Benefit Cost Ratio: Formula, Worked ₹ Crore Example and Check Sheet

• Benefit cost ratio is the present value of benefits divided by the present value of costs. A result above 1.0 means benefits exceed costs, and exactly 1.0 means a net present value of zero.
• The discount rate matters most when benefits arrive late. In our worked example the ratio falls from 1.49 at 4% to 1.12 at 15%.
• A ratio is only as sound as its benefit and cost inputs. The auditor's recomputation of a state irrigation project gave 0.52 against a projected 1.51.
• Before you show a ratio to an approver, run the stress test and the break-even test in this page, and show net present value beside it.

Divide the present value of all benefits by the present value of all costs. Present value converts money received or spent in later years into today's rupees: divide each year's amount by (1 + r) raised to the number of years, where r is the discount rate, the annual rate used to shrink future amounts. The standard formulation uses discounted incremental benefits over discounted incremental costs. "Incremental" means only what the programme changes compared with doing nothing.

At exactly 1.0, present benefits equal present costs, so net present value (NPV, benefits minus costs in today's rupees) is zero.

At a 12% discount rate, our illustrative programme has present benefits of ₹124.95 crore against present costs of ₹103.06 crore, a ratio of 1.21 and an NPV of ₹21.89 crore.

Discounting each line gives these totals, calculated before rounding:

• Present value of capital cost: ₹86.79 crore.
• Present value of operating cost: ₹16.27 crore.
• Present value of benefits: ₹124.95 crore.
• BCR: 124.95 ÷ (86.79 + 16.27) = 1.21.
• NPV: 124.95 − 86.79 − 16.27 = ₹21.89 crore.
• Break-even level: 103.06 ÷ 124.95 = 0.825. Benefits can fall about 17.5% below plan before the ratio reaches 1.0.
• Stress BCR: 0.8 × 124.95 ÷ (1.2 × 86.79 + 16.27) = 99.96 ÷ 120.42 = 0.83.

The programme clears 1.0 on plan and fails it under a modest overrun combined with a modest benefit shortfall.

For this programme, a lot: the ratio falls from 1.49 at 4% to 1.12 at 15%. Capital cost is spent in years 0 and 1, while benefits arrive in years 2 to 5, so higher rates shrink benefits more than costs.

The rates are our test points. For public-sector projects, an assessment published in Economic and Political Weekly estimates India's ideal social discount rate at 3.72% in real terms, after allowing for inflation (Dholakia, Pattanaik and Kumar, EPW, 13 July 2024). A rate quoted in real terms goes with cash flows in constant prices; a nominal rate goes with cash flows that include inflation. Do not mix them.

For a private or corporate programme, use the rate your finance team or funder prescribes. If none exists, show the ratio at three rates, as above, and let the approver see how far the verdict moves. Note that this programme's 8% result of 1.34 looks healthy but fails the stress test at 0.92.

Put operating cost in the denominator or net it off the benefits, but choose one convention and use it for every project you compare. Both versions always land on the same side of 1.0, because benefits exceed capital plus operating cost exactly when benefits less operating cost exceed capital cost. They differ in size.

In our example at 12%, counting operating cost as a cost gives 1.21 and netting it off benefits gives 1.25. At 4% the gap widens to 1.49 against 1.61.

The difference matters when you compare a ratio against a hurdle other than 1.0, or against another project calculated the other way. Funders define benefits and costs differently, so check the definition your approver or funder uses before you compare (Wikipedia, Benefit–cost ratio). State your convention in a footnote under the number.

The ratio falls sharply even though the formula is untouched. The performance audit report of the Comptroller and Auditor General of India (CAG) on the Kaleshwaram lift irrigation project in Telangana, tabled in the Telangana Legislative Assembly in February 2024, recomputed the benefit cost ratio at 0.52 against the 1.51 the state had projected (ThePrint, 16 February 2024; the tabling is also reported by NewsMeter).

At the original cost estimate of ₹81,911 crore the CAG recomputed the ratio at 0.75 against the state's 1.51; at the latest likely cost of ₹1,47,427 crore it falls to 0.52. The reported differences fall into three groups:

• Benefit assumption: the state assumed one TMC (thousand million cubic feet of water) irrigates 17,668 acres; other Telangana projects showed about 10,000 acres per TMC.
• Annual cost assumption: a power tariff of ₹3 a unit was assumed, against ₹6.40 a unit for lift irrigation.
• Overall finding: the CAG found benefits overstated and annual costs understated.
• Cost growth: the project cost estimate rose from ₹81,911 crore to ₹1,47,427 crore.

Separately, on outcomes, only 40,888 acres of command area had been developed by March 2022, against a target of 18.26 lakh acres.

Our arithmetic: re-assessed inputs alone roughly halve the ratio (1.51 to 0.75), and cost growth takes it from 0.75 to 0.52.

Our inference for any programme: each benefit line should carry its owner, its unit rate, its source and the date it was checked. Our benefits realisation page covers how to build that register.

Treat the ratio as one test among four: it is above 1.0, it holds under stress, you know the break-even level, and NPV sits beside it. In our example, 1.21 passes the first test, 0.83 fails the second, and the break-even level shows benefits can slip only 17.5%.

• Stress test. Cut benefits by 20% and raise capital cost by 20%. Our recommendation is to take the ratio forward only if it stays at or above 1.0, or to state plainly why the programme proceeds anyway.
• Scale. A ratio hides size. A ₹5 lakh outlay returning ₹30 lakh in present value has a ratio of 6.0 and an NPV of ₹25 lakh. A ₹6 crore outlay returning ₹15 crore has a ratio of 2.5 and an NPV of ₹9 crore. The second creates far more value despite the lower ratio. These two projects are our own illustration.
• Budget limits. When funds are capped, the ratio helps rank options because it shows value per rupee; without a cap, NPV is the better guide. Our project prioritisation framework page sets out the wider ranking choice.
• Below 1.0. A ratio under 1.0 is not an automatic rejection when the programme exists for a reason you cannot price. In our judgement, such a case needs the benefit named, the cost of delivering it stated, and the approver's sign-off recorded.

The ratio is one number inside a programme business case.

The ratio only reflects the benefits and costs you identify. Our Program Management Essentials course teaches the business case and benefits side. Module 4, Program Risk Management, includes a Program Business Case Basics lesson. Module 6, Benefits Planning & Value Realization, covers what a benefit is, identifying and categorising benefits, benefit management, transition and sustainment.

Program Management Essentials is a foundation course, not a PgMP® exam-preparation course. It has 15+ hours of video and monthly live Q&A sessions, and costs US$99 per enrolment as of October 2026.

We have mentored or trained more than 6,000 professionals. Before you enrol, you can take a free discovery or eligibility consultation to check the course suits your role, and we will confirm the amount payable in India. Book it by writing to support@augmentconsultancy.com or calling or messaging us on WhatsApp at +91 9816 360 116.