What Router Bit for Door Hinges? (Size & Radius Guide)
A 1/2-inch diameter straight or spiral up-cut router bit is the standard choice for door hinge mortises — its round profile naturally cuts a 1/4-inch corner radius, which matches most residential butt hinges. Use the wrong diameter and you get gaps or extra chisel work squaring corners. This guide covers bit sizing, radius matching, mortise depth, and using a hinge template jig.
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Best Router Bit for Door Hinge Mortises (Size Chart)
The bit you need depends on whether you’re routing freehand along marked lines or guiding a template with a bearing or guide bushing. All four options below cut a usable hinge mortise — the difference is precision and repeatability. If you’re still building out your router setup, see our broader woodworking tools and saws guide for how a router fits alongside your other shop tools, or browse our full tool guides section.
| Router Bit | Diameter / Shank | Corner Radius Produced | Best For |
|---|---|---|---|
| Straight or spiral up-cut bit | 1/2 in. dia., 1/4 in. shank | 1/4 in. radius | Standard residential butt hinges (most common setup) |
| Template-trim (bearing-guided) hinge mortising bit | 3/4 in. cutting dia., 1/4 in. shank | Matches template edge | Repeated, identical mortises with a hinge template jig |
| Compression / spiral bit | 1/2 in. dia., 1/4 in. shank | 1/4 in. radius | MDF or veneered doors, where a straight bit tears the face |
| 1/2-inch straight bit + corner chisel | 1/2 in. dia. | Square (after hand-chiseling) | Commercial or older hinges with square corners |
Match the Bit’s Corner Radius to Your Hinge
A hinge mortise is the shallow recess a router cuts into a door edge and jamb so the hinge leaf sits flush. Its corners take one of three shapes, and matching them to your bit is what most guides skip. A round 1/2-inch bit cuts a 1/4-inch radius corner by geometry — the radius always equals half the bit’s diameter.
- Square corner: Found on some older and commercial-grade hinges. Rout the mortise, then square the rounded corners with a mortising chisel.
- 1/4-inch radius corner: The most common style on residential interior and exterior door hinges. A stock 1/2-inch straight or spiral bit matches this radius with no extra squaring.
- 5/8-inch radius corner: Used on some larger or heavy-duty hinges. Needs a larger-diameter bit or a template ground to that radius — a standard 1/2-inch bit won’t match it.
📊 Most standard butt hinges use a 1/4-inch radius corner, and a 1/2-inch diameter router bit is sized specifically to produce that radius. — Source: Rockler, hinge mortising router bit specifications
Setting the Mortise Depth
Set the router’s plunge depth to match the hinge leaf’s thickness exactly — not the whole hinge, just one leaf. Standard-weight residential hinges run about 0.134 inch (roughly 1/8 inch) thick; heavy-weight and commercial hinges run closer to 0.180 inch. Cut too shallow and the door binds against the jamb; cut too deep and the hinge sits proud, leaving a visible gap along the closed edge.
Measure your specific hinge leaf with calipers before setting the bit — manufacturers vary enough that “standard weight” isn’t a guarantee. This is the same fit tolerance used in mortise and tenon joinery: the recess should match the part going into it, not an approximation.
Best Hinge Jig Pick
Crafom Aluminum Door Hinge Template Jig – $26.95
Cuts 2-1/2 to 5-inch mortises and includes both 1/4-inch and 5/8-inch radius corner guides plus a square-corner option — the exact radius-matching decision this guide walks through.
- Best for: Getting consistent mortises across multiple hinges without hand-marking each one
- Why we picked it: Covers both radius styles and square corners in one aluminum template
- Main drawback: Square-corner hinges still need a corner chisel to finish — the jig alone won’t square a router’s rounded cut
Compare more hinge-mortising options
 Option 1 Yonico 1/2″ Hinge Mortise Bit – $10.95
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 Option 2 Adjustable Aluminum Hinge Jig – $16.43
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 Option 3 All-in-One Hinge, Lock & Latch Jig Kit – $58.99
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How to Rout a Hinge Mortise Step by Step
- Prep and mark the door: Lay the door flat on a stable bench, and mark each hinge location with a sharp mechanical pencil so the lines stay thin and accurate.
- Install and set the bit: Insert a 1/2-inch straight or spiral bit into the router collet and tighten securely. Set plunge depth to match your hinge leaf’s exact thickness (see above).
- Position the jig or template: If using a hinge template, clamp it to the marked location. If routing freehand, stay a consistent 1/16 inch inside your marked lines to leave room for cleanup.
- Rout the mortise: Start the router, plunge slowly to full depth, and move it in smooth, controlled passes across the marked area. Don’t force the cut — let the bit clear its own chips.
- Square the corners if needed: For square-corner hinges, square up the router’s rounded corners with a sharp chisel. For 1/4-inch radius hinges, skip this step — the router cut already matches.
- Test-fit and adjust: Set the hinge leaf into the mortise. It should sit flush with the door edge with no rocking. Trim high spots with the chisel rather than re-routing the whole mortise.
Common Mistakes to Avoid
- Using a bit that doesn’t match the hinge radius forces extra chisel work or leaves visible gaps at the corners.
- Setting the depth to the whole hinge instead of one leaf cuts the mortise roughly twice as deep as it should be.
- Skipping the test cut on scrap material means the first mistake happens on the actual door.
- Routing freehand without a template on more than one or two hinges invites inconsistent mortises that make the door sit unevenly.
Wear safety glasses and hearing protection, and keep the router unplugged while you change bits or adjust depth. If a mortise ends up oversized or the door edge gets damaged during the process, our guide on how to fix a hole in a wooden door covers the repair.
Frequently Asked Questions
What size router bit do I need for door hinges?
A 1/2-inch diameter straight or spiral up-cut bit is the standard size for door hinge mortises. Its round profile cuts a 1/4-inch corner radius, which matches most residential butt hinges without any extra squaring.
Can I cut a hinge mortise with a chisel instead of a router?
Yes. A sharp chisel and mallet can cut a hinge mortise entirely by hand, and it’s the traditional method for one or two hinges. A router is faster and more consistent across multiple hinges or an entire set of doors.
How deep should a hinge mortise be?
The mortise depth should match the thickness of one hinge leaf, typically about 0.134 inch for standard-weight residential hinges and up to 0.180 inch for heavy-weight hinges. Measure your specific hinge with calipers rather than assuming a standard figure.
What’s the difference between square and radius hinge corners?
Square-corner hinges have sharp 90-degree corners and need hand-chiseling after routing, since a round bit always leaves rounded corners. Radius-corner hinges (1/4 inch or 5/8 inch) have rounded corners that a matching-diameter router bit cuts directly, with no chisel work needed.
Do I need a hinge template jig, or can I rout freehand?
For a single door or two, careful freehand routing along marked lines works fine. For multiple doors or hinges, a template jig keeps every mortise identical in size and position, which matters more as the hinge count goes up.
Match the bit diameter to your hinge’s corner radius, set the plunge depth to the leaf thickness, and test-fit before committing to the final cut. Getting those three details right is what separates a hinge that sits flush from one that binds or gaps.
