NLP Lineage

27 February 2025 · Language modelling

GPT-4.5

GPT-4.5

OpenAI

Date
27 February 2025
What the date marks
Model release
Kind
Model
Organisation
OpenAI
Access
API only
Threads
In the guided tour
Chapter 14. Where the threads meet now
Learning phases
2. How LLMs are trained

Too recent for its influence to be judged: no later milestone in the data descends from it yet. How levels are decided

Figures quoted here are reported by the organisation that built it, not independently verified.

Read the primary source (openai.com)

Full summary in progress. Until then, this page shows the milestone's record from the research data.

What it changed

Before it

Each generation had come from more pretraining scale.

The problem

Was there still headroom in scaling pretraining alone, now that reasoning was the growth area?

What it introduced

OpenAI's largest pretraining scale-up, positioned on warmth and fewer hallucinations rather than reasoning.

Why it matters

Read in hindsight as the end of the pure-pretraining era. It was retired within months as the reasoning line took over.

What modern models inherit

A datapoint on the diminishing returns of pretraining scale alone.

What came next

GPT-5 unified the reasoning and chat lines instead of scaling pretraining further.

Before and after

The milestones it descends from, and the milestones that descend from it. Work developed alongside it is not counted. Weak links are left out unless you include them.

Before: where it came from

GPT-4.5 has 38 documented ancestors across 8 chapters, reaching back to Recurrent networks in 1990. Showing its direct parents and the 16 turning points among them.

GPT-4.5 has 38 documented ancestors across 8 chapters, reaching back to Recurrent networks in 1990. Showing all of them.

GPT-4.5 has 43 recorded ancestors, including indirect ones, across 8 chapters, reaching back to Recurrent networks in 1990. Showing its direct parents and the 16 turning points among them.

GPT-4.5 has 43 recorded ancestors, including indirect ones, across 8 chapters, reaching back to Recurrent networks in 1990. Showing all of them.

  1. 2025GPT-4.5This milestone.
  2. 2024GPT-4oGPT-4.5 built directly on thisChapter 11. Seeing and hearing
  3. 2023GPT-4VGPT-4o built directly on thisChapter 11. Seeing and hearing
  4. 2023GPT-4 Turning pointGPT-4o built directly on thisChapter 7. The assistant goes public
  5. 2022GPT-3.5 Turning pointGPT-4 succeeded thisChapter 7. The assistant goes public
  6. 2022InstructGPT Turning pointGPT-4 built directly on thisChapter 6. Teaching models what people want
  7. 2021FLANInstructGPT was influenced by thisChapter 6. Teaching models what people want
  8. 2020RLHF for summarisation Turning pointInstructGPT built directly on thisChapter 6. Teaching models what people want
  9. 2020GPT-3 Turning pointInstructGPT built directly on this
    GPT-3.5 built directly on this    Chapter 5. Scale becomes a science
  10. 2020Scaling laws Turning pointGPT-4.5 was influenced by thisChapter 5. Scale becomes a science
  11. 2019T5 Turning pointFLAN was influenced by thisChapter 4. Pretrain once, use everywhere
  12. 2019C4 Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  13. 2019RLHF for LMsRLHF for summarisation built directly on thisChapter 6. Teaching models what people want
  14. 2019Sparse Transformer Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  15. 2019GPT-2 Turning pointScaling laws was influenced by thisChapter 4. Pretrain once, use everywhere
  16. 2019WebTextGPT-2 was influenced by thisChapter 4. Pretrain once, use everywhere
  17. 2018BERT Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  18. 2018SentencePieceT5 built directly on thisChapter 4. Pretrain once, use everywhere
  19. 2018GPT-1GPT-2 built directly on thisChapter 4. Pretrain once, use everywhere
  20. 2018ELMoBERT was influenced by thisChapter 4. Pretrain once, use everywhere
  21. 2018ULMFiTBERT was influenced by thisChapter 4. Pretrain once, use everywhere
  22. 2017CoVeELMo was influenced by thisChapter 3. Attention, then only attention
  23. 2017Transformer Turning pointScaling laws built directly on thisChapter 3. Attention, then only attention
  24. 2017RLHF originRLHF for summarisation built directly on thisChapter 6. Teaching models what people want
  25. 2016Layer normTransformer built directly on this
    GPT-2 built directly on this    Chapter 3. Attention, then only attention
  26. 2015Residual connectionsTransformer was influenced by thisChapter 3. Attention, then only attention
  27. 2015LM pretraining Turning pointGPT-1 was influenced by thisChapter 2. Words become vectors
  28. 2015BPE tokenizationGPT-2 built directly on thisChapter 2. Words become vectors
  29. 2015Luong attentionTransformer was influenced by thisChapter 3. Attention, then only attention
  30. 2014AdamTransformer was influenced by thisChapter 2. Words become vectors
  31. 2014GloVeELMo built directly on thisChapter 2. Words become vectors
  32. 2014Seq2seq Turning pointTransformer built directly on thisChapter 2. Words become vectors
  33. 2014Attention Turning pointTransformer built directly on thisChapter 3. Attention, then only attention
  34. 2014GRU / encoder-decoderAttention built directly on thisChapter 2. Words become vectors
  35. 2013word2vecELMo was influenced by thisChapter 2. Words become vectors
  36. 2011NLP from scratchELMo was influenced by thisChapter 1. Language as probability
  37. 2003Neural LMNLP from scratch was influenced by this
    word2vec was influenced by this    Chapter 1. Language as probability
  38. 1997LSTM Turning pointSeq2seq built directly on thisChapter 1. Language as probability
  39. 1990Recurrent networksLSTM was influenced by thisChapter 1. Language as probability
  1. 2025GPT-4.5This milestone.
  2. 2024GPT-4oGPT-4.5 built directly on thisChapter 11. Seeing and hearing
  3. 2023GPT-4VGPT-4o built directly on thisChapter 11. Seeing and hearing
  4. 2023GPT-4 Turning pointGPT-4o built directly on thisChapter 7. The assistant goes public
  5. 2022GPT-3.5 Turning pointGPT-4 succeeded thisChapter 7. The assistant goes public
  6. 2022WhisperGPT-4o was influenced by this (indirect influence)Chapter 11. Seeing and hearing
  7. 2022InstructGPT Turning pointGPT-4 built directly on thisChapter 6. Teaching models what people want
  8. 2021FLANInstructGPT was influenced by thisChapter 6. Teaching models what people want
  9. 2021CLIPGPT-4V was influenced by this (indirect influence)Chapter 11. Seeing and hearing
  10. 2020Vision TransformerCLIP built directly on thisChapter 11. Seeing and hearing
  11. 2020RLHF for summarisation Turning pointInstructGPT built directly on thisChapter 6. Teaching models what people want
  12. 2020GPT-3 Turning pointInstructGPT built directly on this
    GPT-3.5 built directly on this    Chapter 5. Scale becomes a science
  13. 2020Scaling laws Turning pointGPT-4.5 was influenced by thisChapter 5. Scale becomes a science
  14. 2019T5 Turning pointFLAN was influenced by thisChapter 4. Pretrain once, use everywhere
  15. 2019C4 Turning pointT5 was influenced by thisChapter 4. Pretrain once, use everywhere
  16. 2019RLHF for LMsRLHF for summarisation built directly on thisChapter 6. Teaching models what people want
  17. 2019Sparse Transformer Turning pointGPT-3 built directly on thisChapter 4. Pretrain once, use everywhere
  18. 2019GPT-2 Turning pointScaling laws was influenced by thisChapter 4. Pretrain once, use everywhere
  19. 2019WebTextGPT-2 was influenced by thisChapter 4. Pretrain once, use everywhere
  20. 2019Transformer-XLSparse Transformer was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  21. 2018BERT Turning pointVision Transformer was influenced by thisChapter 4. Pretrain once, use everywhere
  22. 2018SentencePieceT5 built directly on thisChapter 4. Pretrain once, use everywhere
  23. 2018GPT-1GPT-2 built directly on thisChapter 4. Pretrain once, use everywhere
  24. 2018ELMoGPT-1 was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  25. 2018ULMFiTGPT-1 was influenced by this (indirect influence)Chapter 4. Pretrain once, use everywhere
  26. 2017CoVeELMo was influenced by thisChapter 3. Attention, then only attention
  27. 2017Transformer Turning pointScaling laws built directly on thisChapter 3. Attention, then only attention
  28. 2017RLHF originRLHF for summarisation built directly on thisChapter 6. Teaching models what people want
  29. 2017ConvS2STransformer was influenced by this (indirect influence)Chapter 3. Attention, then only attention
  30. 2016Layer normTransformer built directly on this
    GPT-2 built directly on this    Chapter 3. Attention, then only attention
  31. 2015Residual connectionsTransformer was influenced by thisChapter 3. Attention, then only attention
  32. 2015LM pretraining Turning pointGPT-1 was influenced by thisChapter 2. Words become vectors
  33. 2015BPE tokenizationGPT-2 built directly on thisChapter 2. Words become vectors
  34. 2015Luong attentionTransformer was influenced by thisChapter 3. Attention, then only attention
  35. 2014AdamTransformer was influenced by thisChapter 2. Words become vectors
  36. 2014GloVeELMo built directly on thisChapter 2. Words become vectors
  37. 2014Seq2seq Turning pointTransformer built directly on thisChapter 2. Words become vectors
  38. 2014Attention Turning pointTransformer built directly on thisChapter 3. Attention, then only attention
  39. 2014GRU / encoder-decoderAttention built directly on thisChapter 2. Words become vectors
  40. 2013word2vecELMo was influenced by thisChapter 2. Words become vectors
  41. 2011NLP from scratchELMo was influenced by thisChapter 1. Language as probability
  42. 2003Neural LMNLP from scratch was influenced by this
    word2vec was influenced by this    Chapter 1. Language as probability
  43. 1997LSTM Turning pointSeq2seq built directly on thisChapter 1. Language as probability
  44. 1990Recurrent networksLSTM was influenced by thisChapter 1. Language as probability

After: what it led to

No documented descendants are recorded for GPT-4.5 without weak links.

No documented descendants are recorded for GPT-4.5 without weak links.

No recorded descendants are recorded for GPT-4.5.

No recorded descendants are recorded for GPT-4.5.

Direct links and their sources

Where it came from

Built directly on

Influenced by

What it led to

None recorded in the sources used.