Decision Calculator
Big Purchase Timing Calculator
See how buying a car, renovation, wedding, boat, or other large purchase now vs. later affects your future wealth, timing, and opportunity cost.
Purchase type
Key insight
Waiting 3 years leaves you $19K ahead at year 10 thanks to extra compounding time.
Buy now vs wait
+$19K
Cost of buying (best)
$65K
Key insight
Waiting 3 years leaves you $19K ahead at year 10 thanks to extra compounding time.
Buy now vs wait
+$19K
Cost of buying (best)
$65K
Total net worth over time
The chart compares three scenarios over 10 years: buying now, waiting 3 years, and skipping the purchase entirely. The dashed line marks the delayed purchase date. Toggle between total net worth (including retained item value) and invested portfolio only.
Scenario comparison at year 10
Buy now net worth
$389K
Buy in 3 yrs net worth
$408K
Skip purchase net worth
$473K
Key metrics
Sticker cost today
$50,000
Future sticker cost (yr 3)
$54,636
Retained value (buy now)
$14K
Opportunity cost (buy now)
$84K
Opportunity cost (buy later)
$65K
Timing difference
+$19K
What’s driving this
A $50,000 car purchased today would cost $54,636 if bought in 3 years due to 3% annual cost inflation. Waiting puts you $19K ahead at year 10 because the extra compounding time more than offsets the inflated future price. The item retains $14K in value at year 10, reducing the effective cost.
Why timing matters for big purchases
A major purchase doesn’t just cost the sticker price—it also costs whatever that money could have earned if invested. This “opportunity cost” can dwarf the purchase itself over long time horizons thanks to compound growth.
But waiting isn’t always the clear winner. The future price of the same item or service typically rises with inflation. A car that costs $50,000 today might cost $58,000 in five years. And some purchases retain real asset value—a renovation might add equity, while a wedding leaves no financial residual.
Inflation vs. depreciation: two separate forces
This calculator models two distinct dynamics that are often conflated:
- Future purchase inflation — What an equivalent item would cost if you buy it later. This raises the future sticker price.
- Post-purchase appreciation or depreciation — What the item is worth after you own it. A car depreciates, while a home renovation may partially retain value.
The real cost of a purchase is not just what you pay—it’s also what that money could have become and how much value the purchase retains.
This calculator is for educational purposes only and does not constitute financial advice. Projections assume constant rates of return, inflation, and depreciation. They do not account for taxes, transaction costs, financing, or individual circumstances. Actual outcomes will vary. Consult a financial advisor for personalized guidance.