Local AI vs ChatGPT and Claude subscriptions: cost calculator
Short answer
For one person using a single chat subscription at about $20 a month, such as ChatGPT Plus or Claude Pro, a Mac bought only for local AI rarely pays for itself on cost alone. Local AI wins when you would otherwise pay for several subscriptions or heavy API usage, when you need privacy or offline use, or when you already own a Mac with enough memory.
Running AI on your own Mac has no monthly bill, but the hardware isn't free. Here is how to work out whether it saves you money.
Calculator
The formula
Monthly cost of local AI = (Mac price − resale value after you're done) ÷ months you'll keep it + electricity per month
Break-even is when that number falls below what you would otherwise spend each month on cloud AI.
Worked example
Say you buy a Mac Studio for $3,000, keep it for four years (48 months) and sell it for $1,000.
- Hardware: ($3,000 − $1,000) ÷ 48 = $41.67 a month
- Electricity: 150 W × 4 hours a day × 30 days = 18 kWh, at $0.17 per kWh = about $3 a month
- Total: about $45 a month
Against one $20-a-month chat subscription, local AI loses on cost alone. Against two or three subscriptions, or $50 or more a month of API usage for coding tools and automations, it starts to win, and the Mac is also your everyday computer.
When local AI makes financial sense
- You already own a capable Mac. Then the extra cost is close to zero.
- You run lots of tokens. Automations, agents and coding assistants can run up API bills quickly. A local model has no per-use charge.
- You'd pay for several tools. Local models can stand in for several narrow subscriptions at once.
- Privacy has value to you. Client documents, health or financial records can stay on your machine.
When it doesn't
- You use AI lightly, a few questions a day.
- You need the very strongest models for hard work. The top cloud models are still ahead of what runs at home.
- You'd buy a Mac with far more memory than you need just for AI.
A practical middle path
Many people use both: a local model for everyday, private and high-volume work, and a cloud subscription for the hardest problems. Start with what your current Mac can run (see your first local LLM with Ollama), then decide whether a bigger machine is worth it using which Mac to buy for local AI.
Frequently asked questions
How much electricity does a Mac use running a local model?
Far less than a PC with a large graphics card. Apple Silicon Macs draw from a few watts at idle to a couple of hundred watts at full load on the biggest chips, so a few hours of daily use typically costs a few dollars a month. Check the exact figure for your model on Apple's power consumption page.
Are local models as good as ChatGPT or Claude?
The best cloud models are still ahead, especially on hard reasoning and long tasks. Open models you can run locally are good enough for many everyday jobs, such as drafting, summarizing, coding help and private document search.