Free reference tools for medical billing and coding: search common ICD-10 and CPT codes, check nurse staffing ratios, calculate weight-based doses, and estimate billing.
Estimated patient responsibility
Four quick references for coders, students and billing staff.
Search common ICD-10 diagnosis and CPT procedure codes instantly.
See my numbers →Compare your unit's nurse-to-patient ratio to recommended levels.
See my numbers →Weight-based dose and volume to administer from concentration.
See my numbers →Estimate insurance and patient responsibility on a CPT code.
See my numbers →A charge on paper and the amount a patient actually owes are two different calculations, and most of the gap comes down to three inputs. The first is the CPT code itself: a routine office visit (99213) carries a reference fee around $110 in our sample set, while a new-patient visit that runs 45 to 59 minutes (99204) sits closer to $234. Lab work is cheaper across the board; a complete blood count (85025) lists at $11.
The second input is the payer type, and this is where most of the swing happens. Medicare pays roughly 80% of the allowed amount, Medicaid closer to 65%, and private insurance around 95%, at least in the simplified model this site uses. An uninsured patient is billed the full 100%, which is the single biggest reason self-pay bills look so much larger than an insured bill for the identical CPT code. The third input is the patient's own responsibility split, coinsurance, copay, or deductible, which determines how the adjusted total divides between payer and patient.
The same logic shows up outside billing. A dose calculation depends on patient weight, a dose-per-kilogram figure, and the concentration of the drug on hand; change any one of those and the volume to administer changes with it. A staffing ratio depends on patient count, nurses on shift, and the unit's recommended ratio, commonly 1:2 in an ICU and 1:6 on a general Med-Surg floor. Different domains, same shape: a few clean inputs, run through a fixed formula, produce a number worth sanity-checking rather than trusting blind.
Take a 99214 office visit, an established-patient appointment lasting 30 to 39 minutes. The reference fee is $168. Run it through Medicaid's 65% factor and the adjusted total drops to $109.20. If the patient's coinsurance share is set at 20%, the patient owes about $21.84 and the payer covers the remaining $87.36. Swap Medicaid for private insurance at 95% and the adjusted total climbs to $159.60, with the patient's 20% share now closer to $31.92, because the higher-paying plan and the higher-priced base fee both push the number up, not down. Coverage percentage and patient share pull the final number in different directions, which is exactly why two patients with the same code and same visit can see very different bills.
The dosage tool runs a parallel chain. A 70 kg patient prescribed 5 mg/kg needs a total dose of 350 mg. If the medication on hand is concentrated at 10 mg/mL, the volume to draw up is 35 mL, a straightforward division once the unit conversions are sorted out. Get the weight unit wrong, kilograms versus pounds, and the total dose is off by more than double. That is the kind of error this tool is built to catch before it happens, not after.
These tools are built for learning and quick reference, not for anything that touches a real claim, a real chart, or a real patient. The line is worth stating plainly. If you are coding or billing an actual encounter, verify every ICD-10 and CPT code against the current official code sets and the payer's own published rules; this site's code list is a curated sample, not the full 70,000-plus ICD-10 set or the 10,000-plus CPT codes in circulation. If a dosage question involves an actual patient, the answer comes from a pharmacist and the prescribing information, never from a browser tool, no matter how carefully the formula is built. And if a staffing ratio decision affects real patient assignments, hospital policy, state law (California mandates specific ratios; most states do not), and clinical acuity outrank any benchmark number a calculator can produce.
Where these tools earn their keep is in the gap before that point: a student memorizing common codes, a new biller trying to understand why a bill looks the way it does, a charge nurse doing quick math before a formal staffing review. Recheck the source references periodically, since fee schedules, coverage rules and staffing guidance all shift over time and a bookmarked page does not update itself.
