Lighting Calculator

SWMBO has graciously allowed me to plan a new shed/garage. Can anyone tell me where I can find a formula/plan to work out the number and location of fluorescent light fittings (I'm thinking 4 ft double fluoro tubes) needed for good even light in the new shed? I'm assuming that there is some method of calculating the lights required for a space of given dimensions.
Of course, the catch is SWMBO gets a LARGE new room above the shed/ garage (memo to self: must remember to always refer to it as The Shed ) which she has indicated will be lit with downlights. Does anyone have a similar calculator/planner for downlights in a room of given dimensions.

Many thanks

Mog4


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