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🇯🇵 在来軸組工法 (traditional post-and-beam)

House Construction Cost Breakdown for Japan (在来軸組工法)

See the real 総額, not just the housemaker's 坪単価 headline number.

Search for a Japan house cost simulator and you'll mostly find one of two things: a housemaker's own 資金シミュレーション (funding calculator, built to sell you their contract), or a lead-gen site that collects your details and forwards them to competing builders for quotes. Neither gives you an itemized takeoff you control yourself.

This tool is built for the 工務店/設計事務所 segment — buyers working with a local builder or architect on an itemized basis, not a packaged ¥/tsubo housemaker contract. It uses 建築数量積算基準 (2023 edition) 工種 trade-section categories, and splits every line into Japan's real three-bucket structure: 本体工事費 (main building), 付帯工事費 (ancillary works like 地盤改良), and 諸費用 (fees) — because budget overruns here happen almost entirely when buyers plan against 本体価格 alone.

One real, disclosed gap: no independently verifiable per-㎡ 在来軸組工法 timber coefficient exists publicly the way board-feet data does for US framing, so this tool's framing quantities reuse a cross-market timber-framing rate already verified for Australia and New Zealand — stated directly here, not hidden in a footnote.

What's in a Japan BOQ from this generator

  • 地盤調査 (soil test) and conditional 地盤改良 (soil improvement)
  • ベタ基礎 (raft foundation) and 仮設足場 (scaffolding)
  • 木工事 (在来軸組工法 timber framing) and 屋根工事 (roof covering)
  • 防水工事, 建具工事 (waterproofing, windows & doors)
  • 内装工事, 塗装工事, タイル工事 (interior, paint, tile)
  • ユニットバス and システムキッチン
  • 電気設備工事, 給排水衛生設備工事, 空調換気設備工事
  • 外構工事 (exterior works)
  • 設計監理料 (design + supervision fee), 車庫 (garage, if selected)
CurrencyJPY
Construction System在来軸組工法 (traditional post-and-beam)
BOQ Standard建築数量積算基準 (2023 edition) 工種 trade sections
PricingYour own local rates — free

Japan Bill of Quantities — Frequently Asked Questions

Is this the same as a housemaker's 坪単価 quote?
No — a housemaker quote is one bundled price for design, materials and labor together. This generator itemizes real quantities across Japan's own 工種 trade sections and shows the 総額 split into 本体工事費/付帯工事費/諸費用, which most 坪単価 headline numbers hide.
Does this tool use tsubo as an input?
Not yet — you enter square metres or square feet. A 坪単価 comparison using both 施工面積 and 延床面積 denominators (the exact trick some housemakers use to make their number look lower) is a real, named follow-up, not built yet.
What is 地盤改良 and why is it a separate line item?
Real soil-improvement work needed only if your 地盤調査 (soil test) requires it — a genuine ¥0-2,000,000 swing, and this market's own most commonly cited cost surprise. You can mark it not-applicable if your site test doesn't call for it.
Is this built for multi-builder comparison services?
No — this generates your own itemized quantities you price yourself, rather than collecting your details to forward to competing housemakers. It's for the 工務店/設計事務所 segment specifically.
🇯🇵

Generate a real Japan BOQ, free

Real quantities calculated from your project's size and construction system — you price every line with your own JPY rates. No fabricated national average, no fake accuracy claim.

Free to start · No credit card required

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