Phi-4-reasoning training emissions
Microsoft released Phi-4-reasoning on April 30, 2025 (source).
How we got the range
Microsoft has not published what training Phi-4-reasoning emitted. We multiplied the compute it took by what each NVIDIA H100 uses and what the grid emits, at the low and high end of each assumption. The method, in full.
Inputs for Phi-4-reasoning| Input | Value | Source |
|---|
| Training compute | 9.34 × 10²³ FLOP | Epoch AI, Data on AI models, Phi-4-Reasoning (the Phi-4 base model it was built from, plus fine-tuning) |
|---|
| H100 peak (FP8, dense) | 1.98 × 10¹⁵ FLOP/s | NVIDIA, H100 specifications: 3,958 teraFLOPS FP8 with sparsity, dense is half |
|---|
| H100 rated power | 700 W | NVIDIA, H100 specifications: max TDP up to 700 W |
|---|
| Utilization, low | 0.3 share of peak | Epoch AI, estimation methods: typical language-model range 0.3 to 0.5 |
|---|
| Utilization, high | 0.5 share of peak | Epoch AI, estimation methods: typical language-model range 0.3 to 0.5 |
|---|
| PUE, low | 1.1 ratio | Google, data center efficiency: fleet quarterly PUE 1.10, trailing twelve months 1.09 (Q2 2026) |
|---|
| PUE, high | 1.4 ratio | LBNL, 2024 United States Data Center Energy Usage Report: U.S. average PUE 1.4 in 2023, p. 47 |
|---|
| Grid, low: Microsoft, market-based | 73.1 gCO2e/kWh | Microsoft, 2026 Environmental Data Fact Sheet: Scope 2 market-based 2,707,428 t (p. 3) over 37,026,353 MWh consumed (p. 6), fiscal 2025 |
|---|
| Grid, high: U.S. grid, location-based | 384.4 gCO2e/kWh | Ember via Our World in Data, carbon intensity of electricity, United States, 2025 |
|---|
- Most of the compute is the Phi-4 base model, which Microsoft’s model card says trained on 1,920 H100s for 21 days (about 968,000 GPU-hours). The reasoning fine-tune took 32 H100s for 2.5 days.
- Our method implies 262,000 to 437,000 GPU-hours, fewer than Microsoft’s card states, so this range is likely low.
Also cited: Microsoft, Phi-4 model card: 1,920 H100-80G, 21 days · Microsoft, Phi-4-reasoning model card: 32 H100-80G, 2.5 days
Last checked October 17, 2026. Every model