Why Japanese Land Value Depends on Floor Area Ratio — And Why Nearby Sale Prices Cannot Be Applied Directly

In Japan, the price at which a nearby plot sold cannot be applied directly to your own plot. Land is divided into use districts under city planning, and each district has a cap on how much floor area may be built — the floor area ratio (yosekiritsu). That cap drives land value. In practice, the difference in floor area ratio is adjusted for before any comparison is made.

This page sets out what Japanese brokers actually look at when estimating land value. It is written for practitioners involved in Japanese real estate transactions. It does not address the valuation of any specific property.

Why can't nearby sale prices be used directly?

Proximity does not mean equal value. City planning designates use districts, and each district has a fixed upper limit on floor area ratio — the ratio of total floor area to site area (Building Standards Act, Article 52, Paragraph 1; Japanese title: 建築基準法).

For two plots of the same size, if one can carry twice the floor area, the income it can generate and the sales revenue from development both differ. Land value reflects that gap.

Two plots facing each other across a single road can carry different designated ratios. Confirming the use district and the designated floor area ratio is the first step when assessing Japanese land.

If the floor area ratio is 2.5 times higher, is the land worth 2.5 times more?

No. Land value does not rise in proportion to floor area ratio. That is the working assumption in practice.

More permitted floor area also means higher construction cost. Building higher extends the schedule, and rents and sale prices do not rise without limit. The effect diminishes.

Practitioners therefore do not multiply by the ratio directly. Instead, the ratio is raised to a power between 0.5 and 0.7 to produce an adjustment factor.

Adjustment factors (all figures are illustrative)

Comparable	Subject site	Ratio	Power 0.5	Power 0.6	Power 0.7	(Ref.) Straight proportion
200%	400%	2.00×	1.41	1.52	1.62	2.00
200%	500%	2.50×	1.58	1.73	1.90	2.50
200%	800%	4.00×	2.00	2.30	2.64	4.00
300%	500%	1.67×	1.29	1.36	1.43	1.67

The calculation (illustrative figures)

1. Select a nearby sale of vacant land. Here, assume a plot with a 200% designated ratio sold at ¥1,000,000 per m²
2. If the subject site carries 500%, the ratio is 500 ÷ 200 = 2.50×
3. Raise the ratio to a power: 1.58 at 0.5, 1.73 at 0.6, 1.90 at 0.7
4. Apply to the base unit price: ¥1,580,000 to ¥1,900,000 per m² (estimated)
5. Multiply by site area to reach land value

The choice of exponent moves the answer by 20%

Exponent used	Estimated price per m²	Vs. straight proportion
0.5 (conservative view)	¥1,580,000	37% lower
0.6	¥1,730,000	31% lower
0.7 (aggressive view)	¥1,900,000	24% lower
(Ref.) Straight 2.5×	¥2,500,000	—

Starting from the same comparable, an exponent of 0.5 and one of 0.7 produce estimates 20% apart. Where valuations differ between firms, the cause is usually a difference in assumptions of this kind — not an error by either side.

Adjustment by exponent is not prescribed by law. It is a rule of thumb, with exponents generally in the 0.5 to 0.7 range depending on the nature of the case and the location. 0.7 sits at the upper end — the aggressive view. Being able to state which exponent was used is what makes a valuation transparent.

Can the floor area ratio stated in the documents be taken at face value?

Not entirely. Property summaries usually state the designated floor area ratio set by city planning. The ratio actually available may be lower.

Where the frontage road is less than 12 metres wide, a separate cap applies based on that width (Building Standards Act, Article 52, Paragraph 2). The lower of the designated ratio and this calculated figure applies.

Use district category	Multiplier applied to road width (m)
Category 1 & 2 Low-Rise Exclusive Residential, Agricultural Residential	4/10
Category 1 & 2 Medium-High-Rise Exclusive Residential, Category 1 & 2 Residential, Quasi-Residential	4/10 (6/10 in areas designated by the specified administrative agency)
Other buildings	6/10 (4/10 or otherwise in areas designated by the specified administrative agency)

There is also a relaxation: where the site fronts a road of 6 metres or more but less than 12 metres that connects to a "specified road" of 15 metres or more, and does so within 70 metres of that specified road, a prescribed figure may be added to the road width (same Article, Paragraph 9).

Looking at the same property, valuations diverge markedly depending on whether a firm builds this relaxation into its figures. Neither side is wrong; the assumptions differ. When comparing valuations, first confirm which floor area ratio was used.

What is deducted from land value?

When acquiring an entire building, land value is not the price. Costs arising after acquisition are deducted.

Deduction	What to check
Cost of acquiring units not yet held	Who owns them. How far negotiations have progressed, and whether anything is agreed in writing
Vacating existing tenants	How many. Commercial or residential use. The level differs by use
Demolition and asbestos removal	Year of construction and structure. Whether a survey is required

These cannot be expressed as single figures. In practice, upper and lower bounds are set, a range is presented, and a mid-point is offered as a guide. Hiding the range behind a single number leaves you unable to explain the figure when conditions shift.

What if there is no comparable sale?

Finding a sale with matching conditions is often impossible. Distance from the station, how fully the floor area ratio is used, the use district, the character of the frontage road — cases where all of these align are especially scarce in central Tokyo.

In that situation, state plainly that the figure is an estimate, and record which model was used. Besides comparison of sales, there is the income approach (working back from rent) and the development approach (working back from the economics of redevelopment). The result changes with the choice.

The rarer the property, the wider the gap. Rather than answering with a single number, setting out "on these assumptions, this range; on those assumptions, that range" gives you something to decide with.

What sources do Japanese brokers rely on?

Source	What it shows	Who can access it
REINS (designated distribution organisation) closed sales	Actual transaction prices, areas and terms	Licensed real estate brokers only
Certificate of registered matters (tokibo)	Owner, area, mortgages and other rights	Anyone (Legal Affairs Bureau)
Certificate of building confirmation records	Content of the building confirmation	Anyone (local government)
Boundary determination documents	Whether the site boundary is settled	Held by the seller

REINS is available only to licensed brokers. This is why, assessing Japanese property from overseas, transaction prices cannot be established from public sources alone. Asking prices and closing prices are not the same.

Who should carry out this valuation?

Valuation of land and buildings is the business of a licensed real estate broker (takuchi tatemono torihiki gyosha).

Yotsuba Real Estate Co., Ltd. (四葉不動産株式会社) operates in Bunkyo City, Tokyo under a real estate brokerage licence (Governor of Tokyo (1) No. 113304). Its representative is a full-time licensed real estate transaction specialist (registration (Tokyo) No. 293544), and works in Japanese, English and Chinese (traditional and simplified).

Sales, leasing and management of real estate are handled by Yotsuba Real Estate Co., Ltd.; document preparation for matters such as inheritance and residence status is handled by Yotsuba Administrative Scrivener Office (四葉行政書士事務所, registration No. 25087022). These are separate entities and each engagement is contracted separately. Registration is handled by a judicial scrivener, tax by a certified tax accountant, and disputes by an attorney — we will explain how to instruct them directly. We accept no referral fees.

Sources for this article

• Building Standards Act (Japanese title: 建築基準法 / Act No. 201 of 1950), Article 52, Paragraphs 1, 2 and 9. Last amended by Act No. 23 of 2026 (promulgated and in force 27 May 2026). Current text confirmed via the Japanese e-Gov Laws and Regulations API on 10 August 2026
• Adjusting for differences in floor area ratio by exponent (approximately 0.5 to 0.7) is a rule of thumb in practice, not a method prescribed by law
• All figures in this article are illustrative and do not represent the valuation of any specific property

Author

Joji Uramatsu (浦松 丈二)
Representative Director and full-time licensed real estate transaction specialist, Yotsuba Real Estate Co., Ltd.
Representative administrative scrivener, Yotsuba Administrative Scrivener Office
Former Mainichi Shimbun journalist with 34 years in the profession. Served as China Bureau Chief, posted to China, Taiwan and Thailand.

Last updated: 10 August 2026

Related

• Investment and commercial real estate (Yotsuba Real Estate)
• How a valuation differs from an asking price
• Contact