The true cost of running AI locally
A machine that runs AI models at home is a large one-off purchase. A plan is a monthly bill that never ends. This sets one against the other over the years you would keep the machine, counting electricity and what the machine would sell for afterwards, and tells you what a plan has to cost before buying comes out ahead. Pick a machine and a plan, or type your own figures.
The true cost of running AI locally
Over 3 years, working 4 hours a day
$3,771
- Price of the machine
- $5,499
- Electricity
- $197
- Plan you’d keep anyway
- $0
- Resale value
- −$1,925
- The plan over the same time
- $3,600
- Plan price needed to break even
- $105 a month
Keeping the plan costs $171 less over 3 years.
The machine only comes out ahead if it replaces a plan costing more than $105 a month.
Year by year
The running total spent on each. The machine starts with its full price and falls in the last year, when it is sold. The plan climbs by the same amount every month.
Show the figures for every year
| Year | Machine, this year | Plan, this year | Machine, total so far | Plan, total so far |
|---|---|---|---|---|
| 1 | $5,565 | $1,200 | $5,565 | $1,200 |
| 2 | $66 | $1,200 | $5,630 | $2,400 |
| 3 | -$1,859 | $1,200 | $3,771 | $3,600 |
How this is worked out
What the machine costs
- The price, paid up front.
- Electricity. The power it draws while working, times the hours a day it works, times your electricity price. Power used while idle is left out.
- Any plan you keep. If you would still pay for a cheaper plan alongside the machine, that goes on this side.
- Resale. What the machine sells for at the end is taken off.
What the plan costs
The monthly price, times twelve, for each year, rising by the yearly increase if you set one.
The plan price needed to break even
This is everything the machine costs, spread over the months you would keep it. If the plan you would drop costs more than this, the machine wins. If it costs less, the plan wins. It is the most useful number on the label, because it does not depend on which plan you picked.
The part no calculator can settle
A machine and a plan do not give you the same thing. The plans run their makers’ largest models in a data centre. A machine at home runs open models that fit in its memory, and those are smaller. For some work the difference does not matter. For some it decides everything. The calculator compares the money and leaves that judgment to you, so try an open model on the kind of work you do before buying anything.
Memory is the limit that matters most. A model has to fit in the machine’s memory to run at a usable speed, so 16GB or 24GB holds only small models, while 96GB or more holds the largest ones people commonly run at home. On a PC, the memory that counts is on the graphics card.
What is not counted
- Your time setting it up and keeping it working.
- Everything else the machine can do. A Mac is still a computer when it is not running a model.
- Usage limits. Plans cap how much you can use them; your own machine does not.
- Privacy and working offline. On your own machine nothing leaves the room, which for some people is the whole reason to buy one.
- Sales tax, and interest the money could have earned.
When buying does come out ahead
Buying wins when the plan it replaces is expensive, when you keep the machine for many years, and when it holds its value. It loses when you would keep paying for a plan anyway, which is common: add that under “Plan you’d keep anyway” and see how the answer moves.
Where the starting figures come from
Prices were checked on October 10, 2026 and change often. Every figure can be typed over, so use today’s price if it has moved.
Plans. US monthly prices from each company’s own pricing page: Claude, ChatGPT and Grok. Claude Max costs $100 for five times the usage of Pro, or $200 for twenty times. ChatGPT Pro is sold in three tiers that start at $100, and the dearer two are not listed here. Annual billing is usually a little cheaper.
Macs. Apple’s starting prices for the Mac mini with M6 and M5 Pro, and the Mac Studio with M5 Ultra, each with the smallest memory offered. More memory costs more.
Nvidia DGX Spark. $4,699, after a rise from its $3,999 launch price reported in February 2026.
PC with an RTX 5090. The least certain figure here. The card launched at $1,999, but a shortage has pushed it far higher: listings in October 2026 started around $6,000 and ran to about $8,000 for the card alone. The calculator uses $8,500 for a complete PC, allowing about $1,500 for everything else. Check today’s price before relying on it.
Electricity. The US Energy Information Administration expects the average home price to be about 18 cents per kilowatt-hour in 2026.
Our assumptions. The power each machine draws, the 4 hours a day, the3 years and the 35% resale value are estimates, not published figures. On the starting figures the machine costs $5,499 and the plan $100 a month.