What does this fine-tune cost to run?
Training cost is tokens, not examples. Enter what you have; the estimate does the rest.
| Training tokens | — |
| Throughput | — |
| GPU hours | — |
| VRAM needed | — |
| Fits this GPU | — |
Throughput is a 6·N flops/token estimate with a measured efficiency factor. Real runs vary by 20-40% with framework, sequence packing and dataset shape.
Why tokens, not examples
A training step costs roughly 6 x N floating point operations per token,
where N is the active parameter count. So the bill scales with tokens seen, not with how
many rows your JSONL has.
Five thousand examples at 200 tokens is a quarter of the compute of five thousand examples at 800 tokens — but people compare the two as if they were the same job.
Where the estimate drifts
- Sequence packing can raise effective throughput 30-60% by removing padding.
- Framework choice matters more than the GPU. Unsloth's kernels and a stock TRL loop differ by more than a 4090 and an A100 on small models.
- Data loading becomes the bottleneck when the dataset does not fit in page cache.
- Checkpoint saving can add minutes per epoch on network storage.
The number that actually matters
Rent by the hour and the training run is almost always cheap: a few dollars. The expensive parts are the labelling, the failed attempts and the evaluation. Budget accordingly — see the full guide.