TI HI Calculator Explained: Cases per Layer, Layers per Pallet

On any pallet pattern sheet, warehouse load diagram, or order from a retail buyer, you will eventually see a number that looks like 12 × 5 or TI 12, HI 5. That is TI / HI notation, and it is the shortest way to describe how a pallet is built.

This guide covers what TI and HI mean, how to calculate them for any case-pallet combination, how to read a pallet pattern sheet, and the situations where the calculated TI / HI diverges from the one the warehouse actually builds.

1. What TI and HI Mean

TI is the number of cases on one layer of the pallet. It stands for tier or items per layer. Some references use the term “layer count” or “per-layer count”, but TI is the shorthand on every pallet sheet.

HI is the number of layers stacked on the pallet. It stands for height (in layers, not inches). It is sometimes written as “layers high” or “stack height in layers”.

Total cases per pallet = TI × HI.

A pallet labeled TI 16, HI 12 has 16 cases per layer and 12 layers, giving 192 total cases. The same pallet might be written 16 × 12 on a pattern sheet, or 192 cs TI16 HI12 on a shipping label.

2. Why TI / HI Notation Exists

Before pallets were built by robotic palletizers, warehouse workers followed written or printed instructions for how to stack. A single number (the total case count) tells you how many boxes to put on the pallet, but not how to arrange them. A pattern diagram tells you how to arrange them, but takes space to read.

TI × HI is the compromise. It tells the stacker:

• How many cases to put on each layer
• How many layers to build

A single glance at 12 × 5 conveys “stack 12 per layer, go 5 layers high, total 60 cases”. Every major WMS, ERP, and shipping manifest system accepts TI / HI as the canonical pallet descriptor for this reason.

Retailers use TI / HI to enforce case-pack compliance. A Walmart or Tesco order often specifies a required TI / HI for inbound pallets, and receivers reject pallets that do not match. A supplier who ships TI 14, HI 5 when the order called for TI 12, HI 6 may take a chargeback even if the total case count is identical.

3. How TI Is Calculated

TI depends on three things: case footprint, pallet footprint, and pattern type.

For column stacking with a single orientation, TI is straightforward:

TI = floor(pallet length / case length) × floor(pallet width / case width)

For a 12 × 10-inch case on a 48 × 40-inch GMA pallet:

TI = floor(48 / 12) × floor(40 / 10) = 4 × 4 = 16

That gives you TI for one orientation. Because rotating the case 90 degrees changes which dimension runs along which side of the pallet, you always check the alternate orientation:

TI (rotated) = floor(48 / 10) × floor(40 / 12) = 4 × 3 = 12

Take the larger of the two. TI = 16 in this example.

TI for interlocking patterns

Interlocking alternates case orientation every other layer. The TI on a given layer might be lower than the column-stack TI because rotated layers lose some pattern efficiency. A common interlocking variant is:

• Odd layers: 4 × 4 = 16 cases (same as column)
• Even layers: 5 × 3 = 15 cases (rotated, cases slightly offset to interlock)

This is why interlocking pallets often show two TI values, such as TI 16/15, HI 10. Total cases = (16 × 5) + (15 × 5) = 155.

TI for pinwheel and hybrid patterns

Pinwheel rotates cases within a single layer. Hybrid mixes column and interlock across layers. Both can produce TI values that are not simple multiplications. Warehouse pattern sheets for these use a diagram rather than a single formula.

4. How HI Is Calculated

HI depends on case height, allowable total stack height, and (often) weight.

HI (height-limited) = floor((total allowed height minus pallet deck) / case height)

For an 8-inch-tall case on a GMA pallet with a 102-inch total height limit and a 5-inch deck:

HI = floor((102 minus 5) / 8) = floor(97 / 8) = 12

That gives the height-limited HI. Weight is a separate constraint:

HI (weight-limited) = floor((max pallet weight minus pallet weight) / (TI × case weight))

For 25 lb cases on a 40 lb GMA pallet at the common 2,500 lb dynamic-load planning figure and TI = 16:

HI = floor((2,500 minus 40) / (16 × 25)) = floor(2,460 / 400) = 6

The actual HI is the smaller of the two: HI = min(12, 6) = 6. Weight wins in this case, which is typical for dense products. Confirm the actual working load for your specific pallet construction and handling environment before committing.

This is the single most common source of error when a spreadsheet says one number and the warehouse builds another. The spreadsheet uses height alone and gets 12. The warehouse follows the weight-limited instruction and builds 6. Both are right, but the engineer who did the calculation forgot to check weight.

5. Reading a Pallet Pattern Sheet

A typical pallet pattern sheet from a WMS, a broker, or a carrier will include:

• Case dimensions (length × width × height, in inches or mm)
• Case weight (per case, in lb or kg)
• Pallet type and dimensions (GMA 48 × 40, EUR 1200 × 800, or custom)
• TI × HI (for example, 16 × 10 or TI 16, HI 10)
• Total cases (TI × HI)
• Total weight (including pallet weight)
• Pattern diagram (top-down view of one layer)
• Pattern type (column, interlock, pinwheel, hybrid)
• Notes (overhang allowance, stretch wrap specification, corner board usage)

Some retailer-provided sheets also include:

• SSCC barcode position (where to place the pallet identifier)
• Load height with wrap (total height including stretch wrap)
• Slip sheet or tier sheet usage
• Banding or shrink wrap pattern

A warehouse worker or palletizer operator follows the sheet exactly. A discrepancy between the sheet and the pallet, even by one case, is a reason to stop and verify.

6. Common TI / HI Scenarios and Their Patterns

Single SKU, standard case, GMA pallet

• Case: 12 × 10 × 8 in, 20 lb
• Pallet: GMA 48 × 40
• Height limit: 100 in total
• Planning load: 2,500 lb (common GMA figure)
• TI = 16, HI by height = 11, HI by weight = 7
• Final: TI 16, HI 7, total 112 cases
• Pattern: Column, 4 × 4

Tall light cases, EUR pallet

• Case: 300 × 200 × 150 mm, 3 kg
• Pallet: EUR 1200 × 800
• Height limit: 1800 mm
• Planning load: 1,500 kg (EPAL safe working load)
• TI = 16, HI by height = 11, HI by weight = 31
• Final: TI 16, HI 11, total 176 cases
• Pattern: Column, 4 × 4 (height-limited)

Heavy cases with weight constraint binding

• Case: 10 × 8 × 6 in, 40 lb
• Pallet: GMA 48 × 40
• TI = 24 (6 along 48 at 8-inch side, 4 along 40 at 10-inch side) or 20 (4 × 5 in the alternate orientation)
• HI by height = 15 (at 95 in clearance), HI by weight = floor(2,460 / (24 × 40)) = 2
• Final: TI 24, HI 2, total 48 cases
• Pattern: Column. Weight drives a very short stack.

Hybrid pattern for medium-weight product

• Case: 14 × 11 × 9 in, 18 lb
• Pallet: GMA 48 × 40
• Pattern: Column on bottom 3 layers (TI 12), interlock on top 4 (TI 11)
• Final: TI 12/11, HI 7, total 80 cases
• Notes: bottom preserves compression, top adds interlock stability

7. TI / HI and Box Compression Strength

The HI you choose directly sets the compression load on the bottom layer. For a uniform column stack with equal load sharing, each bottom-layer case carries roughly:

Bottom-layer load per case ≈ (HI minus 1) × case weight

So for HI = 10 layers of 20 lb cases in a column stack, the bottom-layer load is roughly 9 × 20 = 180 lb per case. Real-world loads deviate from this estimate because interlock, hybrid patterns, and uneven layer weights redistribute load unevenly across bottom-layer cases.

Box compression test (BCT) ratings need a safety factor on this value. A common rule is SF 3 for steady-state storage and SF 4 for a humid or long-storage environment. So a 180 lb bottom load requires a box rated for 540 to 720 lb BCT.

If the BCT rating is lower than that, either HI has to drop or the case has to move to a heavier board grade. This is where the Box Strength Calculator and the Pallet Calculator feed into each other: Pallet gives the HI, Box Strength tells you whether the HI is survivable.

8. TI / HI and Load Stability

HI also drives the center-of-gravity height, which drives stability during transport. As a rough rule:

• HI ≤ 6: low-CG, stable in most transport modes
• HI 7 to 10: moderate-CG, check lateral stability for road transport
• HI ≥ 11: high-CG, often requires stretch wrap with high containment force, corner boards, and sometimes banding

The Pallet Load Stability Calculator takes TI, HI, case weight, and pallet type and returns the tilt angle the load can survive.

9. Frequently Asked Questions

What does TI HI stand for in palletizing?

TI stands for tier (cases per layer). HI stands for height in layers. Total cases on the pallet equals TI × HI. The notation is standard on pallet pattern sheets, shipping labels, and retailer compliance specifications.

How do I calculate TI?

Divide the pallet length by the case length to get cases per row. Divide the pallet width by the case width to get rows per layer. Multiply the two for TI. Do it twice, once in each case orientation, and take the larger result.

How do I calculate HI?

Divide the available stacking height (total allowed height minus the pallet deck) by the case height and round down. That is the height-limited HI. Then divide the remaining pallet weight budget by the weight of one full layer (TI × case weight) and round down. That is the weight-limited HI. The actual HI is the smaller of the two.

Why does the TI on my pattern sheet not match my spreadsheet?

Three common reasons. First, interlocking patterns have different TI on alternate layers. Second, the spreadsheet may use one orientation while the warehouse uses the other. Third, the spreadsheet may not account for stretch wrap or corner board thickness, which eats 5 to 10 mm per side.

Can I have different TI on different layers?

Yes, especially in interlocking or hybrid patterns. A pallet specified as TI 16/15, HI 10 has 16 cases on odd layers and 15 on even layers for a total of 155. Some pattern sheets show this as (TI 16, HI 5) + (TI 15, HI 5).

What is the difference between TI HI and a pallet pattern?

TI and HI are the counts (how many cases per layer, how many layers). A pallet pattern is the spatial arrangement (where each case sits on the layer, which direction it faces, how it rotates from layer to layer). Two pallets with the same TI / HI can have different patterns (one column, one interlocking) and different stability and compression profiles.

Is there a standard TI HI for a given product?

No. TI / HI depends on case dimensions, pallet standard, weight, and the pattern the team chooses. Two products with similar weight but different dimensions can have wildly different TI / HI. Always calculate for the specific case and pallet combination.

Do retailers care about TI HI?

Yes. Many large retailers specify required TI / HI in their vendor compliance documents. Walmart, Tesco, Target, and similar retailers will reject or charge back pallets that arrive with the wrong TI / HI, even if the total case count is correct. The reason is that their receiving, slotting, and replenishment systems are tuned to the specified pattern.

Next Steps

Calculating TI / HI by hand works for one case-pallet combination. It does not scale when you are evaluating three case sizes across two pallet standards with four pattern types and an overhang constraint. The Pallet Calculator runs every viable orientation, pattern, and constraint combination, shows TI and HI side-by-side for each option, and generates a pattern sheet you can send to the warehouse.

For the full calculation method, see the how to calculate boxes per pallet guide. For the GMA vs EUR comparison that drives many of these numbers, see the GMA vs EUR pallet sizing guide.