How to use this calculator
- Enter your current balance and monthly contributions.
- Set the projection period and your interest estimate.
- Add expected visits, copays, prescriptions, and other charges.
- Fill Plan A details, including amounts already paid.
- Optional: enable Plan B to compare total annual cost.
- Add a bill to estimate a monthly payment schedule.
- Press Submit to view results above the form.
- Use CSV or PDF buttons to export the summary.
Formula used
1) Savings projection (monthly compounding)
FV = PV·(1+r)n + PMT·(( (1+r)n − 1 ) / r), where r = annual_rate/12 and n = months.
2) Out-of-pocket estimate (simplified)
Patient cost ≈ min(OOP remaining, service cost + copays). Service cost applies deductible first, then coinsurance on remaining allowed charges.
3) Payment plan (amortized loan)
Payment = P·(r / (1 − (1+r)−n)), where r = APR/12 and n = months.
Example data table
| Input item | Example value | What it represents |
|---|---|---|
| Current balance | $1,500.00 | Starting savings available for qualified expenses. |
| Monthly contributions | $250.00 | Employee + employer monthly deposits. |
| Annual interest | 2.50% | Estimated growth on the account balance. |
| Other allowed charges | $3,000.00 | Procedures, labs, imaging, outpatient services. |
| Plan A: deductible / coinsurance | $1,600 / 20% | How costs are shared after deductible. |
| Bill amount / term | $1,200 / 12 mo | Optional monthly payment estimate for a bill. |
| Typical output | Projected balance & plan totals | Ending balance, OOP estimate, annual cost, payments. |
Tip: Replace example values with your plan documents and realistic usage assumptions.
Contribution and balance forecasting
This calculator projects a health savings balance using monthly compounding. Start with an opening balance and add employee and employer deposits each month. For example, a $1,500 balance with $250 monthly deposits at 2.50% annual interest grows to about $4,560 after 12 months. The projection helps align deposits with predictable costs, not just annual targets today.
Estimating annual plan costs
Plan costs combine premiums and expected out-of-pocket spending. The tool applies the deductible, then coinsurance to allowed charges, and caps the result at the out-of-pocket maximum. If allowed charges are $3,000, a $1,600 deductible and 20% coinsurance produce a service share near $1,880 before copays. Add visit and prescription copays for a fuller estimate.
Comparing Plan A and Plan B
When you enable Plan B, the same assumptions are priced under a second premium, deductible, coinsurance, and out-of-pocket maximum. A higher premium can still win if it lowers expected out-of-pocket costs. The output shows the cheaper plan and the annual difference for budgeting and renewal decisions. It also highlights how caps change risk overall.
Funding adequacy and gap planning
A key metric is the coverage ratio: projected savings divided by the Plan A out-of-pocket estimate. A ratio above 1.00× suggests the account could cover expected out-of-pocket costs, while a lower ratio indicates a potential gap. If the gap is $420 over 12 months, the tool suggests adding about $35 per month. This turns uncertainty into a clear contribution adjustment.
Payment planning for large bills
Unexpected bills may need structured payments. The payment module estimates an amortized monthly payment from the bill amount, APR, and term. A $1,200 balance at 8.0% APR over 12 months is about $104 per month, with roughly $48 of interest. Pairing the payment estimate with your savings projection helps you decide whether to pay from savings, spread payments, or increase contributions.
FAQs
1) What does “other allowed charges” mean here?
Enter the estimated total of services that are subject to deductible and coinsurance, like labs, imaging, procedures, and outpatient care. Keep fixed visit or prescription copays out of this field to avoid double counting.
2) How is out-of-pocket capped?
The calculator estimates your out-of-pocket total, then limits it to the remaining out-of-pocket maximum after subtracting what you already paid. Premiums are added separately because they are not part of the out-of-pocket limit.
3) Can I use this for any health savings account?
Yes, for planning. The projection assumes monthly contributions and a constant interest rate. If your account has tiered rates, fees, or investment swings, use an average rate and treat results as a directional estimate.
4) How should I set the tax rate?
Use your approximate marginal tax rate for contributions you make through payroll. The tax-savings figure is an estimate based only on employee contributions, and it does not replace professional tax advice.
5) What if my plan uses copays after the deductible?
Plans vary. This tool treats copays as out-of-pocket and applies deductible and coinsurance to the “other allowed charges” field. If your plan applies different rules, adjust your inputs so the totals match your plan’s expected behavior.
6) Does the payment plan represent a loan?
It models an amortized payment schedule using APR and term, similar to a financed balance. If your provider offers interest-free installments, set APR to 0% to see a simple monthly split.
Disclaimer
This tool provides estimates for planning and comparison. Health plan rules vary by carrier and region. Confirm details with your plan documents and providers before making decisions.