Mercury 3 vs GPT Luna Latest: cost comparison
Prices updated 2026-10-27 · computed from live provider data
Short answer: Mercury 3 is cheaper on a
3:1 input/output blend — $0.163 per million tokens versus
$0.200, a 19% difference.
GPT Luna Latest offers the larger context window at 1,050,000 tokens, against 1,000,000 for Mercury 3.
Head to head
| Mercury 3 | GPT Luna Latest | |
|---|---|---|
| Input, per 1M tokens | $0.100 | $0.100 |
| Output, per 1M tokens | $0.350 | $0.500 |
| Blended 3:1, per 1M | $0.163 | $0.200 |
| Context window | 1,000,000 | 1,050,000 |
| Vendor | inception | ~openai |
Monthly cost at real volumes
| Workload (input / output) | Mercury 3 | GPT Luna Latest |
|---|---|---|
| 1M in / 250K out | $0.188 | $0.225 |
| 10M in / 2.5M out | $1.88 | $2.25 |
| 100M in / 25M out | $18.75 | $22.50 |
Which should you pick?
Pick GPT Luna Latest when you need the longer context window (1,050,000 vs 1,000,000 tokens). Pick Mercury 3 when price per token dominates your workload — high-volume classification, extraction, or batch summarisation.