Quick answer: A second stop is worth it when item savings are greater than extra miles × your cost per mile plus extra minutes × the value of your time. Add only stores that clearly beat your main store on a short list of items you buy often.
Short answer: a second store is worth it when item savings > trip cost + time cost, written as:
net gain = item savings − (extra miles × cost per mile) − (extra minutes ÷ 60 × value of your time)
If the net gain is positive, go. If it is not, stay with your main store. The multi-store grocery trip calculator runs this for you.
Step 1: Find your cost per mile
You have two useful numbers:
- Fuel only: gas price per gallon ÷ miles per gallon. At $3.50 per gallon and 25 mpg, that is $0.14 per mile. Find your vehicle’s mpg at fueleconomy.gov.
- All-in cost (fuel, tires, maintenance, depreciation, insurance): the IRS standard mileage rate is a common benchmark. The IRS sets the rate from an annual study of the fixed and variable costs of operating a car. For 2026, the business rate is 72.5 cents per mile from January 1 and 76 cents per mile from July 1.
For a short, extra errand, the true cost per mile is somewhere between the two. Use the fuel-only number if the trip is nearly free (on your way), and the higher number for a real detour. Rates change, so check the IRS page for the current figure.
Step 2: Add up extra distance and time
Only count the extra miles and minutes beyond your normal trip. A stop on your way home may add 1 mile and 5 minutes. A store in the opposite direction might add 10 miles and 35 minutes.
Trip cost by distance and cost per mile
| Extra miles (round trip) | $0.15 per mile | $0.30 per mile | $0.76 per mile |
|---|---|---|---|
| 2 | $0.30 | $0.60 | $1.52 |
| 5 | $0.75 | $1.50 | $3.80 |
| 10 | $1.50 | $3.00 | $7.60 |
| 20 | $3.00 | $6.00 | $15.20 |
Time cost by minutes and hourly value
| Extra minutes | $0 per hour | $10 per hour | $20 per hour |
|---|---|---|---|
| 15 | $0 | $2.50 | $5.00 |
| 30 | $0 | $5.00 | $10.00 |
| 45 | $0 | $7.50 | $15.00 |
Step 3: Add up your item savings
Compare the unit price of the same items at each store, not just the shelf price. See which is cheaper: comparing grocery sizes and units and unit price explained. The grocery price comparison calculator helps with the math.
Count only what you would actually buy there, and only the savings, not the total spent.
The break-even basket
If the other store is cheaper by a certain percentage on everything you buy there, you can calculate the minimum basket:
minimum basket = trip cost ÷ price gap
| Trip cost (miles + time) | 5% cheaper | 10% cheaper | 15% cheaper | 20% cheaper |
|---|---|---|---|---|
| $3 | $60 | $30 | $20 | $15 |
| $5 | $100 | $50 | $33 | $25 |
| $8 | $160 | $80 | $53 | $40 |
This is why a second store works best for big, planned stock-ups and not for a single item.
Worked examples
1. Staples stop on the way home. Extra 1 mile (about $0.30) and 5 minutes ($0.83 at $10 per hour). You save $9.00 on $60 of pantry staples. Net gain: $7.87. Worth it.
2. Warehouse club run. Extra 10 miles round trip ($3.00 at $0.30 per mile) and 40 minutes ($6.67 at $10 per hour). You spend $120 and save 18%, or $21.60. Net gain: $11.93. Worth it, provided you already have a membership. See is a Costco membership worth it.
3. Cheaper store for milk and eggs only. You save $2.40. The extra 6 miles cost $1.80 and 15 minutes costs $2.50. Net gain: −$1.90. Not worth it.
4. Three-store loss leader hunt. You save $14 in total across the sales. The extra 12 miles cost $3.60 and 50 minutes costs $8.33. Net gain: $2.07. Technically positive, but small for the effort and the impulse buys risk.
5. Same example with the IRS all-in rate. At $0.76 per mile, Example 2 costs $7.60 in miles, so net gain is $21.60 − $7.60 − $6.67 = $7.33. Still worth it, but with a narrower margin.
What to buy at a second store
Good candidates:
- Pantry staples (rice, pasta, beans, canned goods, oils)
- Frozen foods and meat you can freeze
- Paper goods, cleaning supplies, and personal care items
- Anything where you have seen a price gap of 20% or more in your price book
Better at your main store:
- Fresh produce and dairy, unless the other store is much cheaper
- Small, one-off items
- Anything you would only buy because it is on sale
See is buying in bulk actually cheaper before you stock up, and cheapest grocery stores ranked for where to start comparing.
The hidden cost: impulse buys
Every extra store is a chance to buy things that were not on your list. Unplanned spending is the quickest way to turn a $10 saving into a loss.
- Go with a written list and a spending cap.
- Eat first, and shop alone if you can.
- Keep a short “only buy” list for the second store.
A simple system that works
- Pick a main store where you do most of your shopping and know the prices.
- Track 10 to 20 items you buy often in a price book for 3 to 4 weeks, at two or three nearby stores.
- Find the items where another store is clearly cheaper (about 20% or more, or about $1 or more per purchase).
- Buy them in bulk, in one trip every 2 to 4 weeks, combined with another errand.
- Re-check twice a year, since prices change. See why grocery prices change month to month.
Also check how to save money at the grocery store for savings that need no extra driving, and the grocery savings calculator to see what a few percentage points add up to over a year.
Trip chaining
Combine the second store with something you are already doing, such as driving past it on the way to work, picking up a child, or going to the pharmacy. When the extra miles and minutes drop near zero, almost any savings is worth it.
Quick cheat sheet
- Net gain = item savings − miles × cost per mile − hours × value of time
- Cost per mile: fuel only ≈ gas price ÷ mpg. All-in ≈ IRS rate (76 cents from July 1, 2026)
- Minimum basket = trip cost ÷ price gap
- Count only extra miles and minutes
- Use unit prices from a price book
- Beware impulse buys
Limits of this guide
Fuel prices, mileage rates, and store prices change, and the dollar figures in the examples are illustrative. The value of your time is personal. The IRS rate is a tax benchmark for business driving, not a measure of your personal cost.
Sources
- Internal Revenue Service, Standard mileage rates
- Internal Revenue Service, IRS sets 2026 business standard mileage rate at 72.5 cents per mile
- U.S. Department of Energy, FuelEconomy.gov (vehicle fuel economy)
- National Institute of Standards and Technology, Handbook 130, Uniform Unit Pricing Regulation
Last reviewed October 7, 2026.
Evergreen method
Compare usable cost, not package price
The durable comparison is price per common unit adjusted for the share you will actually use.
Formula
usable unit cost = price ÷ (quantity × usable share)Reproducible steps
- 1.Convert every option to the same unit.
- 2.Estimate the share your household will use before spoilage.
- 3.Choose the lower usable unit cost only if storage and cash flow also work.
Put it to work
Run the numbers for your household
FAQ
Common questions
Is it worth going to two grocery stores?
It is worth it if your net savings are positive. Net savings = item savings − (extra miles × cost per mile) − (extra minutes ÷ 60 × the value of your time). A short stop on your way home for staples often wins. A 20-minute detour to save $2 does not.
How do I figure out my cost per mile?
For fuel only, divide the price of a gallon of gas by your car's miles per gallon, such as $3.50 ÷ 25 mpg = $0.14 per mile. For the all-in cost, including wear, tires, depreciation, and insurance, the IRS business mileage rate is a common benchmark. The IRS set it at 76 cents per mile starting July 1, 2026.
Should I count the value of my time?
Yes, but it is your choice how much. Many people use $0 if the stop is enjoyable or on their way, and $10 to $20 per hour if it is a real detour. The point is to compare the saving with what the stop costs you in effort.
How much do I need to save to make a second store worth it?
Divide the trip cost by the price gap. If the extra trip costs you $5 and the other store is 10% cheaper, you need to spend at least $50 there to break even. At a 20% gap, $25 is enough.
Is it worth driving farther for cheaper gas or groceries?
Only if the savings are larger than the extra driving. Driving 10 extra miles round trip at 76 cents per mile costs $7.60, which could wipe out a $5 savings on gas or groceries.
What should I buy at a second store?
Items you buy often, that keep well, and where the price gap is large: pantry staples, frozen foods, meat you can freeze, paper goods, and household items. Buy produce and dairy at your main store unless the price gap is big.
Does shopping at multiple stores make people spend more?
It can. Each extra store adds chances for impulse buys. If you spend $8 on unplanned items, you can erase a $6 savings. Go with a list, and a set limit on what you will buy at the second store.
How often should I make a second-store trip?
For staples that keep well, once a month or once every two weeks is common. Stock up on sale or low-price items so you only need the extra trip occasionally. A price book shows which items are worth the trip.
Is grocery pickup or delivery cheaper than an extra trip?
It depends on fees, markups, and tips. Add the service fees and any price markup to the cost of the order and compare that with the in-store total plus travel and time cost. Free pickup from a store can beat a detour if the item prices match.
How can I compare prices between stores accurately?
Compare the unit price (price per ounce, pound, or count) of the same items, not the shelf price. Use the same brand or the store brand at each store, and track 10 to 20 items you buy often in a price book for a month.
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