बजेट अॅट कंप्लीशन फॉर्म्युला (BAC फॉर्म्युला)

बजेट अॅट कंप्लीशन (BAC) सूत्र हा Earned Value Management चा पाया आहे. तो सर्व प्रकल्प कामांसाठी एकूण मंजूर बजेट परिभाषित करतो. PMBOK 6 व्या आवृत्तीनुसार (पृ.263), BAC सूत्र खालीलप्रमाणे आहे:

थोडक्यात: प्रत्येक वर्क पॅकेज, खर्च श्रेणी आणि आकस्मिक राखीव (contingency reserve) यांचा अंदाज लावला जातो आणि बेरीज केली जाते. एकूण बेरीज तुमचा BAC आहे. एकदा बेसलाइनवर मंजूर झाल्यावर, तो निश्चित असतो — खर्च वाढल्यास BAC बदलत नाही. फक्त Estimate at Completion (EAC) बदलते.

EVM च्या संदर्भात BAC सूत्र

बजेट अॅट कंप्लीशन सूत्र थेट इतर प्रत्येक EVM मेट्रिकवर परिणाम करते:

चुकीचा BAC प्रत्येक पुढील EVM मेट्रिकला अविश्वसनीय बनवतो. BAC सूत्र योग्यरित्या मिळवणे ही प्रकल्प खर्च व्यवस्थापनातील सर्वात महत्त्वाची पायरी आहे.

BAC ची गणना करण्याच्या 5 पद्धती

BAC तयार करण्यासाठी कोणतेही एक अल्गोरिदम नाही. PMBOK विविध अंदाज पद्धती परिभाषित करते, प्रत्येक प्रकल्पाच्या व्याख्येच्या भिन्न स्तरासाठी उपयुक्त आहे:

1. बॉटम-अप अंदाज (सर्वात अचूक)

प्रत्येक वैयक्तिक वर्क पॅकेजचा अंदाज लावा, नंतर सर्व अंदाजांची बेरीज करा. अचूकता: ±5–10%. यासाठी विस्तृत व्याप्ती व्याख्या आवश्यक आहे. हा दृष्टिकोन आमच्या BAC Builder टॅब मध्ये वापरला जातो.

2. समान अंदाज (Analogous)

सुरुवातीचा बिंदू म्हणून तुलना करण्यायोग्य पूर्ण झालेल्या प्रकल्पाचा डेटा वापरा. अचूकता: ±25–75%. जलद परंतु संबंधित ऐतिहासिक डेटा असण्यावर अवलंबून आहे. सुरुवातीच्या टप्प्यातील बजेटसाठी सर्वोत्तम.

3. पॅरामेट्रिक अंदाज

प्रकल्प व्याप्ती आणि एकक खर्च यामधील सांख्यिकीय संबंधावरून खर्च काढा. अचूकता: ±10–20%. बांधकाम (खर्च/m²), सॉफ्टवेअर ($खर्च/फंक्शन पॉइंट), आणि उत्पादन मध्ये सामान्य.

4. तीन-बिंदू अंदाज (PERT)

संभाव्यतेवर आधारित अंदाज तयार करण्यासाठी तीन परिस्थितींचे वजन करा. PERT वेळापत्रक आणि खर्चाच्या अनिश्चिततेचा विचार करतो, ज्यामुळे तो सिंगल-पॉइंट अंदाजापेक्षा अधिक विश्वसनीय बनतो.

5. तज्ञांचा निर्णय

जेव्हा कोणताही तुलनात्मक डेटा अस्तित्वात नसतो तेव्हा पात्र विषय तज्ञांचा सल्ला घ्या. वरीलपैकी कोणत्याही पद्धतीसोबत एकत्रित. अचूकता पूर्णपणे तज्ञांच्या अनुभवावर अवलंबून असते.

सोडवलेले उदाहरण: BAC सूत्र लागू करणे

एका कंपनीने ऑफिस नूतनीकरण प्रकल्पाचे नियोजन केले आहे. प्रकल्प व्यवस्थापक प्रत्येक वर्क पॅकेजसाठी बॉटम-अप अंदाज लावतो:

हा BAC आहे: $990,000. व्यवस्थापन राखीव ($50,000) स्वतंत्रपणे ठेवले जाते आणि BAC सूत्राचा भाग नाही. जर चौथ्या महिन्यापर्यंत 38% कामासाठी $420,000 खर्च झाला असेल, तर EVM मेट्रिक्स असे असतील:

• AC = $420,000
• EV = 38% × $990,000 = $376,200
• CPI = $376,200 / $420,000 = 0.896 (बजेटपेक्षा जास्त)
• EAC = $990,000 / 0.896 =
  Budget at Completion Calculator · April 2026 · 6 min read

  Budget at Completion Formula (BAC Formula)

  The Budget at Completion (BAC) formula is the foundation of Earned Value Management. It defines the total approved budget for all project work. Per PMBOK 6th Edition (p.263), the BAC formula is:

  BAC = Sum of all budgets established for the work to be performed

  In plain terms: every work package, cost category, and contingency reserve is estimated and summed. The total is your BAC. Once approved at baseline, it is fixed — BAC does not change when costs overrun. Only the Estimate at Completion (EAC) changes.

  BAC Formula in Context of EVM

  The Budget at Completion formula feeds directly into every other EVM metric:

  Metric	Uses BAC?	Formula
  Planned Value (PV)	✓	% Planned × BAC
  Earned Value (EV)	✓	% Complete × BAC
  CPI	Indirectly	EV / AC
  EAC (typical)	✓	BAC / CPI
  VAC	✓	BAC − EAC
  TCPI	✓	(BAC − EV) / (BAC − AC)

  An inaccurate BAC makes every downstream EVM metric unreliable. Getting the BAC formula right is the most important step in project cost management.

  5 Methods to Calculate BAC

  There is no single algorithm for building BAC. PMBOK defines several estimation approaches, each suited to a different level of project definition:

  1. Bottom-Up Estimation (Most Accurate)

  BAC = Σ (cost of each work package)

  Estimate every individual work package, then sum all estimates. Accuracy: ±5–10%. Requires detailed scope definition. This is the approach used in our BAC Builder tab.

  2. Analogous Estimation

  BAC = Actual cost of similar past project × adjustment factor

  Use data from a comparable completed project as the starting point. Accuracy: ±25–75%. Fast but relies on having relevant historical data. Best for early-stage budgets.

  3. Parametric Estimation

  BAC = unit cost × quantity (e.g. $/m² × project area)

  Derive cost from a statistical relationship between project scope and unit cost. Accuracy: ±10–20%. Common in construction (cost/m²), software ($cost/function point), and manufacturing.

  4. Three-Point Estimation (PERT)

  BAC = (Optimistic + 4 × Most Likely + Pessimistic) / 6

  Weight three scenarios to produce a probability-weighted estimate. PERT accounts for schedule and cost uncertainty, making it more reliable than a single-point estimate.

  5. Expert Judgement

  Consult qualified subject matter experts when no comparable data exists. Combined with any of the above methods. Accuracy depends entirely on expert experience.

  Worked Example: Applying the BAC Formula

  A company is planning an office renovation project. The project manager applies bottom-up estimation to each work package:

  Work Package	Budget
  Demolition & Site Prep	$80,000
  Structural Work	$220,000
  Electrical & Plumbing	$180,000
  Interior Fit-Out	$340,000
  Project Management	$80,000
  Contingency Reserve (10%)	$90,000
  BAC (Cost Baseline)	$990,000
  Management Reserve (5%)	$50,000
  Total Project Budget	$1,040,000

  This is the BAC: $990,000. The management reserve ($50,000) is held separately and is NOT part of the BAC formula. If by month 4 the project has spent $420,000 on 38% of the work, the EVM metrics become:

  • AC = $420,000
  • EV = 38% × $990,000 = $376,200
  • CPI = $376,200 / $420,000 = 0.896 (over budget)
  • EAC = $990,000 / 0.896 = $1,104,911 (projected overrun of $114,911)

  What BAC Does NOT Include

  Key Rule: BAC = Cost Baseline = Direct Costs + Indirect Costs + Contingency Reserve.
  BAC does not include Management Reserve (held by management for unknown-unknown risks).
  BAC + Management Reserve = Total Project Budget.

  Why BAC Must Never Change Mid-Project

  A cost overrun does NOT change BAC. If your project overspends, you track this through:

  • CV (Cost Variance) = EV − AC → shows current overrun amount
  • EAC → shows revised total cost forecast
  • VAC (Variance at Completion) = BAC − EAC → shows projected final overrun

  If the project scope formally changes (approved change request), only then can the BAC be re-baselined. This is called a budget revision and requires formal change control.

  → Build Your BAC with Our Free Calculator ,104,911 (अंदाजित
  Budget at Completion Calculator · April 2026 · 6 min read

  Budget at Completion Formula (BAC Formula)

  The Budget at Completion (BAC) formula is the foundation of Earned Value Management. It defines the total approved budget for all project work. Per PMBOK 6th Edition (p.263), the BAC formula is:

  BAC = Sum of all budgets established for the work to be performed

  In plain terms: every work package, cost category, and contingency reserve is estimated and summed. The total is your BAC. Once approved at baseline, it is fixed — BAC does not change when costs overrun. Only the Estimate at Completion (EAC) changes.

  BAC Formula in Context of EVM

  The Budget at Completion formula feeds directly into every other EVM metric:

  Metric	Uses BAC?	Formula
  Planned Value (PV)	✓	% Planned × BAC
  Earned Value (EV)	✓	% Complete × BAC
  CPI	Indirectly	EV / AC
  EAC (typical)	✓	BAC / CPI
  VAC	✓	BAC − EAC
  TCPI	✓	(BAC − EV) / (BAC − AC)

  An inaccurate BAC makes every downstream EVM metric unreliable. Getting the BAC formula right is the most important step in project cost management.

  5 Methods to Calculate BAC

  There is no single algorithm for building BAC. PMBOK defines several estimation approaches, each suited to a different level of project definition:

  1. Bottom-Up Estimation (Most Accurate)

  BAC = Σ (cost of each work package)

  Estimate every individual work package, then sum all estimates. Accuracy: ±5–10%. Requires detailed scope definition. This is the approach used in our BAC Builder tab.

  2. Analogous Estimation

  BAC = Actual cost of similar past project × adjustment factor

  Use data from a comparable completed project as the starting point. Accuracy: ±25–75%. Fast but relies on having relevant historical data. Best for early-stage budgets.

  3. Parametric Estimation

  BAC = unit cost × quantity (e.g. $/m² × project area)

  Derive cost from a statistical relationship between project scope and unit cost. Accuracy: ±10–20%. Common in construction (cost/m²), software ($cost/function point), and manufacturing.

  4. Three-Point Estimation (PERT)

  BAC = (Optimistic + 4 × Most Likely + Pessimistic) / 6

  Weight three scenarios to produce a probability-weighted estimate. PERT accounts for schedule and cost uncertainty, making it more reliable than a single-point estimate.

  5. Expert Judgement

  Consult qualified subject matter experts when no comparable data exists. Combined with any of the above methods. Accuracy depends entirely on expert experience.

  Worked Example: Applying the BAC Formula

  A company is planning an office renovation project. The project manager applies bottom-up estimation to each work package:

  Work Package	Budget
  Demolition & Site Prep	$80,000
  Structural Work	$220,000
  Electrical & Plumbing	$180,000
  Interior Fit-Out	$340,000
  Project Management	$80,000
  Contingency Reserve (10%)	$90,000
  BAC (Cost Baseline)	$990,000
  Management Reserve (5%)	$50,000
  Total Project Budget	$1,040,000

  This is the BAC: $990,000. The management reserve ($50,000) is held separately and is NOT part of the BAC formula. If by month 4 the project has spent $420,000 on 38% of the work, the EVM metrics become:

  • AC = $420,000
  • EV = 38% × $990,000 = $376,200
  • CPI = $376,200 / $420,000 = 0.896 (over budget)
  • EAC = $990,000 / 0.896 = $1,104,911 (projected overrun of $114,911)

  What BAC Does NOT Include

  Key Rule: BAC = Cost Baseline = Direct Costs + Indirect Costs + Contingency Reserve.
  BAC does not include Management Reserve (held by management for unknown-unknown risks).
  BAC + Management Reserve = Total Project Budget.

  Why BAC Must Never Change Mid-Project

  A cost overrun does NOT change BAC. If your project overspends, you track this through:

  • CV (Cost Variance) = EV − AC → shows current overrun amount
  • EAC → shows revised total cost forecast
  • VAC (Variance at Completion) = BAC − EAC → shows projected final overrun

  If the project scope formally changes (approved change request), only then can the BAC be re-baselined. This is called a budget revision and requires formal change control.

  → Build Your BAC with Our Free Calculator 14,911 ओव्हररन)

BAC मध्ये काय समाविष्ट नसते

प्रकल्पाच्या मध्यभागी BAC का बदलू नये

खर्च वाढल्याने BAC बदलत नाही. जर तुमचा प्रकल्प जास्त खर्च करत असेल, तर तुम्ही याद्वारे त्याचा मागोवा घेता:

• CV (कॉस्ट व्हेरियन्स) = EV − AC → सध्याची जास्त झालेली रक्कम दर्शवते
• EAC → सुधारित एकूण खर्चाचा अंदाज दर्शवते
• VAC (व्हेरियन्स अॅट कंप्लीशन) = BAC − EAC → अंदाजित अंतिम ओव्हररन दर्शवते

जर प्रकल्पाची व्याप्ती औपचारिकपणे बदलली (मंजूर बदल विनंती), तरच BAC री-बेसलाइन केले जाऊ शकते. याला बजेट पुनरावृत्ती (budget revision) म्हणतात आणि यासाठी औपचारिक बदल नियंत्रणाची आवश्यकता असते.