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The design load that must be transferred across this truss joint.
This is the force the joint connection must resist, typically taken from the truss design drawing's joint reaction or chord force.
The manufacturer's ANSI/TPI 1 tested tooth capacity per unit of plate area.
From the plate manufacturer's own published values for that plate, in that timber species, at that orientation — tooth capacity is a tested property of a specific plate and it is not transferable between makers. The value also depends on the angle between the plate and the grain and on the angle of the load, so a single figure is a simplification the real design tables do not make.
Plate area needed (each side)
31 in²
Use your specific plate manufacturer's ANSI/TPI 1 rated tooth capacity — this value varies significantly by plate gauge, tooth pattern, and wood species.
- Total area (both side plates)
- 62 in²
They open the calculator with your figures already in it
Truss Plate (MPC) Connector Sizing Calculator: 31 in² — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Metal plate connector (MPC) capacity is governed by manufacturer-tested tooth values per the Truss Plate Institute (ANSI/TPI 1) — this calculator divides your required joint load by your own plate's rated capacity-per-area to estimate the plate area needed, applied to each of the two side plates
Inputs used
- Required Joint Load
- 4.5 kip
- Plate Rated Capacity (kN per cm²)
- 0.05
Intermediate steps
- Total area (both side plates)
- 62 in²
Confidence note: Use your specific plate manufacturer's ANSI/TPI 1 rated tooth capacity — this value varies significantly by plate gauge, tooth pattern, and wood species.
What this calculation does not cover
- One capacity-per-area number hides a direction. ANSI/TPI 1 tooth values are not a single figure for a plate — they shift with the angle between the load, the wood grain and the plate's own tooth slots, so the same plate on the same joint carries different loads depending on how it is turned. Applying one averaged value across a truss over-rates the joints loaded across the grain.
- Area is not fit. Teeth only work where they are pressed into solid wood, so what carries the joint is the contact area on each individual member, less whatever falls over the gaps between members and whatever lands too close to an end or an edge. The gross area returned here is always larger than the area doing the work, and at a joint where three or four webs converge at a sharp angle a plate of the required area may have nowhere to sit.
- The rated value assumes a full factory press. Plate capacity is tested with the teeth driven to complete embedment under the plant's press — a plate part-driven, hammered on site, or embedded in wood that has since dried and shrunk back from it does not develop the number entered above. A lifted or missing plate is a repair to the truss engineer's detail, not a bigger plate nailed over the top.
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This result is a specification — 31 in² — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Metal plate connector (MPC) capacity is governed by manufacturer-tested tooth values per the Truss Plate Institute (ANSI/TPI 1) — this calculator divides your required joint load by your own plate's rated capacity-per-area to estimate the plate area needed, applied to each of the two side plates
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