Amazon Raises the IPI Score Threshold to 400

In brief: an Amazon IPI score of 400 became the line to clear. The Inventory Performance Index (IPI) scores how efficiently you manage FBA stock. In 2020 Amazon raised the score needed to avoid storage limits from 350 to 400, measured from 14 May 2020 (week 20). Sellers under 400 by 21 June (week 26) could face storage limits from 1 July to 30 September 2020. And from 1 August 2020, going over your limit on any day of a month triggered a new overage charge: £7.80 a month for each cubic foot over the limit (excluding VAT) — on top of normal monthly storage and any long-term storage fees.

The IPI score 400 rules

Item	Detail
IPI threshold	Raised from 350 to 400 (from week 20, 2020)
Limits apply	Q3 2020 (1 July – 30 September) if IPI under 400 at week 26
Overage fee	£7.80 per cubic foot per month, from 1 August 2020
Charged when	Stock exceeds the limit on any day of the month

A worked example

A seller with an IPI of 370 is limited to 1,000 cubic feet but holds 1,150 on one day in August 2020. The 150 cubic feet over the limit cost £1,170 that month (150 × £7.80), plus their normal storage fees.

What it means for your bookkeeping

• Overage is a separate storage cost. Post it alongside, but distinct from, monthly storage fees so you can see what poor inventory performance costs.
• Storage is expensed as incurred. Storage and overage fees are normally a cost of the period, not part of stock value.
• Stock levels drive fees. Overstocking risks limits and overage; understocking has its own costs — see the 2024 low-inventory fee.
• VAT: fees billed in 2020 used the reverse charge for UK VAT-registered sellers — see VAT on Amazon fees.

How TrueBooks helps

TrueBooks posts storage and other FBA fees from every settlement to their own accounts in Xero with the right UK VAT for their date, so overage charges stand out. See the Amazon Xero integration.