There isn't any such thing as a "typical" Tokyo apartment. You'll see them in all types of shapes, amenities will vary, flooring will be wood in some and laminate in others.
Still it helps to get a feel for what your living situation in Japan might be like by seeing some pictures, prices and layouts of "typical" Tokyo apartments. Apartment-wise, everything in Japan is talked about in terms of abbreviations. Words like loft or flat aren't used, instead you'll see abbreviations like 2DK etc. (Just scroll down for a glossary of terms like tatami mats.
Let's start with the smallest and work are way up. 1Ks and 1DKs are typically what large English schools provide for their teachers. Some schools subsidize rent others don't. Every school and situation is different.
So a 1k is a single room with a kitchen and usually a bath. 20 square meters is a typical size - about 13 jo or tatami. So a 1DK will have an eat-in kitchen or at least enough space to put a small table right off the kitchen with an additional room for sleeping. Typical sizes in meters for a 1dk is 23 - about 15.5 jo. This is the equivelent of a 1 bedroom apartment in most western countries except a bit smaller.
More Japanese apartment info. here.
Price wise, there's quite a bit of swing in Tokyo apartment prices. You can find them as cheap as 39,000 yen and as high as 125,000 yen. Get a better understanding of what you may be spending with this currency converter.
Although ESL schools typically don't put teachers in 2Ks and 2DKs if you decide to try rooming with someone you'll definitely need more space than what a 1K typically provides. Here's what to expect in a 2K and 2DK.
2DKs on average will run around 60,000 to 80,000 yen and will have 4 rooms (including the bathroom and kitchen). If you look around you can find cheaper Tokyo apartments. You definitely can find more expensive ones. 2Ks are a bit cheaper than 2DKs. A 2DK will have two bedrooms in addition to the kitchen, bathroom and dining area and a 2K won't have the dining area.
As you might have expected size has everything to do with rental prices. Surprisingly enough, an apartment that is a mere 1 or 2 tatmi size bigger can bring an extra $100 dollars in rent in no time. So, watching square meters or tatami size is important when you choose a Tokyo apartment.
Getting cheaper apartments (within reason) is important because the key money you have to pay to the landlord is based on the rent. So for example, some Tokyo apartment's key money is 4 months rent while others are only 2 or 3. So the higher your rent, the more you're going to get whacked in key money to move in.
K is the abbreviation for kitchen. Flooring in the kitchen is usually laminate, wood or tile. If the kitchen is separated from the sleeping/sitting room by a door, it is often tatami.
DK means “dining / kitchen."
L means "living" . A 1LDK will have an eat in kitchen, a room usually immediately adjacent to the eat-in kitchen which is the living room and a separate bedroom. Sizes can swing alot on these. Some are as small as 35 square meters (52 jo) up to 60 square meters or 85 jo.
GH means guest house. These are usually temporary living conditions. They can be shared or private accommodations.
Convenience, Convenience, Convenience
You may think that the AGE of the building impacts the rent but this isn't so true in Japan. The biggest factor is PROXIMITY to the train station and other surrounding amenities like parks and convenience stores etc. This is what really drives rental prices. So the closer your Tokyo aparment is to the station the more you pay even if it's old.
Tokyo Apartments and Understanding the Lingo
Here are some terms you’ll run into while looking for Tokyo apartments:
Jo or tatami
Interior sizes are measured by the size of a reed mat called a “tatami” A single tatami is 1.8 meters by 90 cm. This doesn’t mean your floors will necessarily be tatami, it’s just a system of measurement so even if your room is carpeted; it’s still measured in tatami mats. (Notice in some of the pictures of Tokyo apartments that the floors are wood).
A typical sitting room in a Japanese apartment is 6 jo which is roughly 9 square meters. This is enough room for a television, coffee table and love seat. A noteworthy fact about tatami measurements is that they're not standard. Often you'll find newer apartments quoted as 6 tatami, but the mat's size is smaller than the tatami mat sizes you'll find in older apartments.
Simply means a concrete or metal-framed apartment house of typical size found in Japan. Don’t expect them to be anything like the name implies.