gains | ### Example ```bash python scripts/energy_calculator.py \ --floor-area 500 --envelope-area 800 --average-u-value 0.35 \ --heating-degree-days 3000 --cooling-degree-days 500 ``` ### Sample Output ``` === Energy Calculator === Floor Area: 500.00 m2 Envelope Area: 800.00 m2 Average U-value: 0.35 W/m2K --------------------------------------- Heating Degree Days: 3,000 Kd Cooling Degree Days: 500 Kd Ventilation Rate: 0.50 ACH Internal Gains: 5.00 W/m2 --------------------------------------- Transmission Loss: 6,720.00 kWh/yr Ventilation Loss: 4,050.00 kWh/yr Internal Gains: -2,190.00 kWh/yr Heating Demand: 8,580.00 kWh/yr --------------------------------------- Cooling Demand: 2,356.00 kWh/yr --------------------------------------- Total Demand: 10,936.00 kWh/yr EUI: 21.87 kWh/m2/yr Passive House target: 15 kWh/m2/yr -- DOES NOT MEET ``` --- ## 7. Cost Calculator (`cost_calculator.py`) Estimates construction cost based on building type, quality level, and geographic region. ### Parameters | Parameter | Flag | Default | Description | |-----------------|---------------------|--------------|------------------------------------| | GFA | `--gfa` | Required | Gross floor area in m2 | | Building Type | `--building-type` | Required | residential/office/retail/hospital/school/hotel | | Quality | `--quality` | standard | basic/standard/premium | | Region | `--region` | north-america| north-america/europe/middle-east/asia/australia | | Include External | `--include-external`| False | Flag: include site works | ### Example ```bash python scripts/cost_calculator.py --gfa 5000 --building-type office --quality premium --region europe ``` ### Sample Output ``` === Construction Cost Calculator === Gross Floor Area: 5,000.00 m2 Building Type: Office Quality Level: Premium Region: Europe --------------------------------------- Base Cost Rate: 2,800.00 USD/m2 Construction Cost: 14,000,000 USD --------------------------------------- Professional Fees (12%): 1,680,000 USD Contingency (7.5%): 1,050,000 USD External Works: -- --------------------------------------- Total Development Cost: 16,730,000 USD Cost per m2 (total): 3,346.00 USD/m2 ``` --- ## Methodology Reference Detailed formulas and methodology for each calculator are documented in `references/calculator-reference.md`. ## Error Handling All calculators validate inputs and provide clear error messages: - Missing required parameters display usage help - Out-of-range values are rejected with explanatory messages - Invalid occupancy types list accepted values - Malformed JSON input shows expected format ## Integration JSON output (`--json` flag) enables integration with: - Other scripts in the pipeline - Spreadsheet tools (parse JSON) - Web dashboards - Automated reporting systems - BIM parameter injection