US unbleached corrugated box manufacturing and delivery costs increased in both the first and second quarters of 2026, according to ResourceWise’s Box Cost Index reports. The underlying pressures changed between quarters, however. Gas contributed to the first-quarter increase before easing in the second, while freight and overhead continued to add pressure, and recovered fiber costs increased.
For buyers and suppliers using cost-based contract adjustments, these movements highlight why the reference should reflect the broader cost of manufacturing and delivering a box. The ResourceWise U.S. Unbleached Box Cost Index provides an independent, industry-average benchmark that both parties can incorporate into an agreed adjustment mechanism. Relief in one input does not necessarily mean that total box costs are falling.
The first half of 2026 marked a shift from the comparatively smaller quarterly cost movement recorded in the second half of 2025. Costs increased in Q1 and rose again in Q2, leaving the industry’s modeled cost base above its year-earlier level.
Q1’s increase was driven by upward pressure from gas, freight, and overheads. In Q2, gas moved lower, but increases elsewhere more than offset that relief.
The movement in gas illustrates why a single market indicator can provide an incomplete basis for cost-based contract adjustment.
While gas costs decreased, increases in recovered fiber, freight, and overhead more than offset that relief, causing the index to rise again in Q2. ResourceWise models those costs using facility data and engineering-based estimates, recalculating the relative weights of cost categories each quarter as the industry’s cost structure changes. This approach creates a far more reliable index than alternative fixed-weight approaches.
Freight contributed to upward cost movement in Q1 and Q2. Its continued influence reinforces the importance of examining the delivered box, including transportation beyond the manufacturing process.
For both parties, this raises a practical question about their contract’s adjustment mechanism: which costs does the reference capture? A benchmark focused on paper prices may provide useful information about the material while leaving transportation and other converting costs outside its scope.
The Index does not determine the price of an individual box or prescribe an identical adjustment for every agreement. Delivery distances, shipment requirements, product specifications, service needs, and margins vary. Buyers and suppliers negotiate the starting price, adjustment formula, timing, and pass-through terms, including any modifiers. The Index supplies the common reference for cost movement; their agreement determines how that movement affects the contract price.
The first-half cost trends reinforce the importance of agreeing on what a contract’s adjustment mechanism is intended to achieve. For parties seeking to pass through changes in industry, manufacturing, and delivery costs, the quarterly Index provides a consistent reference for movements in either direction.
Planning requires a separate view. The Nowcast estimates the upcoming quarterly Index before its official release, while the Box Cost Forecast provides an 18-month outlook and analysis of expected cost drivers. These products support budgeting and sourcing decisions. The official quarterly Index remains authoritative for contractual application unless the parties specifically agree otherwise.
Teams should also separate Index movement from spending. Packaging expenditure depends on purchase volumes, product mix, adjustment timing, and contract formulas, as well as underlying costs. A national cost increase will not produce an identical percentage change in an individual company’s budget.
ResourceWise’s US Unbleached Box Cost Index combines researched mill and corrugator asset data, proprietary engineering-based models, and proprietary and third-party pricing inputs. Facility-level estimates are aggregated into an industry-average measure covering the full stack of costs required to make a corrugated box.
A separately managed ResourceWise Benchmarking Team creates and maintains the Index. Commercial personnel do not influence published values, and ResourceWise does not alter the Index at a buyer’s or seller’s request to achieve a particular commercial outcome. That independence gives both parties a shared reference when they choose a cost-based adjustment mechanism.
The first-half results show why a contract adjustment reference needs to account for the combined effect of changing manufacturing and delivery costs. The ResourceWise U.S. Unbleached Box Cost Index gives buyers and suppliers an independent benchmark covering those broader economics. Learn more about what the Index measures, how it can support agreed price adjustment mechanisms, and how the Nowcast and Forecast complement it with earlier visibility and longer-term planning insights.