Version discipline
Changelog
Every default value on this site — GPU prices, electricity tariffs, model pricing, throughput benchmarks — carries a source and a capture date. This page is the record of what changed between captures and why. No silent edits to numbers; see the assumptions page for the current values themselves.
v0.3
2026-07-21- Fixed three factual errors: Anthropic cache-write pricing (was billed as "same as input"; actually 1.25× for 5-minute writes, 2× for 1-hour writes), Opus cache-read price, and ChatGPT Plus/Pro pricing in the "What a token actually costs" article.
- Replaced the Anthropic model table with the current lineup: Claude Fable 5, Opus 4.8, Sonnet 5 (introductory and standard pricing), Sonnet 4.6, and Haiku 4.5 — with separate 5-minute and 1-hour cache-write rates now that they price differently.
- Added a cache-TTL selector to the Prompt Economics calculator so 5-minute vs. 1-hour caching can actually be compared.
- Refreshed LCOI hardware defaults: A100 80GB price cut from $12,000 to $9,000; H100 SXM residual value cut from 30% to 25% (widened secondary-market bid-ask); added NVIDIA B200 and RTX 5090 presets.
- Refreshed electricity defaults from Eurostat H2-2025 and EIA 2025 data: US $0.08→$0.09/kWh, EU $0.15→$0.21/kWh, Germany $0.18→$0.26/kWh, Ireland $0.28→$0.29/kWh.
- Updated the PUE citation to the Uptime Institute 2025 Global Data Center Survey (15th annual); updated the discount-rate derivation to current FRED/Kroll figures (rate unchanged at 8%).
- Recomputed every worked example on the site against the new defaults, including the A100-vs-H100 unit-cost finding (A100 wins by more than before) and the US-vs-Ireland geography comparison.
- Added this changelog and capture-date badges on the homepage and calculator.
v0.2
2026-04-18- Reworked the LCOI formula: workload shape via separate prompt/output token counts, hardware-specific residual value via a capital recovery factor, a hybrid fixed-plus-per-GPU OpEx model, and hourly utilisation schedules.
- Added region-specific electricity and PUE presets for US, EU, Germany, and Ireland.
- Added the Prompt Economics calculator and the Workflow scenario builder.
v0.1
before 2026-04- Initial launch: LCOI calculator with a simplified capex/electricity/cooling formula (no residual value, no OpEx), referenced in early articles as the "naive" baseline superseded by v0.2.