Claude Haiku vs GPT-4o Mini Cost Showdown
GPT-4o mini costs $0.15/$0.60 per million tokens. Claude Haiku 4.5 costs $1.00/$5.00. On raw price, GPT-4o mini is 6.7x cheaper on input and 8.3x cheaper on output. That is not a rounding error. So why would anyone use Haiku?
Because price per token is not price per result. The cheapest model is the one that gives you correct output in the fewest attempts at the lowest total cost. Sometimes that is GPT-4o mini. Sometimes it is not.
The Setup
The budget tier comparison as of April 2026:
| Metric | Claude Haiku 4.5 | GPT-4o mini |
|---|---|---|
| Input per MTok | $1.00 | approximately $0.15 |
| Output per MTok | $5.00 | approximately $0.60 |
| Context window | 200K tokens | 128K tokens |
| Max output | 64K tokens | approximately 16K tokens |
| Batch input | $0.50/MTok | approximately $0.075/MTok |
| Batch output | $2.50/MTok | approximately $0.30/MTok |
| Cache read | $0.10/MTok | different system |
GPT-4o mini wins on every price line. That much is indisputable. The question is whether price per token translates to price per successful outcome for your specific workload.
The Math
Scenario 1: High-volume classification (10K calls, 500 input + 50 output tokens)
Claude Haiku 4.5:
- Input: 5M tokens at $1.00/MTok = $5.00
- Output: 500K tokens at $5.00/MTok = $2.50
- Total: $7.50
GPT-4o mini:
- Input: 5M tokens at $0.15/MTok = $0.75
- Output: 500K tokens at $0.60/MTok = $0.30
- Total: $1.05
GPT-4o mini costs $1.05 vs Haiku’s $7.50. That is 7.1x cheaper for the same classification task assuming equal accuracy.
Scenario 2: Document analysis requiring 150K context
Claude Haiku 4.5 (handles 200K context):
- Input: 150K tokens at $1.00/MTok = $0.15
- Output: 2K tokens at $5.00/MTok = $0.01
- Total: $0.16 per call
GPT-4o mini (caps at 128K context): Cannot process this request at all. The alternative is GPT-4o at $2.50/$10.00 per MTok:
- Input: 150K tokens at $2.50/MTok = $0.375
- Output: 2K tokens at $10.00/MTok = $0.02
- Total: $0.395 per call
Haiku is 2.5x cheaper than the GPT-4o fallback because GPT-4o mini simply cannot handle the context length. At 10,000 calls, that difference is $1,600 vs $3,950, saving $2,350 with Haiku.
Scenario 3: Long-form generation needing 30K output tokens
Claude Haiku 4.5 (64K output limit): Single call, $0.15 output cost GPT-4o mini (approximately 16K output limit): Needs 2 calls minimum with context management overhead. Total cost may exceed Haiku despite lower per-token rate because you pay for input tokens twice.
The Technique
The decision framework for choosing between these budget models requires evaluating four dimensions:
Dimension 1: Task complexity. For well-defined, simple tasks like binary classification, sentiment labels, or entity extraction, GPT-4o mini’s quality is typically sufficient and its 7x price advantage is a clear win. For tasks requiring nuanced judgment, following complex instructions, or maintaining consistency across long outputs, benchmark both models on your actual data before deciding.
Dimension 2: Context requirements. If any requests need more than 128K tokens of context, GPT-4o mini is eliminated. Haiku supports 200K tokens. This single dimension overrides all pricing considerations.
Dimension 3: Output length. Haiku generates up to 64K output tokens per request. GPT-4o mini caps around 16K. For tasks producing more than 16K tokens, GPT-4o mini requires multiple calls with additional input token costs and orchestration complexity.
Dimension 4: Volume economics. At 100 calls per month, the cost difference between Haiku and GPT-4o mini is negligible (dollars, not hundreds). At 1M+ calls per month, the 7x gap translates to hundreds or thousands of dollars. Volume determines whether the price difference matters at all.
Apply Claude’s caching to narrow the gap: Haiku cache reads cost $0.10/MTok, which is only 33% cheaper than GPT-4o mini’s standard input rate of $0.15/MTok. Caching helps, but it does not fully close the 6.7x input price gap.
The Tradeoffs
GPT-4o mini wins when:
- Tasks are simple classifications, extractions, or templated generations
- All inputs are under 128K tokens and outputs under 16K tokens
- Volume exceeds 100K calls per month where the 7x gap is significant
- You do not need prompt caching features
Claude Haiku wins when:
- Documents exceed 128K tokens making GPT-4o mini ineligible
- Output must exceed 16K tokens per request
- Quality on nuanced tasks justifies the cost premium per call
- Shared context benefits from $0.10/MTok cache reads across many requests
- The alternative is not GPT-4o mini but GPT-4o at $2.50/$10.00
The honest assessment: For pure cost optimization on simple tasks at high volume, GPT-4o mini at $0.15/$0.60 is extremely hard to beat. Haiku is not the cheapest option for straightforward work. It is the cheapest capable option for workloads that exceed what mini can handle.
Implementation Checklist
- Profile your tasks by complexity tier and identify which are truly simple
- Check context length requirements for every task category
- Run quality benchmarks on 500 samples with both models side by side
- Calculate cost at your actual monthly volume for the top candidate
- Consider a split routing strategy: GPT-4o mini for simple tasks, Haiku for everything else
- Factor in Haiku batch pricing at $0.50/$2.50 for async workloads
Measuring Impact
- Cost per successful completion, not just cost per API call
- Error and retry rate per model: if Haiku succeeds in 1 call where mini needs 3, adjust math
- Context utilization: what percentage of calls actually require over 128K tokens
- Monthly spend delta: track the actual realized difference, not the theoretical 7x gap
- Quality score distributions per model per task type reviewed weekly