Head to head · October 2026

GPT-6.1 Sol vs GPT-5.6 Terra API pricing

GPT-6.1 Sol costs 1.1 times less per token at an 80/20 mix. Input prices are within 5% of each other. Output costs 1.2x more on GPT-5.6 Terra.

OpenAI

GPT-6.1 Sol

General assistants and agents at mid-tier cost.

Vendor: OpenAI
Type: Frontier
SayGM in / out: $1.49 / $7.45
OpenRouter in / out: $2.11 / $10.55
Blended, 80/20: $2.682
Per 100M tokens: $268
Output share of bill: 56%
SayGM vs OpenRouter: 29% lower

OpenAI

GPT-5.6 Terra

General assistants, balanced cost and quality.

Vendor: OpenAI
Type: Frontier
SayGM in / out: $1.49 / $8.94
OpenRouter in / out: $2.11 / $12.66
Blended, 80/20: $2.980
Per 100M tokens: $298
Output share of bill: 60%
SayGM vs OpenRouter: 29% lower

§ 01

Monthly bill at three usage levels

Both models on SayGM. The bars show how the price ratio turns into dollars as volume grows.

Fig. 1Monthly bill at three usage levels

GPT-6.1 Sol on SayGM
GPT-5.6 Terra on SayGM

Side project5M in · 1M out

$15

$16

Production app50M in · 15M out

$186

$209

High volume500M in · 100M out

$1,490

$1,639

Show data as a table

	GPT-6.1 Sol on SayGM	GPT-5.6 Terra on SayGM
Side project (5M in · 1M out)	$15	$16
Production app (50M in · 15M out)	$186	$209
High volume (500M in · 100M out)	$1,490	$1,639

Usage is millions of input and output tokens per month. No caching discount applied. Source: published rate cards, October 2026 snapshot. Current prices on saygm.com.

§ 02

Verdict

A common pattern is to send routine requests to GPT-6.1 Sol and escalate to GPT-5.6 Terra on failure or low confidence. On one key, that is a model name change per request rather than a second provider account.

§ 03

Per-token prices

OpenRouter figures include its 5.5% top-up fee.

USD per million tokens, input and output. OpenRouter includes its 5.5% top-up fee. Snapshot from October 2026.
Model	SayGMin / out	OpenRouterin / out, fee incl.	SayGM vs OpenRouter80/20 blend
GPT-6.1 SolOpenAI	$1.49 / $7.45	$2.11 / $10.55	29% lower
GPT-5.6 TerraOpenAI	$1.49 / $8.94	$2.11 / $12.66	29% lower

Current SayGM rates

§ 04

GPT-6.1 Sol vs GPT-5.6 Terra questions

Which is cheaper, GPT-6.1 Sol or GPT-5.6 Terra?

GPT-6.1 Sol is about 1.1 times cheaper than GPT-5.6 Terra at an 80/20 input to output mix on SayGM, as of October 2026.

How much do GPT-6.1 Sol and GPT-5.6 Terra cost on OpenRouter?

Including the 5.5 percent top-up fee, GPT-6.1 Sol costs $2.11 input and $11 output per million tokens, and GPT-5.6 Terra costs $2.11 and $13.

Can I use GPT-6.1 Sol and GPT-5.6 Terra with one API key?

Yes. SayGM serves both through their native APIs on a single key, so simple tasks can go to GPT-6.1 Sol and hard ones to GPT-5.6 Terra, or both can run in a cascade model.

§ 05