Your AI spend has no speed limit.
Microsoft Cowork bills by the credit and ships with no default spending cap. Work out what a task costs, what a month costs, and how long your cap actually lasts.
What a task costs.
What a month costs.
Every figure starts on Microsoft's own defaults, taken from Cowork Frontier customer usage as at 27 May 2026. Change anything you like. Everything recalculates as you type.
Step 1
Who will use Cowork?
Example figures are set for a 20 person business. Overwrite with your own headcount.
- Total users20
Step 2
How many prompts per user, per month?
Microsoft's defaults are shown. Overwrite them once you have a month of your own usage data in the admin centre.
| Role | Light | Medium | Heavy |
|---|---|---|---|
| Corporate | |||
| Customer facing | |||
| Technical | |||
| Managers |
Step 3
How many credits per prompt?
Light: narrow context, lightweight model, one tool call at most, one deliverable. Medium: richer context, capable model, several tool calls, two or more outputs. Heavy: broad context aggregation, high quality model, many tool calls, sustained runtime, many outputs.
Step 4
Price and model assumptions
List price, pay as you go. Prepaid plans cost less per credit.
Rate at 24 July 2026. Update it before quoting sterling.
100% is Microsoft's Opus 4.8 baseline. Drag to 74% to test a 26% saving. Credits count model, context retrieval, tool calls and runtime, so a token saving does not convert one for one. Treat this as a sensitivity test, not a forecast.
Step 5
Cap and burn rate
Pull the real daily figure from the Copilot Credits report in the Microsoft 365 admin centre.
Your intelligence budget
£2,258Estimated cost per month
- Monthly Copilot Credits300,475
- Monthly cost (USD)$3,004.75
- Per user, per month£112.89
- Estimated annual cost£27,094
What a single task costs
| Prompt | Credits | USD | GBP |
|---|---|---|---|
| Light | 125 | $1.25 | £0.94 |
| Medium | 500 | $5.00 | £3.76 |
| Heavy | 1,200 | $12.00 | £9.02 |
This is the number almost nobody in your organisation can quote.
Cap and burn rate
Days the cap lasts
12.5
Cost of the cap
£188
Where every number came from.
Check these before you quote a figure to a client or a board.
Credit price and prepaid plans
$0.01 per Copilot Credit, pay as you go list price. Confirmed by Microsoft's own estimator formula, where the monthly budget equals credits divided by 100.
Prepaid plans carry a lower cost per credit than pay as you go. If you are on a capacity pack or a pre-purchase plan, replace the credit price in Step 4 with your real rate.
Credits per prompt and prompt mix
Light 125, medium 500, heavy 1,200. Microsoft Cowork Frontier customer data as at 27 May 2026.
Prompt mix per persona: corporate 22 / 11 / 5. Customer facing 17 / 13 / 5. Technical 12 / 9 / 14. Managers 13 / 6 / 3. Same Microsoft source.
Model baseline and the efficiency factor
Microsoft's estimates assume Anthropic Opus 4.8. Opus 5 launched on 24 July 2026 at the same price per million tokens, so budgets built on the older baseline are worth re-running.
The efficiency factor is a sensitivity lever, not a forecast. Credits count model, context retrieval, tool calls and runtime, so a token saving does not convert one for one into a credit saving.
Exchange rate and spending limits
GBP/USD 1.3308 on 24 July 2026. Update it before quoting sterling.
Microsoft applies no default spending limits on Cowork. Nothing is capped until an administrator sets a policy.
Sources
Microsoft Customer Cowork Estimator: aka.ms/CustomerCoworkEstimator
Cowork billing: learn.microsoft.com, usage based billing overview
Pay as you go meters: learn.microsoft.com, pay as you go meters
Your own usage: Microsoft 365 admin centre, Reports, Usage, Microsoft 365 Copilot, Credits.
A cap sized for a team, but set at one power user's monthly allowance,
is how a business runs out of thinking mid month.
Figures are directional and for budgeting discussion only. Microsoft's underlying data is aggregated and anonymised from its Cowork Frontier programme, is described by Microsoft as illustrative, and is not guaranteed. Validate against your own tenant's usage before committing a budget. Rebuilt and branded for Diary of a Chief AI Officer. Original model structure by Microsoft. Microsoft, Copilot and Cowork are trademarks of Microsoft Corporation. This tool is independent and unaffiliated.
