John Deere Blade Cross Reference by GX and AM Numbers
2026-10-15 · 8 min read
John Deere mower blades are identified by GX and AM part numbers stamped on the blade and the deck plate. A correct cross reference matches length, centre hole, thickness and lift type — not just the number. Use the OEM number together with your deck width to find a replacement that actually fits.
Why a John Deere blade cross reference matters
A cross reference matters because two blades with the same part number can still differ in hole pattern, thickness and lift, and the wrong one will not seat on the spindle. John Deere has used many blade numbers across 42-inch residential decks and 60-inch commercial decks, so matching by number alone leaves the fit to chance. Our guide to matching a blade by OEM number walks through reading the format before you order.
How John Deere numbers its blades
John Deere uses two main prefixes, and the prefix tells you which kind of machine the blade came from. GX numbers appear on residential riders and walk-behinds, while AM numbers cover commercial and older riders. Recognising the prefix stops you from quoting a commercial number when you actually need a homeowner blade.
| Prefix | Typical use | Example form | What it signals |
|---|---|---|---|
| GX | Residential riders, walk-behinds | GX20249 | 42–48 in homeowner decks |
| AM | Commercial, older riders, zero-turn | AM137757 | Larger decks, heavier duty |
| UC / M | Some utility and vintage lines | UC10026 | Older or regional models |
The letters are a house style, not a specification. A GX number and an AM number of the same length describe different blades, so always pair the number with the deck size.
Where to find the blade number on your mower
The number is stamped near the centre hole on the flat of the blade, but grass and rust hide it, so wire-brush the area first. If the blade is gone, the deck or model plate near the discharge chute or under the seat gives the machine model, which is enough to look the blade number up. The machine manual and the manufacturer's own parts catalogue both list the blade number by model.
Common John Deere blade numbers by series
The numbers below are examples of John Deere's public part-number styles, shown so you can recognise the format on your own blade. They are for fitment reference only — we are an independent manufacturer and not an authorised John Deere dealer.
- GX20249 — a common 21-inch walk-behind / small rider blade style.
- GX20433 — frequently seen on 42-inch residential decks.
- GX21833 — a toothed mulching-style number in the GX range.
- AM137757 — a commercial zero-turn blade style for larger decks.
- AM115809 — an older rider blade number still quoted by owners.
If your number is not in this short list, that is normal — John Deere has issued hundreds of blade numbers over the years. Send the exact stamping and your deck width and we will cross-reference it against the model index, which lists the profiles we keep for John Deere-fit decks alongside other brands.
How to cross-reference without the original number
Cross-referencing without the old number is straightforward if you record four measurements from the machine instead. Measure the old blade tip-to-tip, note the centre-hole type, check the thickness with a caliper, and say which way the blade turns. With those four facts plus the deck width, a supplier can name the right profile even when the stamping is illegible. Our blade measuring guide shows exactly what to record before you write to a supplier.
What a correct replacement must match
A replacement is correct only when every mounting and cutting dimension lines up, because a close-enough blade vibrates, cuts unevenly or fails to seat. The table below is the checklist we use before quoting any John Deere-fit blade.
| Spec | Why it matters | How to confirm |
|---|---|---|
| Overall length | Seats the spindle and clears the deck | Measure tip to tip |
| Centre hole | Mounts on the mandrel | Match hole type exactly |
| Thickness | Load rating under impact | Caliper the old blade |
| Lift type | Decides cut result | Compare blade profile |
Length and hole type cause the most fitment failures, so double-check those two before anything else.
Are all GX blades interchangeable?
No — GX blades are not interchangeable just because they share the prefix, because the suffix and the deck width determine length, hole and lift. A GX number from a 42-inch deck will not suit a 54-inch deck even when the prefix matches. Always confirm the deck size printed on the machine plate against the blade you intend to fit.
How John Deere-fit blades are made to spec
John Deere-fit blades we supply are made to match the original specifications of the OEM number you send, cut from 40Mn manganese steel and hardened to a 45–50 HRC band so the edge holds through grit yet will not crack on hidden stone. The same heat-treat control that decides working life is detailed on our quality page, which is the part of production that most affects how a blade performs under real mowing load. We are an independent manufacturer; brand names are used for fitment reference only.
Can you get custom John Deere-fit blades made to a sample?
Yes — custom John Deere-fit blades are made to a supplied sample or drawing, typically from 40Mn steel and held in the 45–50 HRC band we run across the catalogue. Share the old blade or its part number and we will confirm fitment, profile and run size. The minimum order for a custom profile is normally 300 pieces, which covers the setup and heat-treat run for a made-to-sample blade. Send your part number or a photo of the old blade to start, or browse the model index for stock shapes.
Frequently Asked Questions
Are John Deere GX blades interchangeable across models?
No — GX blades interchange only when length, centre hole, thickness and lift also match, which they rarely do across different deck sizes. A 42-inch deck blade and a 54-inch deck blade may share the GX prefix but will not fit the same mandrel. Always confirm the deck width printed on the machine plate.
What does AM mean on a John Deere blade?
AM marks John Deere's commercial and older-rider blade numbering style, used on larger decks and zero-turn machines rather than homeowner riders. An AM number such as AM137757 points to a heavier-duty blade than a typical GX number. The prefix is a house code, not a specification, so pair it with the deck size.
Can I fit a non-John Deere blade on my Deere mower?
Yes — you can fit an independent blade as long as the length, centre hole, thickness and lift match the original, because the mower cares about the geometry, not the brand on the box. We make John Deere-fit blades to match the original specifications and are an independent manufacturer, not an authorised dealer. Match the dimensions and the blade will seat and cut correctly.
How do I find my John Deere blade number if the stamping is worn?
Wire-brush the flat near the centre hole, then read the deck or model plate near the discharge chute or under the seat if the blade is unreadable. With the machine model and deck width you can look the blade number up in the manufacturer's parts catalogue. Send us those details and we will cross-reference them against our model index.
What is the minimum order for custom John Deere-fit blades?
The minimum order for a custom John Deere-fit blade is typically 300 pieces per profile, which covers the setup and heat-treat run for a made-to-sample blade. Share the part number or a drawing and we will confirm fitment and quote the run before any cutting begins. Send your specifications to get a quote sized to your machine.
Not sure which John Deere blade fits your deck, or want a custom profile made to a sample? Send us your part number or a photo of the old blade and we will confirm fitment and quote — or start from the model index.
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Blade part numbers linked to this article
The model pages below carry the deck size, centre hole, thickness and replacement numbers for the blades discussed above.