Reusable Diaper vs Disposable Diaper Cost Calculator

Why compare cloth and disposable diaper costs?

Choosing diapers is one of the first recurring budget decisions many families face. Disposable diapers feel simple—buy, use once, toss—but they create an ongoing per-diaper expense that scales directly with how many changes your baby needs. Cloth diapers usually require a larger upfront purchase plus repeated laundry costs, but the same diapers can be reused many times and may retain some resale or donation value at the end.

This calculator focuses on a straightforward financial question:

• Break-even days: how many days it takes until the total cost of cloth (upfront cost − resale value + washing) becomes less than the total cost of disposables.

What each input means (and common interpretation pitfalls)

• Price per cloth diaper ($): the per-diaper purchase price for your cloth system (including inserts if they’re bought per diaper).
• Number of cloth diapers needed: how many you plan to own in your rotation (often driven by how frequently you wash and how fast diapers dry).
• Washing cost per use ($): this calculator treats “use” as one diaper washed (a per-diaper laundry cost). If you think in “cost per load,” convert it to per-diaper by dividing your estimated load cost by the number of diapers (and other items) washed in that load.
• Price per disposable diaper ($): the average per-diaper price after coupons, bulk pricing, subscriptions, etc.
• Diapers used per day: average changes per day (use your best estimate; newborns often use more than older babies).
• Resale or donation value of cloth set ($): what you expect to recover at the end (resale) or the value you want to credit yourself for donating. Enter 0 if you don’t want to include this.

Formulas used

The calculator compares cumulative cost over time.

• Upfront cloth cost: clothUpfront = clothPrice × clothQty
• Net cloth initial cost after resale value: clothInitialNet = clothUpfront − resale
• Daily disposable cost: dailyDisposable = disposablePrice × diapersPerDay
• Daily washing cost (for cloth): dailyWashing = washingCost × diapersPerDay

Break-even occurs when:

clothInitialNet + dailyWashing × D = dailyDisposable × D

Solving for D (break-even days):

D = (clothInitialNet) / (dailyDisposable − dailyWashing)

Here is the same formula in MathML (so it can render cleanly in supporting browsers and assistive tech):

Where:

• C = price per cloth diaper
• Q = number of cloth diapers needed
• R = resale/donation value of the cloth set
• P = price per disposable diaper
• W = washing cost per diaper washed
• N = diapers used per day

Interpreting your results (including edge cases)

• If break-even days is a positive number: cloth becomes cheaper after that many days of use (on average).
• If the denominator (dailyDisposable − dailyWashing) is ≤ 0: your estimated washing cost per diaper is equal to or greater than the disposable cost per diaper. In that case, cloth does not “pay back” financially within this model (because each day of cloth use costs as much as or more than disposables, before even considering the upfront purchase).
• If resale value is high: it reduces the effective upfront cost, moving break-even earlier. If resale value exceeds upfront cost, the “break-even” may be immediate (though that situation is uncommon and depends on your local resale market and diaper condition).

Worked example

Suppose you buy 24 cloth diapers at $20 each:

• Cloth upfront cost = 20 × 24 = $480
• Expected resale value = $100
• Net cloth initial cost = 480 − 100 = $380

Assume:

• Washing cost per diaper washed = $0.10
• Disposable price per diaper = $0.30
• Diapers used per day = 8

Then:

• Daily disposable cost = 0.30 × 8 = $2.40/day
• Daily washing cost = 0.10 × 8 = $0.80/day
• Daily savings using cloth (vs disposables) = 2.40 − 0.80 = $1.60/day

Break-even days:

D = 380 / 1.60 = 237.5, so about 238 days (around 8 months).

Note: if you previously saw examples implying ~150 days with these same numbers, that usually comes from a different washing-cost interpretation (for example, treating $0.10 as a per-day cost or using a smaller net upfront cost). This calculator is consistent: washing cost is per diaper washed.

Scenario comparison table

The table below shows how sensitive break-even time is to disposable price, washing cost, and daily diaper use. (Assumes the same cloth purchase and resale value across scenarios.)

Limitations and assumptions

• Per-diaper washing cost assumption: the model uses a per-diaper washing cost. If your real costs are per load, you must convert to per diaper for best accuracy.
• Same diaper usage rate: it assumes the baby uses the same number of diapers/day in either system. Mixed use (cloth at home, disposable overnight/travel) will change both the daily cost and the break-even time.
• Doesn’t price your time: laundering, stuffing, folding, and managing diapers takes time. This calculator doesn’t monetize that effort.
• Doesn’t include accessories: pails, wet bags, liners, boosters, diaper creams, extra detergent, and washer/dryer wear can matter. You can approximate these by increasing either cloth price per diaper or washing cost per use.
• Doesn’t include multiple children: reusing the same cloth set for another child typically makes cloth more favorable because the upfront cost is spread over more days.
• No time value of money: cloth costs are paid upfront while disposables are paid gradually. If you care about financing/interest, you’d need a discounted cash-flow approach.
• Environmental impact not scored: landfill waste, water use, and energy use are important but are outside the scope of this purely cost-based model.

FAQ

What if washing cost is higher than disposables?

If your washing cost per diaper (W) is greater than or equal to the disposable cost per diaper (P), then dailyDisposable − dailyWashing ≤ 0 and cloth won’t reach a financial break-even in this simplified model.

Is “washing cost per use” per load or per diaper?

In this calculator it’s per diaper washed. If you only know cost per load, estimate: per-diaper cost = load cost ÷ number of diapers in the load (optionally including other laundry items that share the load).

How does resale value affect the result?

Resale value reduces the effective upfront cost of cloth (clothPrice × clothQty − resale). Higher resale value moves break-even earlier; a resale of 0 makes break-even later.

How many cloth diapers do I need?

It depends on how often you wash and dry. More diapers usually means fewer emergency washes and less need to use disposables, but it increases upfront cost. Use a number that matches your planned washing cadence.