The Speed percentage on a building determines how quickly it produces items. 200% means a building works twice as fast, 1000% is ten times as fast.
You can find all the various speed boosts for a building by left-clicking on it and looking at the Speed stat shown above.
Note that the percentage shown is not simply adding up the listed bonuses, this page details how the various bonuses are calculated.
There are two categories of speed boosts, Global and Per-Building, and those two categories are multiplied together to give the final result.
|300%||Happiness Production Bonus||Increase Happiness by selling goods to Houses. Varies based on supply.|
|25%||Global Production Bonus||Can be increased by researching Production Speed with the OmniTemple.|
|25%||Extra Worker||With 5 total workers a the bonus reaches 100%. Farms, Mines, Foresters and Fisheries get more. (Note 1)|
|50%||Steam Power||Requires Steam Pipes connected to a Steam Generator.|
|40%||Omnistone Upgrade||Each level increases this bonus by 40%. (Note 2)|
|100%||Element Booster||Requires a supply of charged element crystals to maintain the bonus.|
To calculate a buildings productivity, add up all the values in the Global table, add up all the values in the Per-Building table and multiply those together.
Global: 100% Base Productivity + 200% Happiness + 50% Global Production Bonus = 250%
Per-Building: 100% Base Boost + 75% (3 Extra Workers) + 50% Steam Power = 225%
Final Productivity is 250% x 225% = 563%
1: The first worker does not count as an extra worker. So 5 total workers give a max 100% boost (25% x 4 Extra Workers) . Farms, Mines, Foresters and Fisheries give 100% per Extra Worker instead of 25%. In addition, Farms, Mines and Foresters can have 10 total workers for a max boost of 900%.
2: OmniStone Upgrades start at 40% per level invested in a building. But researching "OmniUpgrade Power" with the OmniTemple adds another 40% per level. This means if you have "Lv 3 OmniUpgrade Power" researched, each level on "Omnistone Upgrade" gives you 160%.