GPT-3.5 Turbo Instruct vs GPT-5.6 Sol Pro
GPT-3.5 Turbo Instruct costs 10.0x less per output token than GPT-5.6 Sol Pro ($2.00 vs $20.00 per million). Updated October 22, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $2.00
- Coding
- No data
- Overall
- No data
- Output $/M
- $20.00
GPT-3.5 Turbo Instruct or GPT-5.6 Sol Pro: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick GPT-3.5 Turbo Instruct for output tokens 10.0x cheaper ($2.00 vs $20.00 per million).
No benchmark has tested both yet. GPT-3.5 Turbo Instruct has results on METR time horizons; GPT-5.6 Sol Pro on WeirdML, APEX-Agents and SimpleBench. Compare them on price and context instead.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Long documents
Listed context window
GPT-5.6 Sol Pro
GPT-5.6 Sol Pro takes 1.05M tokens against 4K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-3.5 Turbo Instruct
GPT-3.5 Turbo Instruct $0.0025, GPT-5.6 Sol Pro $0.014 per turn.
List prices
At a glance
- Coding index
- GPT-3.5 Turbo Instruct not benchmarked, GPT-5.6 Sol Pro not benchmarked.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- GPT-3.5 Turbo Instruct $2.00 against GPT-5.6 Sol Pro $20.00 per million output tokens, 10.0x apart.
- Context window
- GPT-3.5 Turbo Instruct takes 4K tokens, GPT-5.6 Sol Pro 1.05M.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
CodingDirectional onlySix of these boards feed the Vibe Coding Index1 board measured
| Benchmark | GPT-3.5 Turbo Instruct | GPT-5.6 Sol Pro | Leader |
|---|---|---|---|
| WeirdML | Not measured | 89.4% | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 38 boards here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | GPT-3.5 Turbo Instruct | GPT-5.6 Sol Pro | Leader |
|---|---|---|---|
| APEX-Agents | Not measured | 51.4% | Only GPT-5.6 Sol Pro measured |
| METR time horizons | 21.5% | Not measured | Only GPT-3.5 Turbo Instruct measured |
| Neither model has a result on the other 39 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | GPT-3.5 Turbo Instruct | GPT-5.6 Sol Pro | Leader |
|---|---|---|---|
| SimpleBench | Not measured | 71.7% | Only GPT-5.6 Sol Pro measured |
| Chess puzzles | Not measured | 68.0% | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 20 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | GPT-3.5 Turbo Instruct | GPT-5.6 Sol Pro | Leader |
|---|---|---|---|
| FrontierMath, tier 4 | Not measured | 80.5% | Only GPT-5.6 Sol Pro measured |
| Neither model has a result on the other 12 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
GPT-3.5 Turbo Instruct costs less
Repository review
50K input + 3K output tokens
GPT-3.5 Turbo Instruct costs less
Agent loop
200K input + 10K output tokens
GPT-3.5 Turbo Instruct costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | OpenAI GPT-3.5 Turbo Instruct | OpenAI GPT-5.6 Sol Pro |
|---|---|---|
| Maker | OpenAI | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 28, 2023 | July 9, 2026 |
| Context window | 4K | 1.05M |
| Input $/Mtok | $1.50 | $4.00 |
| Output $/Mtok | $2.00 | $20.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-3.5 Turbo Instruct better than GPT-5.6 Sol Pro for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick GPT-3.5 Turbo Instruct for output tokens 10.0x cheaper ($2.00 vs $20.00 per million).
Which is cheaper, GPT-3.5 Turbo Instruct or GPT-5.6 Sol Pro?
GPT-3.5 Turbo Instruct costs $1.50 per million input tokens and $2.00 per million output tokens; GPT-5.6 Sol Pro costs $4.00 and $20.00. Cost per solved task is known for neither of them.
Which has the bigger context window, GPT-3.5 Turbo Instruct or GPT-5.6 Sol Pro?
GPT-5.6 Sol Pro, with 1.05M tokens against 4K.
Has any benchmark tested both GPT-3.5 Turbo Instruct and GPT-5.6 Sol Pro?
No benchmark has tested both yet. GPT-3.5 Turbo Instruct has results on METR time horizons; GPT-5.6 Sol Pro on WeirdML, APEX-Agents and SimpleBench. Compare them on price and context instead. Data as of October 22, 2026.