SOP: Assign Durations in Microsoft Project

Purpose

Assign accurate task durations so the project schedule is realistic, balanced, and achievable.

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Step 1: Create the Task List

Before assigning durations, create all project tasks.

Example:

ID	Task Name
1	Site Survey
2	Excavation
3	Rebar Installation
4	Concrete Pouring
5	Brickwork
6	Painting

Rule:

• One task = One clear activity.

• Do not combine multiple activities into one task.

❌ "Excavation + Rebar + Concrete"

✅ "Excavation"
✅ "Rebar Installation"
✅ "Concrete Pouring"

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Step 2: Estimate Work Quantity

Determine how much work must be completed.

Example:

Task	Quantity
Excavation	50 m³
Brickwork	100 m²
Painting	500 m²

Duration should be based on quantity, not guessing.

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Step 3: Determine Productivity Rate

Find how much work the crew can complete per day.

Example:

Task	Daily Productivity
Excavation	10 m³/day
Brickwork	20 m²/day
Painting	100 m²/day

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Step 4: Calculate Duration

Formula:

\text{Duration} = \frac{\text{Work Quantity}}{\text{Daily Productivity}}

Example:

Excavation:

• Quantity = 50 m³

• Productivity = 10 m³/day

Duration:

50 ÷ 10 = 5 Days

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Step 5: Enter Duration in Microsoft Project

In the Duration column, enter:

Task	Duration
Site Survey	2d
Excavation	5d
Rebar Installation	3d
Concrete Pouring	1d
Brickwork	5d
Painting	5d

Common Units:

Unit	Meaning
m	Minutes
h	Hours
d	Days
w	Weeks
mo	Months

Examples:

• 8h = 8 Hours

• 5d = 5 Days

• 2w = 2 Weeks

• 1mo = 1 Month

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Step 6: Use Milestones Correctly

Milestones have no duration.

Enter:

0d

Examples:

Task	Duration
Contract Signed	0d
Design Approved	0d
Project Handover	0d

Remember:

• Tasks = Work

• Milestones = Events

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Step 7: Review Resource Capacity

Check whether the duration is achievable.

Example:

If Brickwork requires:

• 100 m²

• Crew productivity = 20 m²/day

Then:

• 5 Days = Realistic

But:

• 2 Days = Unrealistic

Always verify with actual site productivity.

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Step 8: Add Contingency When Necessary

For risky activities, add reasonable buffer.

Examples:

Task	Normal	Planned
Excavation	5d	6d
Painting	5d	6d

Reasons:

• Rain

• Material delays

• Equipment breakdown

• Labor shortages

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Step 9: Check the Schedule Logic

After entering durations:

1. Create task relationships (FS, SS, FF, SF).

2. Review the Gantt Chart.

3. Look for unrealistic durations.

4. Verify Critical Path activities.

5. Adjust durations if necessary.

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Best Practice for Construction Projects

1. Define task clearly.

2. Measure work quantity.

3. Calculate productivity.

4. Assign realistic duration.

5. Link tasks correctly.

6. Review resource availability.

7. Add contingency for risks.

8. Update actual durations during construction.

Golden Rule

Do not guess task durations.

Use:

Quantity + Productivity + Experience = Accurate Duration

This creates a schedule that is easier to manage, easier to track, and more likely to finish on time.

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