Garden Hose Thread Size Calculator
Calculate GHT thread specifications for male (MHT) and female (FHT) garden hose connections. Complete dimensional data per ASME B1.20.7 standard.
Select GHT Thread Type
Male threads are on hose ends and nozzles. Female threads are on spigots and faucets.
Thread Specifications
Select thread type and click
"Get Thread Specifications" to view results
GHT vs NPT: Key Differences
| Feature | Garden Hose Thread (GHT) | NPT (Pipe Thread) |
|---|---|---|
| Thread Type | Straight (parallel) | Tapered (1:16 ratio) |
| Nominal Size | 3/4" only | Multiple sizes (1/8" to 6"+) |
| Threads Per Inch | 11.5 TPI | Varies by size (8-27 TPI) |
| Sealing Method | Rubber washer in female end | Thread interference + sealant |
| Application | Garden hoses, outdoor connections | Plumbing, gas, industrial piping |
| Standard | ASME B1.20.7 | ASME B1.20.1 |
Common Confusion:
GHT is often confused with 3/4" NPT, but they are NOT compatible! GHT has straight threads and relies on a rubber washer for sealing, while NPT has tapered threads that seal through thread interference. Always use proper GHT to NPT adapters when connecting garden hoses to NPT fittings.
GHT Comparison Chart: Male vs Female
| Specification | Male (MHT) | Female (FHT) |
|---|---|---|
| Major Diameter | 1.0625" (27.0 mm) | 1.0725" (27.2 mm) |
| Minor Diameter | 0.9555" (24.3 mm) | 1.0055" (25.5 mm) |
| Pitch Diameter | 1.0090" (25.6 mm) | 1.0090" (25.6 mm) |
| TPI | 11.5 | 11.5 |
| Thread Depth | 0.0535" (1.36 mm) | 0.0335" (0.85 mm) |
| Common Use | Hose ends, nozzles, sprinklers | Faucets, spigots, connectors |
What is Garden Hose Thread (GHT)?
Garden Hose Thread (GHT) is a straight thread standard used in North America for connecting garden hoses, sprinklers, nozzles, and outdoor faucets. Standardized by ASME B1.20.7, GHT ensures compatibility across garden hose products from different manufacturers.
Key Characteristics
- Thread Type: Straight (parallel) threads
- Single Size: 3/4" nominal size only
- TPI: 11.5 threads per inch (standard)
- Sealing: Rubber washer in female end
- Hand-Tightenable: No tools required for installation
Why Straight Threads?
- Easy Connection: Hand-tight assembly without tools
- Reusable: Can be connected/disconnected many times
- Washer Seal: Rubber washer provides reliable seal
- Quick Setup: Fast attachment for seasonal use
- No Sealant: No tape or pipe dope needed
How to Identify GHT Threads
Visual Identification
- Thread Profile: Look for straight, parallel threads (not tapered). If you look along the length of the threads, they should be uniform diameter, not tapering.
- Rubber Washer: Female GHT fittings typically have a black rubber washer visible inside the fitting. This is the primary sealing mechanism.
- Thread Count: Count threads over 1 inch - GHT has 11.5 threads per inch. NPT has varying TPI depending on size (3/4" NPT has 14 TPI, not 11.5).
- Application Context: If it's on a garden hose, outdoor faucet, sprinkler, or nozzle, it's likely GHT.
Measurement Tips
- Male Thread OD: Measure the outer diameter of male threads with calipers. GHT male should measure 1.0625" (27.0 mm) at the major diameter.
- Female Thread ID: Measure the inner diameter of female threads. GHT female should measure approximately 1.0725" (27.2 mm) at the major diameter.
- Pitch Measurement: Measure the distance across 11-12 threads (should be close to 1" for GHT at 11.5 TPI).
GHT Applications and Uses
Male GHT (MHT) Applications
- Garden hose ends (male coupling)
- Spray nozzles and wands
- Sprinkler heads and oscillating sprinklers
- Hose-end fertilizer applicators
- Pressure washer adapters
- Hose repair fittings (male end)
- Quick-connect male adapters
- Shut-off valves (male side)
Female GHT (FHT) Applications
- Outdoor faucets and hose bibs (spigot end)
- Garden hose connectors (female coupling)
- Y-splitters and manifolds
- Hose timers and flow meters
- Backflow preventers
- Hose repair fittings (female end)
- Quick-connect female adapters
- Sprinkler system connections
Why GHT for Outdoor Use?
GHT's straight thread design with rubber washer sealing makes it ideal for seasonal outdoor use. Unlike tapered pipe threads that can seize over time, GHT connections can be easily attached and removed year after year. The hand-tight assembly means no tools are needed, making setup quick and convenient for residential users.
Common GHT Adapters and Fittings
GHT to NPT Adapters
The most common adapter type, used to connect garden hoses to standard pipe threads:
- GHT Female to NPT Male: Connect hose to threaded pipe or fitting
- GHT Male to NPT Female: Connect sprinkler/nozzle to pipe thread
- Common Sizes: 3/4" GHT to 1/2" or 3/4" NPT
- Materials: Brass (most common), plastic, stainless steel
Quick-Connect Systems
- Quick-Disconnect Couplers: Male and female halves for tool-free connection
- Push-Fit Adapters: Push hose onto barbed fitting
- Cam-Lock Fittings: Industrial-style quick connects
Specialty Adapters
Y-Splitters
One female GHT input, two male GHT outputs. Allows connection of two hoses or devices to a single spigot.
Swivel Adapters
Rotating collar prevents hose twisting. Reduces kinks and makes hose handling easier.
Extension Adapters
Male-to-female straight connector. Used to join two hoses or extend connection length.
Shut-Off Valves
Inline valve with GHT connections. Allows flow control without returning to faucet.
Related Calculators
Engineering Notes & Disclaimer
Standards Compliance: All dimensions in this calculator are based on ASME B1.20.7 (Garden Hose Coupling Threads) standard specifications.
Thread Compatibility: GHT is NOT compatible with NPT or other pipe thread standards. Always use proper adapters when connecting GHT to NPT fittings. Forcing incompatible threads can cause damage and leaks.
Washer Replacement: The rubber washer in female GHT fittings should be inspected regularly and replaced if cracked, compressed, or damaged. A damaged washer is the most common cause of leaks.
Hand-Tight Only: GHT connections are designed for hand-tight assembly. Using wrenches or pliers can damage threads and crush the rubber washer, causing leaks.
Pressure Limitations: Garden hose threads are typically rated for residential water pressure (40-80 PSI typical). Do not use GHT for high-pressure applications without verifying fitting pressure ratings.
Seasonal Storage: Disconnect and drain hoses before freezing weather. Frozen water can damage both the hose and threaded connections.
Professional Verification: This calculator is for reference purposes only. Always verify thread compatibility before purchasing fittings or adapters. When in doubt, consult with a plumbing or irrigation professional.
Liability: The user assumes all responsibility for proper application of this information. PipeSizing.net and its operators are not liable for any damages or losses resulting from use of this calculator.