Carrier websites make plan comparison deliberately hard: different data caps, different line-count discounts, autopay conditions, and taxes that only show up at checkout. This calculator strips all of that down to two numbers — cost per line and cost per GB — so you can compare any two or three plans on equal footing, whether they're single-line, family plans, or a mix of major carriers and budget MVNOs.
Why the sticker price is misleading
A $200/month plan and a $50/month plan sound wildly different until you notice one covers 4 lines and the other covers 1. The advertised monthly price is the least useful number for comparison purposes — it bundles together line count, data allowance, and promotional discounts that expire after 12 or 24 months. Cost per line and cost per GB strip those variables out, letting you compare a family plan against a single-line plan, or a data-heavy plan against a light-usage plan, on the same footing.
Hidden fees that inflate the real bill
Two costs almost never appear in headline pricing: the autopay penalty (many carriers add back $5–$10 per line if you don't enroll in autopay billing) and taxes & regulatory fees, which vary by state but commonly add 10–15% to the bill (see the FCC's guide to telephone bill fees). This calculator lets you toggle both so the numbers you compare match what actually lands on your statement, not just the number in the ad.
Why cost per GB matters more than the sticker price
Unlimited plans aren't automatically the best value — they're the best value only if you actually use enough data to justify the premium. If your typical usage is 5 GB a month, a $70 unlimited plan and a $25 plan with a 15 GB cap deliver identical service for you, but one costs 3x more. The Data Needs Fit tab on this page compares your real monthly usage against each plan's allowance so you can see whether you're paying for headroom you'll never touch.
MVNO vs. major carrier: what you're really trading off
MVNOs (Mobile Virtual Network Operators) like Mint Mobile, Visible, and Google Fi lease network capacity from Verizon, AT&T, or T-Mobile and typically charge 40–60% less for equivalent coverage. The trade-off is network deprioritization — during congestion (a packed stadium, a holiday weekend in a busy area), the host carrier's own postpaid customers get priority. For most users in typical suburban and urban areas, day-to-day service is indistinguishable from the major carrier, which is why MVNO switching is one of the largest guaranteed savings available in a household budget with essentially no downside for light-to-moderate users.