Metformin Cost in 2026: What You Pay At Walmart, CVS, Costco, and With Insurance

Key Takeaways

• Generic metformin is one of the cheapest prescription drugs in the United States, with cash prices as low as $4 to $10 per month.
• A 30-day supply of generic immediate-release metformin (500 mg twice daily) costs $4 to $25 cash at major U.S. retail pharmacies.
• Brand-name versions like Glucophage and Glumetza cost significantly more, often $200 to $1,000 per month without insurance.
• Most insurance plans cover generic metformin at the lowest copay tier, often $0 to $10.
• Metformin XR (extended release) is a few dollars more per fill than immediate release but follows the same generic pricing pattern.

Direct answer (40-60 words)

Generic metformin costs about $4 to $25 per month for a 30-day supply at major U.S. pharmacies in 2026. Walmart, Costco, and Sam's Club consistently offer the lowest cash prices, often $4 to $10. Brand-name versions such as Glucophage and Glumetza cost $200 to $1,000 monthly. Most insurance plans cover generic metformin with a $0 to $10 copay.

Table of contents

1. The 30-second answer
2. Cash price by pharmacy chain
3. Brand vs generic pricing
4. Immediate release vs extended release pricing
5. Real copay scenarios with insurance
6. Discount cards: GoodRx, SingleCare, Cost Plus
7. Patient assistance programs for low-income patients
8. Why metformin is so cheap
9. Cost compared to GLP-1 medications
10. How to verify your specific cost in 5 minutes
11. FAQ
12. Footer disclaimers

Cash price by pharmacy chain

The Q1 2026 cash price for a 30-day supply of generic metformin 500 mg, twice daily, at major U.S. pharmacies:

Walmart's $4 generic program covers metformin at 500 mg, 850 mg, and 1000 mg strengths. Costco does not require a membership for pharmacy purchases under federal law, so the $4 to $7 cash price is available to non-members.

CVS and Walgreens are the two highest-cost retail pharmacy chains for metformin cash prices. Both accept discount cards like GoodRx and SingleCare, which can bring their prices down to the $5 to $15 range.

Brand vs generic pricing

Metformin is available as a generic and under several brand names. The generic and brand are bioequivalent under FDA standards and produce the same clinical effect.

Generic metformin (immediate release): $4 to $25 per 30-day supply Generic metformin (extended release): $7 to $35 per 30-day supply Glucophage (brand IR): $200 to $400 per 30-day supply Glucophage XR (brand ER): $300 to $500 per 30-day supply Glumetza (brand ER): $500 to $1,000 per 30-day supply Fortamet (brand ER): $400 to $700 per 30-day supply Riomet (liquid metformin): $40 to $90 per 30-day supply

Most insurance plans require generic substitution unless the prescriber specifies "dispense as written" for the brand. Patients prescribed brand metformin without a clinical reason often pay the full out-of-pocket cost because the plan denies coverage at the brand price.

The clinical evidence does not support a meaningful difference in efficacy between brand and generic metformin. The FDA bioequivalence standard requires a 90% confidence interval that the brand and generic deliver between 80% and 125% of the same plasma concentration.

For more on cost-savings strategies for diabetes medications, see our Ozempic cost guide.

Immediate release vs extended release pricing

Generic metformin comes in two formulations: immediate release (IR) and extended release (ER, also called XR). The clinical effect is similar; the main difference is dosing frequency and tolerability.

Immediate release: taken twice or three times daily with meals. The cheapest formulation. $4 to $25 per 30-day supply.

Extended release: taken once daily with the evening meal. Slightly higher cost. $7 to $35 per 30-day supply.

The extended release version is typically chosen for patients who experience GI side effects on the immediate release version. The slower absorption profile reduces nausea and diarrhea for many patients, particularly during the first few weeks of therapy.

A 2018 Cochrane systematic review (Hirst et al., Cochrane Database) found similar HbA1c reduction between IR and ER metformin, with somewhat lower GI side effect rates on the ER formulation. The cost difference is small enough that the formulation choice is usually driven by tolerability rather than price.

Real copay scenarios with insurance

To make the metformin pricing range concrete, here are five anonymized real-world copay scenarios.

Scenario 1: Employer PPO with strong pharmacy benefits. Patient has BlueCross BlueShield through a Fortune 500 employer. Generic metformin is on Tier 1 (preferred generic). Copay is $0 per 30-day fill. Annual cost: $0.

Scenario 2: Employer HMO. Patient has Kaiser Permanente through an employer. Generic metformin is included in the standard formulary at $5 per 30-day fill. Annual cost: $60.

Scenario 3: Marketplace bronze plan. Patient has a marketplace bronze plan through Healthcare.gov with a $7,500 deductible. Generic metformin is Tier 1, but full deductible applies until met. Cash price is paid until deductible is reached: $4 per fill at Walmart. Annual cost: $48.

Scenario 4: Medicare Part D. Patient is 67, retired, on a Medicare Part D plan. Generic metformin is on the lowest tier with a $0 to $5 copay. Annual cost: $0 to $60.

Scenario 5: Medicaid. Patient is enrolled in state Medicaid. Generic metformin is fully covered with a $0 to $4 copay depending on state. Annual cost: $0 to $48.

Scenario 6: Uninsured. Patient pays cash at Walmart's $4 program. Annual cost: $48 for a 30-day-at-a-time fill cycle, or $40 if filled in 90-day increments.

The takeaway: metformin is one of the few prescription drugs where the uninsured cash price at a discount pharmacy is often comparable to or cheaper than insurance copays at full-service pharmacies.

Discount cards: GoodRx, SingleCare, Cost Plus

For patients without insurance or with high-deductible plans where metformin falls under the deductible, three discount programs are widely used.

GoodRx. Free coupons available through the GoodRx app or website. Typical metformin discount price: $4 to $12 per 30-day supply. Accepted at most major pharmacies. Cannot be combined with insurance.

SingleCare. Similar to GoodRx, free to use. Typical metformin discount price: $5 to $14 per 30-day supply. Accepted at most major pharmacies.

Cost Plus Drugs (Mark Cuban Cost Plus). Online-only pharmacy with transparent pricing. Typical metformin price: $3.60 to $9 per 30-day supply, plus a $5 pharmacy fee and $5 shipping. Best for 90-day supplies. Total cost for 90-day supply: $14 to $20 shipped.

For metformin specifically, the Walmart $4 program is often the simplest and cheapest option. The discount cards make a bigger difference at higher-cost pharmacies like CVS and Walgreens.

Patient assistance programs for low-income patients

For patients who cannot afford even the $4 cash price, several patient assistance options exist.

RxOutreach. A nonprofit pharmacy that ships generic medications to qualifying low-income patients. Income threshold is typically 400% of the federal poverty level. Metformin shipping cost is approximately $20 for a 90-day supply.

NeedyMeds. Database of patient assistance programs across manufacturers and nonprofits. Provides referrals rather than direct dispensing.

Manufacturer PAPs. Branded metformin (Glucophage, Glumetza) has limited patient assistance programs through their respective manufacturers. Generic metformin does not have a manufacturer PAP because the price is already low.

340B-eligible community health centers. Federally qualified health centers (FQHCs) and Ryan White clinics often dispense metformin at sliding-scale prices for uninsured patients.

The threshold for needing patient assistance for metformin is unusually low. At $4 per 30-day supply, the drug is one of the most accessible prescription medications in the United States.

Why metformin is so cheap

Metformin's low price reflects three factors:

Off-patent for decades. Metformin's U.S. patent expired in 2002. Multiple generic manufacturers have produced metformin since then, driving competition and pricing down.

Inexpensive to manufacture. Metformin hydrochloride is a small molecule synthesized via well-established processes. Raw material costs and manufacturing costs are both low.

High prescription volume. Metformin is prescribed to more than 80 million Americans, making it one of the highest-volume prescription drugs in the country. High volume amortizes manufacturing fixed costs and supports razor-thin per-tablet margins.

These factors combine to produce the unusual situation where a clinically effective first-line therapy for type 2 diabetes (and an off-label option for prediabetes, PCOS, and weight management) costs less than a single fast-food meal per month.

Cost compared to GLP-1 medications

Patients on metformin sometimes face a question about adding or switching to a GLP-1 receptor agonist. The cost difference is dramatic.

Metformin is often used as first-line therapy and continued alongside or before GLP-1 agonists rather than replaced. The 2024 ADA Standards of Care recommend metformin as initial therapy for most patients with type 2 diabetes, with GLP-1 receptor agonists added when additional glycemic control or weight management is needed.

How to verify your specific cost in 5 minutes

The cleanest way to confirm your out-of-pocket cost for a metformin fill:

1. Look up your insurance plan's online formulary. Search "metformin" and note the tier and copay.
2. If your plan has a deductible, check your year-to-date deductible status in the member portal.
3. Pull up the Walmart or Costco pharmacy pricing on their app for your zip code.
4. If you are uninsured or on a high-deductible plan, search GoodRx and SingleCare for the lowest discount card price.
5. Compare the three numbers (insurance copay, Walmart cash, discount card) and pick the lowest.

For most patients, Walmart's $4 program will be the lowest or tied for lowest. The exception is patients with a $0 generic copay through Tier 1 insurance, where the insurance route is free.

FAQ

How much does metformin cost without insurance? Generic metformin costs $4 to $25 per 30-day supply at major U.S. pharmacies without insurance. Walmart, Costco, and Sam's Club offer the lowest cash prices, typically $4 to $10. CVS and Walgreens are higher, around $20 to $30, but accept discount cards that bring the price down.

How much does metformin cost with insurance? Most insurance plans cover generic metformin at the lowest tier with a $0 to $10 copay. High-deductible plans require the full cash price until the deductible is met, at which point the copay applies.

Is brand-name metformin worth the extra cost? For most patients, no. Generic metformin is bioequivalent to brand-name versions like Glucophage and Glumetza under FDA standards. The clinical evidence does not support a meaningful efficacy difference. Brand metformin can cost 50 to 100 times more than generic.

Why is metformin so cheap? Metformin's patent expired in 2002, and multiple generic manufacturers compete to produce it. Manufacturing is inexpensive, and prescription volume is high (80+ million Americans on metformin). Together, these factors push the cash price below $5 per month.

How much does metformin XR cost? Generic extended-release metformin costs $7 to $35 per 30-day supply, slightly more than immediate-release generic. Brand ER versions like Glumetza or Fortamet can cost $400 to $1,000 per fill.

Does Walmart have a $4 program for metformin? Yes. Metformin 500 mg, 850 mg, and 1000 mg are all included in Walmart's $4 generic program for a 30-day supply, or $10 for a 90-day supply. The program does not require insurance or a membership.

Can I use GoodRx for metformin? Yes. GoodRx coupons typically reduce metformin cash prices to $4 to $12 per 30-day supply at participating pharmacies. GoodRx cannot be combined with insurance, so use it only when paying out of pocket.

How does metformin cost compare to Ozempic or Wegovy? Metformin is dramatically cheaper. Generic metformin is $4 to $25 per month; Ozempic is $940 to $1,150 per month cash, and Wegovy is $1,300 to $1,500. Metformin is typically used as first-line therapy with GLP-1 medications added when needed.

Does Medicare cover metformin? Yes. All Medicare Part D plans cover generic metformin at the lowest tier, typically with a $0 to $5 copay. Brand metformin coverage varies by plan.

Does Medicaid cover metformin? Yes, in all states. Generic metformin copays under Medicaid are typically $0 to $4 depending on state rules.

Is liquid metformin (Riomet) covered by insurance? Liquid metformin is more expensive ($40 to $90 per 30-day supply cash) and is not always preferred on insurance formularies. Coverage depends on the plan, and prior authorization may be required.

Can I buy metformin without a prescription in the United States? No. Metformin requires a prescription in the United States, even though it is available over the counter in some other countries. A telehealth visit can typically produce a prescription within 24 to 48 hours for patients with appropriate clinical indications.

Sources

1. American Diabetes Association. Standards of Care in Diabetes 2024. Diabetes Care. 2024;47 Suppl 1.
2. Hirst JA, et al. Quantifying the effect of metformin treatment and dose on glycemic control. Cochrane Database Syst Rev. 2018.
3. U.S. Food and Drug Administration. Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book), metformin entries, 2026.
4. Walmart Pharmacy. $4 Prescription Program drug list, accessed Q1 2026.
5. Costco Wholesale. Pharmacy member pricing, accessed Q1 2026.
6. Centers for Medicare and Medicaid Services. Medicare Part D formulary data, 2026 plan year.
7. NeedyMeds. Patient assistance program directory, accessed Q1 2026.
8. Mark Cuban Cost Plus Drug Company. Public pricing list, accessed Q1 2026.
9. Inzucchi SE, et al. Metformin in patients with type 2 diabetes and kidney disease: a systematic review. JAMA. 2014;312:2668-2675.
10. Aroda VR, et al. Long-term metformin use and vitamin B12 deficiency in the Diabetes Prevention Program Outcomes Study. J Clin Endocrinol Metab. 2016;101:1754-1761.

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