This guide is only for identifying your Steinway model and size; once confirmed, use the ordering page for cover options.
Article Summary:
- Grand: Find the model letter on the cast-iron plate (A, B, D, etc.), then measure overall length and cross-check it against the model size category.
- Serial number: Useful for identity/year reference, not for determining the model letter.
- Upright: Model naming can be inconsistent—fit is typically driven by height/width/depth plus a few cabinet notes.
- If anything is unclear (faint stamp, Model A, L vs O), measurement is the tie-breaker.
Intro
Most Steinway owners can answer “Is it a Steinway?” quickly. The hard part is the next question: which model is it, and what size category does it fall into? That matters any time you need a properly fitting cover—especially when the fit depends on the exact model and length. This guide shows a practical workflow: find the model letter (when it exists), record the serial number for reference, and verify size by measurement.
Quick answer (60 seconds)
Find the model Letter (A, B, M, L, O, S, D) located on the inside of your Steinway grand piano on the cast-iron plate. If you cannot find a model letter, you can measure the overall length of your piano (including the piano keys). Take the length measurement and refer to the sizing chart, which should tell you the model of your piano. Note that there are two issues here. First, the model L and O are both 5'10.5". They differ in tail shape (square vs round). Second, the Steinway model A has come in three different sizes, and the 6'1.5" size came in two different tail shapes (square vs round).
With regards to the tail shape for the L, O, and A models. The round shape is like a semi circle, whereas the square tail shape is curved on the sides then flat across the back of the tail (so it does not have square, 90 degree edges--they are curved). Pictures are provided with examples further down the page.
If you want the bigger picture on measuring, selecting materials, and choosing options (after you’ve confirmed your model/size), see our piano cover purchasing guide.
Serial number vs model letter (don’t mix these up)
What the serial number tells you
The serial number is an identity and reference number. It’s commonly used to estimate the manufacturing year using Steinway serial number lists, and it’s useful for documentation (service records, insurance, resale paperwork).
What the serial number does not tell you (the model letter)
The serial number does not reliably tell you the model of the piano--it only tells you the year it was made. Two pianos with similar serial numbers can be different models. For identification and sizing, you need the model letter (when available) and/or measurements.
Keep it simple:
- Serial number = identity/year reference
- Model letter + measurement = model/size confirmation
Steinway grand pianos — where to find the model letter
Location: the cast-iron plate stamp (model letter)
On modern Steinway grands, the model is indicated by a single letter stamped into the cast-iron plate (the gold frame inside the piano). A common place to look is the front plate area above the keys/fallboard. You will see a letter (S, M, O, L, A, B, C, or D) followed by the serial number. Please see below the example of a Steinway model B letter location.
Steinway grand model list and lengths (S/M/L/O/A/B/C/D)
Quick reference table (model → typical length category)
If you cannot find a model letter, you may also be able to identify your Steinway by its total length (measured from the very front of the keyboard to the tip of the tail). Exact lengths can vary by era and design details. Please use the below table to see the length of each Steinway model. If your piano measures 5'7" for example, you know you have a model M.
| Steinway Grand Model | Typical length category |
|---|---|
| S | 5'1" |
| M | 5'7" |
| L | 5'10" (often described as “square tail”) |
| O | 5'10" (often described as “round tail”) |
| A | 6'0", 6.1'5", 6'4.5" (varies; verify by measurement) |
| B | 6'11" |
| C | 7'5" |
| D |
9'0" |
How to measure grand piano length accurately (the endpoints that matter)
Measure the full case length--including the piano keys, not just the lid. You want the longest measurement possible.
Once you’ve confirmed your model letter and length category, the ordering page is the place to choose the correct model/size option: Steinway ordering page.
Common confusion: Model L vs Model O
Why it matters for a made-to-fit selection
The Steinway models L and O are both 5'10.5". They have different shapes, however. The Steinway O has a round tail, and the Steinway L has more of a square tail shape. Therefore in this scenario, just knowing the 5'10.5" length of your piano will not be enough, and you will need to find the model letter stamped inside the piano, or identify it based on the tail shpae.
Model A requires extra verification
Why Model A varies
The Steinway Model A has come in 3 different sizes over its production lifespan. The model that measures 6'1.5" has two different tail shapes--round and square. The round tail is like a semi-circle. The square tail is curved on the sides, while being straight across (so it's not actually a square, as the sides are rounded).
How to verify which “A” you have (step-by-step)
- Confirm the stamp reads A.
- Measure full case length using the endpoints above, to determine which model A you have.
- If you have the 6'1.5" version, determine if you have a round or square tail shape.
Below are example of the round tail shape vs the square tail shape design by Steinway:
Pictured Above: Steinway Model A with Round Tail
Steinway Model A with Square Tail Shape
How to find the model on a Steinway upright piano
Where to look (inside top lid, fallboard, back frame, labels)
Identifying the model of an upright piano is often more difficult. Upright model naming can be inconsistent across eras, and some markings are simply not easy to locate. If you have an older Steinway, it may only have a serial number, and not a model number. The serial number will only tell you the year the piano was manufactured.
Places to look for the model on a Steinway upright piano:
- Inside the top lid (if it opens)
- Behind/under the fallboard (key cover area)
- On the back of the cabinet/frame (labels are sometimes present)
- Record the serial number wherever you find it
What information to record for an upright
For uprights, fit is typically driven by measurements.
Measure and record
- Height: floor to top of cabinet
- Width: widest point left to right
- Depth: deepest point front to back (include any key-slip protrusion)
Pictured is the Steinway model K52 plate, with the serial number 503851
Next step
Once you’ve confirmed the model letter (if available) and cross-checked the measurements, you’re ready to choose options on the ordering page. If you want a broader overview of measuring and selecting options across different pianos, the purchasing guide linked earlier is the best starting point.
FAQs
Where is the model letter on a Steinway grand?
It’s typically stamped on the cast-iron plate, often near the front area above the keys/fallboard. Look for a single letter marking (e.g., A, B, D) that indicates the grand model.
Where is the serial number located on a Steinway?
On many Steinway grands, the serial number is found on the plate and/or other fixed components. It’s used to identify the instrument’s production sequence and is commonly referenced to determine the manufacturing year.
Does the serial number tell the model?
No. The serial number is primarily used to identify the piano and its production year; the model is determined by the model letter and confirmed by length.
How do I tell Steinway Model L vs Model O?
Start with the plate stamp (model letter), then confirm with length. Because L and O can be confused visually, use measurement as the tie-breaker rather than relying on appearance alone.
Why does the Steinway Model A require extra verification?
The Steinway model A has come in three different sizes and two different tail shapes over the last 100+ years. That’s why you should always confirm a Model A by measuring length and matching it to the correct size category.
How do I identify a Steinway upright model or cabinet type?
Uprights often require a combination of measurements (height/width/depth) and any interior markings or labels under the top lid or inside the case. If a specific model name isn’t clear, measurements are the most dependable input for fit.
What if I can’t find the plate stamp on my grand?
If you cannot find the model of your Steinway, you will need to measure the overall length of the piano. That can help determine the model.
