Sustainability Methodology
How we calculate Blaire's environmental impact using Life Cycle Assessment (LCA) research
Our Approach
Every time someone swaps clothes on Blaire instead of buying new, we avoid the environmental impact of manufacturing a new garment. Our calculations are based on peer-reviewed Life Cycle Assessment (LCA) research from leading sustainability organizations.
We use conservative estimates and only count impact from items that are actually sold, ensuring our metrics reflect real-world environmental benefits.
Data Sources
WRAP UK (Waste & Resources Action Programme)
UK-based research organization providing data on clothing lifecycle carbon emissions and the environmental benefits of extending garment lifespans.
Ellen MacArthur Foundation
Global thought leader on circular economy, providing comprehensive data on textile water footprints and manufacturing impacts.
Quantis International
Environmental consulting firm specializing in LCA research for the fashion industry, providing detailed carbon footprint data by garment type.
Calculation Methodology
CO₂ Emissions Avoided
Manufacturing carbon footprint per category
Each clothing category has a specific carbon footprint based on manufacturing processes, materials, and transportation. When an item is swapped instead of bought new, we avoid these emissions entirely.
Category Baselines
Example: When someone buys a used hoodie on Blaire instead of buying new, we avoid approximately 18 kg of CO₂ emissions — equivalent to driving a car for 70 km.
Water Consumption Avoided
Manufacturing water footprint per category
Textile manufacturing is extremely water-intensive. Cotton cultivation, dyeing, and finishing processes require massive amounts of fresh water. By swapping clothes, we avoid this water consumption entirely.
Category Baselines
Example: A single pair of jeans requires 7,600 liters of water to produce — enough for one person to drink for 10 years. Every pair swapped on Blaire saves this water.
Marketplace Fees Avoided
Based on Vinted's fee structure
Most online marketplaces charge sellers a percentage-based fee plus a fixed transaction fee. Blaire has zero seller fees, meaning sellers keep 100% of their sale price.
Vinted Fee Structure (for comparison)
Example Calculations:
Shipping Costs Avoided
On traditional marketplaces, sellers typically pay €5.00 in shipping costs (average of Vinted €3.95-€5.95 and Depop €5.30-€7.00). Blaire's in-person drop-off model eliminates these costs entirely.
Substitution Rate
How we account for behavioral changes
Not every secondhand purchase replaces a new purchase — sometimes people buy secondhand items they wouldn't have bought new. We account for this with a substitution rate.
Conservative Scenario (0.5)
Assumes only 50% of swapped items replace new purchases. More cautious estimate accounting for "bonus purchases."
Bold Scenario (1.0) ✓ Current
Assumes 100% of swapped items replace new purchases. Based on research showing secondhand fashion primarily replaces new.
Currently, Blaire uses the Bold scenario (1.0) based on research showing that most secondhand fashion purchases do replace new purchases, especially among sustainability-conscious students.
Our Commitment to Transparency
We believe in honest, science-based impact reporting. Our calculations use peer-reviewed research and conservative estimates. We don't inflate numbers or make unverifiable claims.
All impact metrics are recalculated in real-time based on actual sales, ensuring our leaderboard always reflects true environmental benefits.
Questions about our methodology? Contact our team