ENERGY · FX · HOUSEHOLD

Brent + INR Sensitivity: OMC Margins & Fuel Bills

How crude and currency move pump prices, gross marketing margins (GMM), and your monthly fuel bill—using practical, directional math.
By bataSutra Editorial · October 16, 2025
In this piece:
  • The short — five-line brief
  • Formula: from Brent & USD/INR to pump price
  • OMC margin ladder (illustrative)
  • City bands & household math
  • What can break the math (policy, inventories, cracks)

The short

  • Direction: Lower Brent and a stable INR usually widen OMC GMM and keep retail bands steady.
  • Sensitivity: ~₹0.40–₹0.60/L per US$1/bbl move (diesel closer to the high end); ~₹0.50–₹0.70/L per ₹1 on USD/INR.
  • Inventory lag: Spot changes drip into pumps with a lag; clean trends matter more than one-day moves.
  • Policy: Excise/VAT tweaks or ad-hoc retail band management can override pure-cost signals.
  • Households: City bands allow budgeting; EV math still wins on per-km energy cost, finance costs aside.

Formula — from Brent + USD/INR to pump price (simplified)

Pump price (₹/L) ≈ landed product cost (Brent × crack × FX) + freight + OMC opex + dealer margin + central excise + state VAT.

  • Brent: Base crude marker.
  • Cracks: Product spreads (gasoline/diesel) vs crude; move independently and shift margins.
  • FX: Most inputs priced in USD; INR depreciation lifts landed cost.
  • GMM (₹/L): Pump price net of taxes − landed cost − logistics/opex.

Tip Use trends, not ticks. A 2–3 week drift in Brent/INR is more predictive of retail adjustments than a 24-hr spike.

OMC margin ladder (illustrative)

ScenarioBrent (US$/bbl)USD/INRIndicative petrol GMM (₹/L)Indicative diesel GMM (₹/L)Comment
A6083₹4.5–6.0₹5.0–6.5Benign; room for promo/retail band stability
B7084₹3.0–4.5₹3.5–5.0Comfortable if cracks don’t spike
C8086₹1.0–2.5₹1.5–3.0Tight; selective under-recovery risks appear
D7588₹0.5–2.0₹1.0–2.5FX hurts more than Brent in short bursts
Rule of thumb: Watch crack spreads; a diesel crack spike can compress GMM even if Brent is stable.

City bands & household math (illustrative)

CityPetrol (₹/L)Diesel (₹/L)Note
Delhi102–10590–93Baseline bands
Mumbai106–11093–97Higher VAT/cess
Bengaluru102–10688–92Recent tax resets reflected
Chennai101–10492–95Levy mix different

Monthly car fuel bill (Delhi band)

  • 1,000 km @ 14 km/L (petrol): ₹7,250–₹7,500
  • 1,000 km @ 18 km/L (diesel): ₹5,000–₹5,200
  • EV @ 7 km/kWh, ₹9/kWh: ~₹1,285 (ex-parking/finance)

What can break the math

  • Tax changes (excise/VAT) or temporary retail band management.
  • Inventory timing (older, costlier cargoes vs new spot purchases).
  • Crack spread spikes (especially diesel) independent of Brent.