The Monthly Payment Calculator Your Wallet Actually Wanted: iPhone, iPad, MacBook, Gaming PC

The number the marketing never shows you

Every financing option on every tech retailer's website leads with a monthly payment. Most of them lie: not about the number, but about what the number actually means.

"$33/month" on an iPhone is technically true. It's also the number that turns a $1,199 phone into a $1,739 obligation once you add the carrier plan uplift and trade-in clawback clauses.

"$42/month" on a MacBook is technically true. It's also sometimes the number you pay for 24 months, and sometimes the number you pay for 18 months plus a $400 balloon payment at the end.

"$40/week" on a gaming PC is technically true. It's also a $2,080-a-year commitment on a machine that costs $2,000 retail.

The only way to protect yourself from marketing math is to do your own math. This post is a straightforward guide to calculating the real monthly payment on any financing plan: the formulas, the worked examples, and a calculator you can copy-paste into a spreadsheet for your own use.

We cover the four premium tech categories people finance most often: iPhone, iPad, MacBook, and gaming PC. The formulas work for anything else you can buy, too.

For the underlying breakdown of why these contract types exist, read our pillar post on rent-to-own vs. lease-to-own vs. BNPL.

One label that applies to everything below: every APR and every lease figure in this post is illustrative. Your quoted rate and terms depend on your profile and your provider. The formulas are the point; bring your own numbers.

The four numbers that matter (and nothing else)

Before you use any calculator, you need these four numbers:

1. Retail price: the sticker price of the exact product you want, at the exact retailer you're buying from.
2. APR: the annual percentage rate the lender is charging on the financing. 0% for promotional plans and pay-in-4, somewhere between 10% and 30% for standard longer-term BNPL, and "N/A" for lease-to-own (where the cost is built into the lease rate, not called interest).
3. Term length: the number of months or weeks over which you'll be paying.
4. Any hidden premium: plan uplift, required add-ons, trade-in conditions, processing fees, or lease margins that aren't captured in the advertised APR.

Write all four down before you run any calculation. If you can't find one of them on the retailer's page, ask the retailer in writing. If they won't answer, walk away.

Formula 1: Simple installment plans (pay-in-4 and 0% APR terms)

This is the easy one. When APR is 0%, the math is:

Monthly payment = Retail price ÷ Number of payments

Example: $1,199 iPhone 17 Pro Max, Apple Card Monthly Installments, 24 months, 0% APR.

• $1,199 ÷ 24 = $49.96/month
• Total paid: $1,199

Example: $999 MacBook Air M4, a 3-month installment plan at 0% APR (Affirm offers these at Apple checkout).

• $999 ÷ 3 = $333.00/month
• Total paid: $999

Example: $349 base iPad on Afterpay pay-in-4 (the pay-in-4 option at Tech Buddy: four equal payments, one every two weeks, the first charged at checkout).

• $349 ÷ 4 = $87.25 per payment
• Total paid: $349

Formula 2: Installment loans with interest (longer BNPL terms, store cards)

When there's an APR above 0%, use the standard loan amortization formula:

Monthly payment = P × (r × (1+r)^n) ÷ ((1+r)^n − 1)

Where:

• P = retail price
• r = monthly interest rate (APR ÷ 12, in decimal form)
• n = total number of months

You don't need to do this by hand. Any spreadsheet with the PMT function can handle it:

=PMT(APR/12, months, -price)

Reminder: every APR below is illustrative.

Example: $1,199 iPhone 17 Pro Max, a 24-month plan at 15% APR.

• =PMT(0.15/12, 24, -1199) = $58.17/month
• Total paid: $58.17 × 24 = ~$1,396
• Interest paid: ~$197

Example: $999 MacBook Air M4, a retailer store card at 18% APR, 24 months.

• =PMT(0.18/12, 24, -999) = $49.89/month
• Total paid: $49.89 × 24 = ~$1,197
• Interest paid: ~$198

Example: $2,000 gaming PC, a 36-month plan at 12% APR.

• =PMT(0.12/12, 36, -2000) = $66.43/month
• Total paid: $66.43 × 36 = ~$2,391
• Interest paid: ~$391

Formula 3: Lease-to-own (the hidden-premium calculation)

Lease-to-own contracts don't advertise an APR because they're leases, not loans. The cost of leasing is built into the payment schedule instead. To be fair to the format: the agreement itself states the full schedule and totals before you sign. The advertising usually doesn't, which is why you should run this math before you get to the agreement:

Full-term total = Monthly lease payment × Number of months

Premium over retail = Full-term total − Retail price

Effective markup = Premium ÷ Retail price × 100

Example: $999 MacBook Air M4, 12-month lease at $130/month (illustrative).

• Full-term total: $130 × 12 = $1,560
• Premium over retail: $1,560 − $999 = $561
• Effective markup: $561 ÷ $999 × 100 = 56.2%

That 56.2% markup is what the phrase "no interest" doesn't capture on a full-term lease. It's not interest, legally speaking, but it spends exactly like interest when it leaves your bank account.

The early payoff math (this is why it matters so much):

Early payoff cost ≈ Retail price + Processing fee

For most major lease-to-own providers, the early purchase option in the opening stretch of the agreement (often around 90 days) prices the device near retail plus a fee, typically 5-15%. On a $999 MacBook, that's $50-$150, bringing the early payoff total to $1,049-$1,149: a fraction of the full-term cost. The exact window and price are stated in your agreement; read that section first.

The early payoff effectively converts a lease-to-own contract into a short installment plan with a small premium. Use this formula every time you compare a lease-to-own offer against a BNPL alternative.

Formula 4: Carrier financing (the plan uplift trick)

Carrier installment plans are nominally 0% APR, but the real cost includes a mandatory plan uplift that the phone price doesn't acknowledge. The formula:

Real total = Retail phone price + (Plan uplift per month × Plan term in months)

Example: $1,199 iPhone 17 Pro Max, a 36-month carrier installment plan at 0% APR, with a required post-paid plan tier that costs $15/month more than you'd otherwise pay.

• Phone cost: $1,199
• Plan uplift: $15 × 36 = $540
• Real total: $1,199 + $540 = $1,739

That $540 premium is the single most under-disclosed number in the consumer electronics financing industry. Every carrier installment plan has some version of it. Always add the plan uplift to the phone cost before comparing.

If the carrier offers a trade-in credit:

Real total = (Retail phone price − Trade-in credit) + (Plan uplift × Months) + (Trade-in clawback risk × Months remaining if you switch early)

The clawback risk is the hardest part to model because it depends on whether you'll leave the carrier mid-contract. If there's any meaningful chance you will, assume you'll owe back the remaining unused trade-in credits.

We ran this exact math across six iPhone paths, trade-in clawbacks included, in the iPhone financing showdown.

Formula 5: Rent-to-own (the weekly-payment trap)

Rent-to-own contracts often quote weekly payments to make the number look small. To calculate the real cost:

Full-term total = Weekly rental × Number of weeks to ownership

Example: $999 MacBook Air, rent-to-own at $30/week for 78 weeks (an 18-month ownership path, illustrative).

• Full-term total: $30 × 78 = $2,340
• Premium over retail: $2,340 − $999 = $1,341
• Effective markup: 134.2%

A 134% markup on a MacBook. This is why full-term rent-to-own contracts are rarely the right move on premium electronics.

Always convert weekly payments to monthly and annual totals. Weekly framing makes $30 feel softer than $130/month. They're the same money.

The ready-to-use calculator (copy this into your spreadsheet)

Open Google Sheets or Excel. Recreate this structure, with the labels in column A and the values and formulas in column B:

Cell	Label (column A)	Value or formula (column B)
Row 1	Retail price	1199
Row 2	APR (%)	15
Row 3	Term (months)	24
Row 4	Monthly payment	=PMT(B2/100/12, B3, -B1)
Row 5	Total paid	=B4*B3
Row 6	Total interest	=B5-B1
Row 7	Effective markup (%)	=(B5-B1)/B1*100

Now you can plug in any product, any APR, and any term, and see:

• Your real monthly payment
• The total amount you'll pay
• How much of it is interest
• The effective percentage markup over retail

For lease-to-own, skip the PMT function and use:

• Monthly payment: whatever the provider quoted
• Total paid: monthly × term
• Markup: (total − retail) ÷ retail × 100

For carrier plans, add a row for "monthly plan uplift" and multiply it by the term, then add that to the total cost.

Side-by-side worked examples

Here's the output of running the major financing paths through the calculator for each of the four big premium tech categories. All numbers are representative and illustrative; your actual quotes will vary.

$1,199 iPhone 17 Pro Max

Path	Monthly	Total	Markup
0% APR installment, 24 mo	$50	$1,199	0%
24-mo loan at 15% APR	$58	~$1,392	+16%
Carrier 36-mo (with $15/mo plan uplift)	$33	~$1,739	+45%
Lease-to-own, early payoff (~90 days)	Set in agreement	~$1,260-$1,330	+5-11%
Lease-to-own, full 12-mo term	~$170	~$2,000-$2,400	+67-100%
Rent-to-own, 24-mo full term	~$100	~$2,400	+100%

$999 MacBook Air M4

Path	Monthly	Total	Markup
0% APR installment, 24 mo	$42	$999	0%
Pay-in-4 (Afterpay, Klarna)	$250 per 2 weeks	$999	0%
24-mo loan at 15% APR	$48	~$1,155	+16%
Lease-to-own, early payoff (~90 days)	Set in agreement	~$1,050-$1,150	+5-15%
Lease-to-own, full 12-mo term	~$130	~$1,560	+56%
Rent-to-own, 18-mo full term	~$125	~$2,250	+125%

$549 iPad Air M3

Path	Monthly	Total	Markup
0% APR installment, 24 mo	$23	$549	0%
Pay-in-4 (Afterpay, Klarna)	$137 per 2 weeks	$549	0%
12-mo loan at 12% APR	$49	~$585	+7%
Lease-to-own, early payoff (~90 days)	Set in agreement	~$580-$630	+6-15%
Lease-to-own, full 12-mo term	~$70	~$840	+53%
Rent-to-own, 24-mo full term	~$45	~$1,080	+97%

$2,000 gaming PC

Path	Monthly	Total	Markup
Retailer 0% APR promotional plan, 12 mo	$167	$2,000	0%
36-mo loan at 12% APR	$66	~$2,392	+20%
Lease-to-own, early payoff (~90 days)	Set in agreement	~$2,150-$2,300	+8-15%
Lease-to-own, full 12-mo term	~$283	~$3,400	+70%
Rent-to-own, 24-mo full term	~$160	~$3,840	+92%

The two numbers to always ask for before you sign

Every financing conversation comes down to two questions. Ask them in writing. Always.

1. "What is the total amount I will pay if I make every payment on time for the full term?"

This gets you past the monthly payment framing and forces the provider to disclose the real cost. If they can only give you "it depends," ask for a worked example at a specific price point.

2. "What are my options to pay off early, and what does that total cost look like?"

This uncovers whether there's an early payoff path and how it affects the total. On lease-to-own contracts, this question is the difference between a trap and a useful tool.

If you can't get straight answers to both of these before signing, you're not looking at a financing plan. You're looking at a marketing campaign.

Where to go from here

The honest shortcut: run any financing offer through Formulas 1 through 5 above before you click "confirm." Plug the numbers into the spreadsheet. Look at the total and the markup. Compare it to what the marketing told you. If the two numbers don't match, you now know why.

When you're ready to shop, our laptops and iPads collections (with iPhones, MacBooks, and gaming PCs alongside them) show monthly estimates built on real plan math, not marketing math. The plans behind those numbers at Tech Buddy are Afterpay pay-in-4 (four equal interest-free payments, one every two weeks, the first charged at checkout, soft eligibility check), lease-to-own through Acima or Progressive Leasing (rental-purchase agreements with the full terms stated before you commit, where early payoff reduces the total), and Shop Pay. Run them through Formula 1 and Formula 3 yourself. The numbers will hold up, and free shipping over $29 doesn't change the math, but it's nice.