Estimates#

Note

Spanish Term: Estimación

Understanding estimates (progress payments) in Construbot.

What is an Estimate?#

An Estimate (Spanish: Estimación) is a progress payment request for completed work on a construction project. Estimates document:

  • Work completed during a specific period

  • Quantities of each concept (line item) executed

  • Payment amount owed for the period

  • Cumulative progress tracking

Model: construbot.proyectos.models.Estimate

Key Concept: Estimates are tied to contracts and track incremental billing as work progresses. Each estimate builds upon previous estimates to show cumulative project completion.

Estimate Components#

Basic Information#

Required fields:

  • Contract (contrato) - The parent contract being billed

  • Estimate Number (consecutive number) - Sequential identifier

  • Period Start Date (fecha_inicio_estimado)

  • Period End Date (fecha_final_estimado)

  • Total Amount (monto) - Calculated from line items

Optional fields:

  • Notes (notas) - Internal notes about the estimate

  • Status - Draft, submitted, approved, paid

  • Approval Date

  • Payment Date

Line Items (EstimateLineItems)#

Each estimate contains multiple line items tracking individual concept progress:

  • Concept (concepto) - Reference to catalog concept

  • Quantity This Period (cantidad_estimada) - Work completed this period

  • Cumulative Quantity (cantidad_acumulada) - Total work to date

  • Unit Price (precio_unitario) - From contract concept

  • Subtotal (subtotal) - Quantity × Unit Price

Related Model: construbot.proyectos.models.EstimateLineItem

Financial Calculations#

Estimate Amount Calculation#

The estimate total is calculated as:

Subtotal = Sum of (Quantity This Period × Unit Price) for all line items

Retentions = Subtotal × Retention Percentage(s)

Estimate Total = Subtotal - Retentions

Amount to Pay = Estimate Total - Previous Balance (if applicable)

Example:

Line Items:
- Excavation: 150 m³ × $200/m³ = $30,000
- Concrete: 80 m³ × $1,500/m³ = $120,000
- Rebar: 2,500 kg × $15/kg = $37,500

Subtotal: $187,500
Retention (10%): -$18,750
Estimate Total: $168,750

Cumulative Tracking#

Construbot automatically tracks cumulative quantities:

  1. Previous Estimates: Sum of all prior estimate quantities

  2. This Estimate: New work completed

  3. Cumulative Total: Running total of all work to date

  4. Remaining: Contract quantity - Cumulative total

This ensures you never over-bill a contract concept.

Retentions (Withholdings)#

Retentions can be applied to estimates:

  • Flat percentage: 10% retention on all work

  • Multiple retentions: Different percentages for different purposes (warranty, performance)

  • Retention release: Held until contract completion or milestones

See Retentions for detailed information.

Creating an Estimate#

Step 1: Access Contract#

  1. Navigate to Proyectos → Contratos

  2. Select the contract you want to bill

  3. Click “Create Estimate” or “Nueva Estimación”

Step 2: Set Estimate Period#

Period Start: 2024-01-01
Period End: 2024-01-31
Estimate Number: Auto-assigned (e.g., Estimate #3)

Step 3: Add Line Items#

For each concept with work completed:

  1. Select the concept from contract catalog

  2. Enter Quantity This Period (work completed)

  3. System calculates: - Cumulative quantity - Subtotal (quantity × unit price) - Warnings if exceeding contract quantity

Example Entry:

Concept: Excavation (Contract Qty: 500 m³)
Previous Estimates: 200 m³
This Estimate: 150 m³
Cumulative: 350 m³
Remaining: 150 m³

Unit Price: $200/m³
Subtotal: $30,000

Step 4: Review Totals#

Before saving, review:

  • Subtotal: Sum of all line items

  • Retentions: Applied percentages

  • Estimate Total: Amount to be paid

  • Cumulative Progress: Overall project completion

Step 5: Save and Generate Documents#

  1. Click “Save” or “Guardar”

  2. Generate PDF estimate document

  3. Submit for approval (if workflow configured)

  4. Track payment status

Estimate Workflow#

Typical Process#

  1. Draft: Initial creation, can be edited

  2. Submitted: Sent to client for review

  3. Under Review: Client reviewing estimate

  4. Approved: Client approved, ready for payment

  5. Paid: Payment received and recorded

Workflow Configuration: May vary by company and contract type.

Revisions and Corrections#

If an estimate needs correction:

Option 1: Edit Draft

  • If status is still “Draft”, edit directly

  • Update line item quantities as needed

Option 2: Create Adjustment

  • If estimate is approved, create a new estimate

  • Use negative quantities to reverse errors

  • Add corrected quantities in same or next estimate

Best Practice: Add notes explaining any adjustments for audit trail.

Hierarchical Contracts#

For subcontracts using hierarchical structure:

Parent Contract Estimate:

  • Parent estimate includes own work + subcontract estimates

  • Subcontract estimates roll up automatically

  • System prevents double-counting

Subcontract Estimate:

  • Created independently for subcontractor work

  • Linked to parent contract estimate

  • Separate billing and payment tracking

See Projects & Contracts for hierarchy details.

Best Practices#

1. Regular billing cycles:

GOOD: Weekly or monthly estimates with consistent periods
BAD: Irregular estimates with gaps or overlaps

2. Document justification:

Add notes explaining: - Unusual quantities - Zero-quantity periods (weather delays, etc.) - Adjustments or corrections

3. Review cumulative totals:

Before submitting, verify: - No concepts exceed contract quantity - Cumulative percentages make sense - Previous estimates are correctly summed

4. Coordinate with site progress:

  • Estimates should reflect actual completed work

  • Use site photos or daily reports as backup

  • Don’t estimate work not yet performed

5. Track payment timing:

  • Record when estimate submitted

  • Follow up on approvals

  • Document payment receipt

Reporting and Analysis#

Estimate Reports#

Available reports:

  • Estimate Summary: Single estimate with all line items

  • Contract Progress: All estimates for a contract showing cumulative progress

  • Payment Schedule: Estimate amounts vs. payment dates

  • Retention Tracking: Retained amounts and releases

Export Options: PDF, Excel

Financial Metrics#

Track project health:

  • Billing Rate: Actual billed vs. planned

  • Payment Lag: Time from estimate submission to payment

  • Retention Balance: Total retained amounts

  • Completion Percentage: Cumulative quantities vs. contract quantities

Common Scenarios#

Scenario 1: First Estimate#

Setup:

  • New contract with 10 concepts

  • Work started, first month completed

  • 3 concepts have progress

Process:

  1. Create Estimate #1 for Month 1

  2. Add 3 line items with quantities

  3. Review subtotal and retentions

  4. Generate PDF and submit

Result: Establishes baseline for cumulative tracking.

Scenario 2: Zero-Work Period#

Situation: Weather delay, no work completed in period

Options:

  1. Skip estimate: Don’t create estimate for period (creates gap in numbering)

  2. Zero estimate: Create estimate with explanation in notes

Recommendation: Create zero estimate with notes explaining delay for complete audit trail.

Scenario 3: Over-Billing Prevention#

Situation: Trying to bill 200 m³ but only 150 m³ remain on contract

System Behavior:

  • Warning displayed when quantity exceeds remaining

  • Can still save if justified (change orders, variations)

  • Flags for review

Resolution:

  • Adjust quantity to 150 m³, or

  • Create change order to increase contract quantity first

Troubleshooting#

Can’t create estimate:

  • Verify contract has concepts in catalog

  • Check contract status is active

  • Confirm user has permission level (Coordinador or higher)

Quantities not calculating:

  • Ensure unit prices are set on contract concepts

  • Verify previous estimates are saved and approved

  • Check for database sync issues (rare)

Retentions incorrect:

  • Review retention configuration on contract

  • Verify retention percentages are current

  • Check if retentions should apply to this estimate type

PDF generation fails:

  • Verify template files exist

  • Check media storage permissions

  • Review error logs for specific issue

See Also#