GLP-1 coverage calculator
What a GLP-1 benefit costs your plan, and the price it would have to be to break even.
The reasoning behind these defaults, and where the published numbers disagree with each other, is in Your mileage may vary. Every input below is yours to change, and your own claims data beats any default here.
Tool
What a GLP-1 benefit costs, and what it returns
For an employer deciding whether to add weight-management coverage. A plan pays for therapy by the month and keeps the employee by the year, and the benefit only arrives for people who are still here and still on it.
Weight management only. This models the anti-obesity indication, not GLP-1s prescribed for type 2 diabetes, where the coverage decision and the cost case are different. Roughly a third of employers currently cover GLP-1s for weight loss, with coverage far more common at large employers than small ones. FDA labeling for Wegovy and Zepbound sets eligibility at BMI 30 or above, or BMI 27 or above with at least one weight-related condition. Plans may tighten that; they cannot loosen it and stay on label.
The eligible population
Covered employees500
Employees enrolled on the plan, not total covered lives
Adults covered per employee1.40
Set this to 1 plus the share of enrolled employees who cover a spouse or adult partner. Cover a spouse on 40% of contracts and the multiplier is 1.40. Children are excluded, because the weight management labels are adult indications with narrow adolescent exceptions. Your enrollment census answers this exactly, and it is the input most worth getting right
Clinically eligible40%
CDC puts BMI 30 or above at 40.3% of US adults. The label also allows 27 or above with a comorbidity, which widens the pool; plans that tighten to 35 or 40 narrow it, with BMI 40 or above at 9.7%
Of those eligible, share who start12%
Eligibility is not utilization. Employers who added coverage in 2023 and 2024 consistently report take-up above their projections
Does the plan capture rebates?Yes
Fully insured and some smaller self-funded plans never see the rebate. If yours does not, the plan is exposed to list
Net cost per member, per year$7,200
After rebates. Employer guidance commonly assumes $600 to $900 per member per month
Who is still here, and still on it
Annual turnover15%
All separations, voluntary and involuntary
Still on therapy after a year66%
Commercial claims studies put one-year persistence between roughly a third and two thirds, improving as shortages eased
The plan, and what you expect back
Total annual health plan spend$7.50M
Expected reduction in plan spend2%
Reduction in total plan spend, not in the treated members' own costs
Medical trend8%
Annual growth in plan spend. Mercer projected 6.7% for 2026 after planned cost-reduction measures and near 9% without them; Aon projected 9.5%. Savings track this rate, which holds the reduction constant as a percentage
Therapy cost trend0%
Net cost per treated member, not total GLP-1 spend. Pharmacy trend of 13% to 15% is largely utilization, which this tool already models separately, so per-member net cost is held flat by default. Set it negative if you expect deflationary pressure on unit cost through rebates or contracting, positive if you expect the opposite. Equal trends on both sides very nearly cancel, so it is the gap between these two that moves the answer
Years to model5
Adults on therapy at any one time19
That is this share of covered adults4.8%
Therapy cost, first year$0
That is this share of plan spend
Therapy cost over 5 years$0
Expected savings if nobody left or stopped$0
Expected savings you actually keep$0
On therapy a full year, from year two onward56%
Reduction needed to break even0%
Reduction needed if nobody left or stopped0%
Net position over 5 years$0
Three ways to close the gap
DOOR 01 · START HERE
Buy it cheaper
$0
DOOR 02
Get more from it
0%
DOOR 03
Cover fewer people
0%
Cumulative therapy cost
Savings you keep
Savings if nobody left or stopped
How this is calculated. A launching program, not one already running. Treated headcount is held constant, so separations and discontinuations are backfilled by new starters who are themselves eligible, and the cost line never falls. Each starter needs a full year on therapy before any benefit is credited, so year one returns nothing. From year two onward the share of the treated population that has held on for a year settles at turnover multiplied by persistence, and stays there. That share is a permanent condition of the program, not something that decays with time.
- What it does not account for. It models no clinical outcome. The expected reduction is your assumption, not a published result, and the tool takes no view on whether it is achievable.
- It ignores stop-loss reimbursement, rebate timing, specialty carve-outs, and any cost sharing borne by the member rather than the plan.
- Employees and lives are different populations. Cost is driven by treated adults, which includes enrolled spouses, while total plan spend covers every life including children. Entering employee headcount without the adult multiplier understates the treated population and flatters every result.
- It assumes backfill starters look like the people they replace. A younger or healthier incoming cohort would take up at a lower rate.
- Turnover among employees on therapy may differ from your overall rate. Nobody has published a reliable figure for that, and this tool does not guess at one.
- The one-year maturation lag is an assumption about when a benefit could show up in claims, not a clinical finding. Both the kept and the unchurned lines carry it, so the gap between them isolates churn alone.
- Therapy cost sits inside total plan spend, so the two are not independent inputs. The expected reduction is read as a reduction in plan spend gross of the therapy, which is why the tool reports what multiple of its own cost the therapy has to return.
Where the defaults come from.
- Eligibility. CDC, National Center for Health Statistics, NHANES August 2021 to August 2023: obesity, BMI 30 or above, 40.3% of adults age 20 and over; severe obesity, BMI 40 or above, 9.7%; overweight, BMI 25 to 29.9, a further 31.7%. An employed population is not the general adult population, so treat these as an upper reference rather than a plan estimate.
- FDA labeling. Wegovy and Zepbound are indicated for chronic weight management at BMI 30 or above, or BMI 27 or above with at least one weight-related condition, as an adjunct to reduced-calorie diet and increased physical activity.
- Employer coverage. A May 2025 survey put 36% of employers covering GLP-1s for weight loss and diabetes. Coverage rises sharply with employer size.
- Net cost. Employer guidance commonly models $600 to $900 per member per month net. One carrier book analysis put the annual increase in pharmacy cost per treated member at roughly $6,540.
- Trend. Mercer projected employer health costs rising 6.7% in 2026 to about $18,500 per worker after planned cost-reduction measures, and close to 9% with no plan changes. Aon projected 9.5%. The 8% default sits inside that band. Pharmacy trend has been running 13% to 15%, but that figure is driven substantially by rising utilization rather than by unit cost, and this tool models utilization on its own sliders, so the therapy cost trend here applies only to net cost per treated member.
- List versus net. Published list prices run near $1,000 to $1,350 per member per month, with Wegovy listed around $1,349. Net after rebates is commonly modeled at $600 to $900. A plan that does not capture the rebate, which includes fully insured arrangements and some smaller self-funded ones, is exposed to something much closer to list, and the break-even doors move accordingly.
- Persistence. Commercial claims analyses of members without diabetes report one-year persistence between roughly 32% and 63% depending on year of initiation. Two-year and three-year figures are substantially lower.
- The direction of the evidence. A December 2025 market review concluded the evidence is unanimous that GLP-1s currently increase total healthcare spending for employers, with drug costs exceeding reductions in other medical costs across the three to four years most workers stay on a given plan. EBRI found no evidence that savings fully offset GLP-1 prices. Published effects are measured on treated members' own medical costs, not on total plan spend, and the denominators differ by roughly the treated share.
Before you rely on any of this.
- Nothing you type leaves your browser. There is no account, no submission, no analytics on the inputs, and nothing is stored or transmitted. Close the tab and the numbers are gone.
- This is not an actuarial opinion and must not be used as one. It is an illustration built on assumptions you supply. It is not suitable for rate setting, funding decisions, reserve estimates, financial reporting, or anything requiring certification. Your actuary, carrier, or consultant should see any number you intend to act on.
- It is not a coverage recommendation. It takes no position on whether a plan should cover these medications, or for whom. That decision involves clinical, legal, and workforce considerations this tool does not model.
- Coverage design carries legal exposure this tool does not address. Eligibility criteria, exclusions, and prior authorisation rules for weight management drugs can raise questions under federal and state law. Those belong with benefits counsel, not with a calculator.
- It is written for plan sponsors, not patients. If you take one of these medications or are considering it, nothing here bears on your treatment. Talk to your clinician.
- Figures are current to August 2026. Pricing, persistence data, and coverage practice in this category have all moved substantially inside twelve months, and the defaults will date faster than the arithmetic will.
Fringe Theory is independent and unaffiliated. Views expressed are my own and do not represent those of my employer. Nothing here is legal, tax, medical, or investment advice.