What are light, medium and heavy Cowork tasks?

Light, medium and heavy are the three tiers Microsoft uses to describe how much a Cowork task spends. A light task - a quick question or a small edit - runs around 100 to 300 credits. A medium task - a few steps, some digging, a couple of outputs - around 400 to 700. A heavy task - research, assembly, many steps and a long output - 700 to 2,000 or more. In pounds at pay-as-you-go rates: roughly 80p to £2.40, £3 to £5.50, and £5.50 to £16.

The tiers are useful because they reframe the question. Nobody can intuit what 500 credits means; everyone can tell whether the job they're about to give Cowork is a quick tidy or an afternoon's assembly. Estimate the tier, and the cost follows.

What moves a task up a tier is almost always gathering, not writing. A ten-slide deck from one document is medium; the same deck after Cowork has researched the topic across your files and the web is heavy, because every retrieval step spends credits. Length of output matters far less than people expect.

Microsoft's own default usage figures - the ones this calculator starts from - assume a mix per person per month: mostly light, a fair amount of medium, a few heavy. Where a business's real mix skews heavy, as it does for engineers and researchers, the per-person cost climbs quickly.