How should I estimate gas or trip cost?

A simple method is to multiply round‑trip miles by your vehicle’s fuel cost per mile (fuel price per gallon ÷ miles per gallon), then add parking or transit fares. If that feels too detailed, you can enter a rough estimate based on typical trips.

What if my state treats online sales tax differently from local sales tax?

Use the tax rate field to approximate the effective rate for each scenario. If online purchases are not taxed or taxed at a different rate, you can run the calculator separately or adjust the base prices to approximate the difference.

Should I factor in my time when comparing local vs online?

This calculator focuses on direct monetary costs (price, tax, shipping, gas). Your time has value too—consider travel time, waiting in line, and handling returns when making your final decision.

Can I include coupons or rewards points?

Yes—adjust the local or online prices to reflect discounts or rewards before entering them. The calculator will then reflect the net price after those savings.

Does this handle returns or warranty differences?

Not directly. Returns may involve extra shipping or travel, and warranties may differ between local and online purchases. Consider those factors separately for high-value or complex items.

everyday calculator

Local Retail vs Online Purchasing

Compare total cost of buying locally versus online by including sales tax, shipping, and a simple gas cost to reach the store.

Results

Local sales tax: $8
Local total: $133
Online tax (if applicable): $8
Online total: $118
Cheaper option: online
Savings vs higher-cost option: $16

How to use this calculator

Enter the local price (what the item costs at the store before tax) and the online price (the item cost on the website before shipping and tax).
Enter your applicable sales tax rate, and indicate whether it applies to local, online, or both, depending on your jurisdiction and the retailer.
Enter the shipping cost (if any) for the online purchase.
Enter an estimated gas or trip cost for visiting the local store—this can be the cost of fuel, parking, or transit.
Review the calculated local total and online total, along with the indication of which option is cheaper and by how much.
Optionally, tweak shipping, gas, or tax assumptions to test different scenarios such as free‑shipping promotions or tax‑free local events.

Inputs explained

Local price: The pre‑tax price for the item at your local store. Use the shelf price or quoted price before sales tax is added.
Online price: The item’s price at the online retailer before shipping and tax. If there are coupon discounts, subtract those from the price before entering it.
Sales tax rate: Your combined sales tax rate as a percentage (state + local). Use the rate that applies to local, online, or both purchases depending on how your state treats online sales.
Shipping: Shipping and handling charges for the online purchase. Enter 0 if shipping is free or included in the price.
Gas/trip cost: A simple estimate of what it costs you to go to the store in fuel, parking, tolls, or transit. For a quick estimate, multiply miles driven by your vehicle’s fuel cost per mile.

How it works

We treat your local and online prices as base prices before extra costs are added.

For the local option, we add sales tax (based on your tax rate) and any estimated gas or trip cost you enter to get a full “out‑the‑door” local total.

For the online option, we add shipping and, if applicable, sales tax to the online price to get the full online total.

We then compare the two totals, flag which one is cheaper, and calculate the difference in cost between buying local and buying online.

Because tax rules vary, you can model cases where both local and online purchases are taxed at the same rate or where one option has no tax or different effective rates.

Formula

Local total ≈ Local price + (Local taxable base × Local tax rate) + Gas/trip cost\nOnline total ≈ Online price + (Online taxable base × Online tax rate) + Shipping\nSavings = Higher of (Local total, Online total) − Lower of (Local total, Online total)

When to use it

Deciding whether to buy a specific item locally or online when base prices, tax, and shipping differ.
Illustrating how sales tax, shipping, and gas change the “real” price of items that look cheaper at first glance.
Testing cases where an online price is lower before shipping but ends up higher once shipping and tax are included.
Comparing the effective cost of buying from a local small business versus a big online retailer when you want to support local shops but still stay within budget.
Evaluating whether a trip to a distant store for a special sale is worth the extra fuel and time compared to ordering online.

Tips & cautions

If your state collects online sales tax, use the same tax rate for both local and online totals; if not, you can model a 0% tax rate for online purchases.
Gas cost is a simple proxy; for more accuracy, estimate miles driven × fuel cost per mile, and add parking or transit fares as needed.
Include any pickup fees, delivery surcharges, or membership fees (like warehouse club or premium shipping memberships) on the appropriate side if they meaningfully affect your decision.
Remember to consider non-price factors such as product availability, return convenience, supporting local businesses, and delivery speed when making the final choice.
Does not automatically model coupons, promo codes, or rewards points—enter net prices after discounts manually if you want to include them.
Assumes a single tax rate input; if your local and online purchases have different effective tax rates, you’ll need to approximate using separate runs or adjusted rates.
Does not factor in the value of your time spent driving, waiting, or handling returns, which can be significant in real decisions.
Return shipping costs, restocking fees, and warranty differences are not included but may matter for certain items.

Worked examples

Online looks cheaper until you add shipping

Local price = $100, Online price = $95, Tax rate = 8%, Shipping = $15, Gas = $4.
Local total ≈ 100 + (100 × 0.08) + 4 = 100 + 8 + 4 = $112.
Online total ≈ 95 + (95 × 0.08) + 15 ≈ 95 + 7.60 + 15 = $117.60.
Interpretation: despite the lower online price, shipping pushes the online total above the local total by about $5.60.

No online tax, free shipping vs local tax and gas

Local price = $120, Online price = $120, Tax rate = 9% local, 0% online, Shipping = $0, Gas = $6.
Local total ≈ 120 + (120 × 0.09) + 6 = 120 + 10.80 + 6 = $136.80.
Online total ≈ 120 + 0 + 0 = $120.
Interpretation: in this scenario, buying online saves about $16.80 compared to driving to the store and paying local tax.

Modeling a distant store trip for a sale

Local sale price in a distant city = $80, Online price = $90, Tax rates same, Shipping = $0, Gas/trip cost = $12.
Run the calculator with those inputs and compare the totals.
Interpretation: even with a lower sale price, the added gas cost may erase most of the savings, helping you decide whether the trip is worthwhile.

Deep dive

Compare buying local vs online by adding sales tax, shipping, and gas or trip costs to see which option truly costs less.

Enter local and online prices, tax, shipping, and gas to find the lower-cost option for your purchase and understand how hidden costs affect the real price.

Ideal for shoppers who want to balance savings, convenience, and support for local businesses by making fully-informed decisions.

FAQs

How should I estimate gas or trip cost?: A simple method is to multiply round‑trip miles by your vehicle’s fuel cost per mile (fuel price per gallon ÷ miles per gallon), then add parking or transit fares. If that feels too detailed, you can enter a rough estimate based on typical trips.
What if my state treats online sales tax differently from local sales tax?: Use the tax rate field to approximate the effective rate for each scenario. If online purchases are not taxed or taxed at a different rate, you can run the calculator separately or adjust the base prices to approximate the difference.
Should I factor in my time when comparing local vs online?: This calculator focuses on direct monetary costs (price, tax, shipping, gas). Your time has value too—consider travel time, waiting in line, and handling returns when making your final decision.
Can I include coupons or rewards points?: Yes—adjust the local or online prices to reflect discounts or rewards before entering them. The calculator will then reflect the net price after those savings.
Does this handle returns or warranty differences?: Not directly. Returns may involve extra shipping or travel, and warranties may differ between local and online purchases. Consider those factors separately for high-value or complex items.

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This local vs online cost calculator provides a simplified comparison of direct monetary costs using user-entered prices, tax, shipping, and gas/trip estimates. It does not implement detailed tax law, account for time value, returns, or warranty differences, and is intended for personal budgeting and shopping decisions only. For large purchases or business decisions, consider additional factors and professional advice as needed.