Gantt, link bar chart, milestone chart

Example project: part of a house project (weeks).

Gantt chart

A Gantt chart shows every activity as a bar against a calendar scale and records progress inside the bar. It is used to compare planned and actual progress. Here = shows work done up to week 6 and # the work still to do.

                 0   4   8   12  16 (wk)
                +----------------
A Site clearing |=     |         
B Excavation    | ==   |         
C Foundation    |   ===|         
D Plinth beam   |      ##        
E Walls+columns |      | #####   
F Roof slab     |      |      ###
                +----------------
                       ^ status (wk 6)

At week 6, A, B and C are done, D is just starting, and E and F have not yet started.

Linked (link) bar chart

A bar chart in which arrows or links join the finish of a predecessor to the start of its successor. It shows the dependence among the activities. In the figure > shows that the next activity starts when the previous one finishes.

                 0   4   8   12  16  (wk)
                +----------------
A Site clearing |#>              
B Excavation    | ##>            
C Foundation    |   ###>         
D Plinth beam   |      ##>       
E Walls+columns |        #####>  
F Roof slab     |             ###
                +----------------

Milestone chart

It shows only the key events (milestones) of the project on the time scale, such as site ready, foundation complete and structure complete. It is used by top management to see the major targets and to compare planned and forecast dates.

                       0   4   8   12  16 (wk)
                      +----------------
M1 Site ready         |*
M2 Foundation done    |     *
M3 Structure done     |            *
                      +----------------