How Five AI Coding Agents Compare on Cost (2026)

AI coding agents have different pricing models, token costs, and session behaviors. This article provides current pricing data for the five agents Styrby supports, estimates typical session costs, and explains the variables that affect your monthly bill.

Per-Token Pricing (March 2026)

All prices are per million tokens. These change frequently, so verify against each provider's pricing page before making decisions.

Model	Input (per 1M)	Output (per 1M)	Cache Read (per 1M)
Claude Opus 4	$15.00	$75.00	$1.50
Claude Sonnet 4	$3.00	$15.00	$0.30
Claude Haiku 3.5	$0.80	$4.00	$0.08
GPT-4o	$2.50	$10.00	$1.25
Gemini 2.5 Pro	$1.25	$10.00	N/A

Typical Session Costs

A "session" means different things for different workflows. Here are realistic estimates based on common usage patterns:

Short Task (Bug Fix, 15 Minutes)

Input: ~20K tokens (code context + prompt). Output: ~5K tokens (fix + explanation). With Claude Sonnet 4, that is roughly $0.06 for input and $0.08 for output. Total: about $0.14 per short session.

Medium Task (Feature Implementation, 1 Hour)

Input: ~100K tokens (larger context, multiple turns). Output: ~30K tokens. With Claude Sonnet 4: $0.30 input + $0.45 output = $0.75. With Opus 4: $1.50 input + $2.25 output = $3.75. That is a 5x difference for the same task. Model selection matters more than anything else you can control.

Long Session (Architecture Work, 4+ Hours)

Input: ~500K tokens (repeated context, many iterations). Output: ~150K tokens. With Sonnet 4: $1.50 + $2.25 = $3.75. With Opus 4: $7.50 + $11.25 = $18.75. Long sessions with expensive models add up fast.

The Cache Token Factor

Cache tokens significantly reduce costs for repeated context. When you send the same codebase context in multiple turns, the provider can serve it from cache at a fraction of the input price.

Claude Sonnet 4 charges $0.30 per million cache read tokens vs. $3.00 for fresh input. That is a 10x reduction. In a multi-turn session where 80% of context is repeated, your effective input cost drops substantially. This is why a 100K-token session does not cost 100K times the per-token rate. Most of those tokens are cached after the first turn.

Monthly Cost Estimates

Usage Pattern	Sessions/Day	Sonnet 4/mo	Opus 4/mo	GPT-4o/mo
Light (hobby)	1-2	$15-30	$75-150	$20-40
Moderate (full-time)	5-8	$75-120	$375-600	$100-160
Heavy (power user)	10+	$150-300	$750-1500	$200-400

Hidden Cost Multipliers

Several factors inflate costs beyond the base token math:

Retry loops. When an agent produces code that fails tests and retries automatically, you pay for both the failed attempt and the retry. Three retries triple the output cost.
Large context windows. Sending your entire codebase as context on every turn is expensive. Be selective about what context you provide.
Model selection. Using Opus for tasks that Sonnet handles well is the single biggest cost mistake. Use Opus for architecture decisions and complex debugging. Use Sonnet for implementation work.

How Styrby Helps With Cost Visibility

The challenge with multi-agent usage is that costs are spread across different billing dashboards. Styrby aggregates token costs from all connected agents into a single view with daily, weekly, and monthly totals. Budget alerts let you set thresholds per agent or globally. Session tags let you label sessions by client or project for filtering.

This is not a sales pitch. The same information is available by checking each provider's billing page individually. Styrby just consolidates it. If you use a single agent, the provider's own dashboard is fine.