Confession: I spent 3 hours calculating reward optimization for a ₹500 purchase

by shreya.kulkarni · 4 Nov 2025, 02:32 pm · 1377 views · 20 replies

shreya.kulkarni OP

shreya.kulkarni

4 Nov 2025, 02:32 pm

Had a moment of self-awareness today that I need to share with people who might understand (only this community will).

Last night I wanted to order dinner from Swiggy. Bill was ₹485. And then I went down the rabbit hole:

Opened 4 browser tabs comparing card offers
Calculated whether to add ₹15 more to hit ₹500 threshold for HDFC offer
Checked if Axis Magnus 10X would be better than HDFC ₹125 off
Googled "swiggy hdfc offer vs axis magnus effective reward rate reddit"
Made an Excel sheet (yes, really)
Converted reward points to INR at different redemption rates
Factored in annual fees amortized monthly
Considered whether to save the HDFC monthly offer for later in the month

Final calculation: HDFC offer saves ₹15 more than Magnus rewards.

Time spent: 3 hours.

My hourly salary: ₹800 (if calculated from monthly CTC).

Net loss from this exercise: ₹2,400 - ₹15 = -₹2,385

I'm an accountant by profession. I literally do this for a living. And here I am, applying NPV calculations to a butter chicken order.

My girlfriend walked into the room, saw the Excel sheet on my screen, asked what I was doing, I explained, and she just... stared at me. Then said "It's dinner, not a mutual fund investment" and walked away.

She's not wrong but also she doesn't understand the PRINCIPLE of it. It's not about the ₹15. It's about OPTIMIZING. It's about knowing you squeezed every possible paisa of value.

Anyway I finally used HDFC, got the ₹125 off, felt victorious for 5 minutes, then realized my food was cold because I spent 3 hours calculating instead of ordering.

Tell me I'm not alone. Please.

19 Comments

ananya.reddy · 8 Nov 2025, 06:18 pm

I feel personally attacked by this post and I don't appreciate it

rohan.kapoor · 11 Nov 2025, 08:31 pm

Brother you are among friends here. We ALL do this. The only difference is you admitted it publicly.

rajesh.nambiar · 20 Nov 2025, 07:28 pm

The Excel sheet is where you lost me fam. I just do mental math for 10 minutes while the cart times out. Much more efficient (not really).

harsh.agarwal · 24 Nov 2025, 03:16 am

The worst part is you KNOW it's irrational but you CAN'T STOP. It's like a compulsion. I need that perfect optimization dopamine hit.

harsh.agarwal · 3 Dec 2025, 09:38 pm

This is why we need a CardNitty Anonymous group. 'I calculated EMI interest rates for a chocolate bar purchase just to see if I could game the system'.

rahul.joshi · 17 Dec 2025, 04:17 pm

The concerning part is this post has 100% relatability in this community. Outside this forum we'd be in therapy. Here we're among peers sharing optimization tactics.

amit.verma · 12 Nov 2025, 07:28 pm

My wife caught me with SEVEN browser tabs open comparing 0.5% cashback differences on a ₹200 grocery order. I had to explain marginal utility theory. She threatened divorce (jokingly... I think).

rohan.kapoor · 27 Nov 2025, 12:54 pm

Counter-argument: You spent 3 hours LEARNING optimal strategies that you'll use for years. That's investment in knowledge. Amortize it over future purchases. See? Still makes sense! (We're all insane).

divya.pillai · 6 Dec 2025, 05:37 am

The cold food part hit different. I've done this. Optimize for 90 minutes, order, realize restaurant is now closed. Re-optimize for new restaurants. Husband orders from Domino's in frustration.

deepika.menon · 14 Dec 2025, 11:56 am

I explained my Infinia SmartBuy → voucher → point transfer → airline redemption strategy to my wife once. She said 'or you could just pay normal price and save time'. She doesn't get it. I'm filing for divorce (kidding).

rohan.kapoor · 16 Nov 2025, 02:33 pm

This is literally a support group at this point right? Should we have weekly meetings? 'Hi my name is Rohan and I calculated reward rates for a 3-star petrol pump'

aditya.singh · 21 Nov 2025, 06:09 am

I once drove 15 minutes to a different petrol pump because my usual one stopped giving fuel surcharge waiver. I spent ₹40 in extra fuel to save ₹12 in surcharge. My logic was 'but PRINCIPLES'.

priya.sharma · 23 Nov 2025, 07:48 am

Your girlfriend's response is gold. My husband gives me the same look now. I've learned to do the calculations BEFORE announcing dinner plans.

pooja.desai · 27 Nov 2025, 07:39 pm

I have a Google Sheet with 47 different purchase scenarios pre-calculated by card. When I buy anything I just Ctrl+F the category. Yes I'm fun at parties.

deepika.menon · 27 Nov 2025, 08:43 pm

@Google Sheet guy - Can you share that template? Asking for a friend (the friend is me).

ishita.sen · 1 Dec 2025, 12:58 am

My record is 2.5 hours optimizing an ₹85 Zepto order. The issue was whether to add ₹15 more to hit ₹100 discount threshold. Spoiler: I added bananas I didn't need. Bananas are now rotten. I saved ₹8.

rahul.joshi · 10 Dec 2025, 01:21 pm

Honestly the Excel sheet shows dedication. I just keep it all in my head like a Beautiful Mind situation. My family thinks I'm calculating physics equations when I'm really doing reward rate arbitrage.

nikhil.rao · 10 Dec 2025, 05:13 pm

Real talk though: This hobby made me genuinely better at finance. I understand interest rates, time value of money, opportunity cost. That's worth something. Still ridiculous for ₹500 Swiggy order tho.

ishita.sen · 12 Dec 2025, 03:30 am

'It's about the PRINCIPLE' is the credit card optimizer's mating call. We all say this. Our partners all ignore it.

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