The amount of computation going into AI models doubles every four months.

Judge as of 2026-02-28. The claim concerns the growth rate of training compute for frontier or notable AI models. True: credible estimates from around 2025–2026 put the doubling time for training compute of frontier or notable models at about 3–5 months, which is a growth of roughly 5–16x per year. Mostly true: the estimate is about 5–6 months, or 2.5–3 months. Mixed: estimates are split, with some credible sources near 4 months and others substantially longer. Mostly false: the best estimates are about 6–9 months, which is real exponential growth overstated, or the 4-month figure applies only to a narrow subset or an older era (for example 2012–2018) but is presented as current and general. False: the doubling time is clearly over about 9 months, or compute is not growing exponentially.

Set before the research began.

1. E1 Trends in AI Epoch AI · 5 February 2026

   “Training compute for frontier language models has been doubling every 5.2 months since 2020.”

2. E2 Research and Development Stanford HAI (AI Index 2025)

   “New research finds that the training compute for notable AI models is doubling approximately every five months, dataset sizes for training LLMs every eight months, and the power required for training annually.”

3. E3 Training compute of frontier AI models grows by 4-5x per year Epoch AI · 28 May 2024

   “All in all, we recommend summarizing the recent trend of compute growth for notable and frontier models with the 4-5x/year figure.”

4. E4 Projecting AI Training Power Demand Epoch AI (Substack) · 11 August 2025

   “The primary factor driving this growth is the scaling of the compute used to train models, at a rate of 4-5x per year.”

Epoch AI estimates that training compute for frontier language models has doubled every 5.2 months since 2020 (E1). Its recommended summary figure for growth in notable and frontier models is 4–5x per year (E3, E4), which works out to a doubling time of roughly 5–6 months. The AI Index 2025 gives about five months for notable models (E2). These estimates show fast exponential growth, but they sit at the top of the 3–5 month range or a little above it, which fits the "about 5–6 months" band for mostly true better than the four-month figure in the claim.