The Absurd Math of $20 AI Coding Subs: Codex vs. Claude Code

Hey everyone, so I was basically curious what $20/month actually buys you, so I dug into my local session logs (~/.codex and ~/.claude) to calculate the exact token volume, caching hits, and real API value of both tools. The difference in how much compute you actually get is wild. Full Breakdown: Claude Opus 5 vs GPT 5.6 Sol both measured in Medium reasoning tier. The biggest difference isn't just the size of the limits, but how they are paced. - Codex (7-day rolling limit): You get roughly 139M tokens a week. If you go on a massive coding bender and burn through that in a single day, you are locked out for the next 6 days. ~100M tokens is your entire weekly tank. - Claude Code (5-hour rolling limit): You get roughly 98M tokens every 5 hours. If you hit the limit, you just take a coffee break, it resets, and you can go again. ~100M tokens is just a pit stop. The Real API Value (What you're actually getting) Both companies are heavily subsidizing these $20 subscriptions. If we price out the raw tokens using their official API rates (Opus 5 and GPT-5.6, factoring in caching discounts), the monthly ROI looks like this: - Codex (20/mo): Delivers ~600 million tokens a month. If you paid for this via API, it would cost roughly $850 (a 42x ROI). - Claude Code (20/mo standard): Delivers ~2.8 billion tokens a month. API equivalent: ~$2,400 (a 120x ROI). - Claude Code (with 50% promo boost): Delivers 4.2 billion tokens a month. API equivalent: $3,600+ (a 180x ROI). (Note: Even if you do massive cache-looping on Codex to push it to ~1.2B tokens a month, Claude still gives you more than double the volume). Pennies on the Dollar Because the subsidies are so massive (97-99% off raw API rates), you are effectively paying fractions of a cent per million tokens. - On Claude, doing a 5-hour marathon sprint (~98M tokens) costs you about $0.70 out of your subscription. - On Codex, burning your entire weekly allowance (~139M tokens) costs you about $4.65. The TL;DR Both tools are incredible deals compared to paying for raw API keys. However, Claude Code gives you nearly 5x the total compute (2.8B vs 0.6B monthly tokens). Combine that with a forgiving 5-hour reset window instead of Codex's brutal 7-day penalty box, and Claude is by far the most generous environment for heavy developers right now.