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Coinsurance Target Calculator

Coinsurance clauses require you to insure to a percentage of replacement cost — typically 80% or 90%. Under-insure and the insurer applies a penalty proportional to the gap. This calculator computes required coverage, the gap, and what a claim would actually pay out after the coinsurance penalty.

Replacement cost

Current coverage limit

Coinsurance %

Hypothetical loss

Deductible

Required coverage to meet coinsurance

$1,600,000

Coinsurance factor

87.50%

Penalty applied to claim

$37,500

Actual claim payout (after ded)

$252,500

Gap below required

$200,000

How the math works

Coinsurance requires you to insure to a percentage of replacement cost — typically 80% or 90%. Underinsure and the insurer applies a penalty to every claim: claim × (coverage / required). An 80% coinsurance property insured at 70% of RC takes a 12.5% cut on every claim.

Always insure to or above the coinsurance threshold. The premium savings from under-insurance are tiny compared to the penalty on a real claim.

Editorial noteMaintained by EveryCalc - Reviewed June 2026

EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.

Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.

Learn more about our review process on the EveryCalc methodology page.

How this calculator works

What this page estimates

This Coinsurance Target Calculator is built to give a quick, browser-based estimate for coinsurance target. Coinsurance clauses require you to insure to a percentage of replacement cost — typically 80% or 90%. Under-insure and the insurer applies a penalty proportional to the gap. This calculator computes required coverage, the gap, and what a claim would actually pay out after the coinsurance penalty. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.

Calculation approach

The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For finance tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.

Example workflow

For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.

Practical checks

Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
Run a low, base, and high case when the inputs are estimates.
Check the related calculators below when the next decision depends on a different assumption.

How to interpret the coinsurance target result

Best use

Use the result as a planning number for comparing payments, rates, returns, tax reserves, or cash-flow choices before you request a quote or make a commitment.

Cross-check

Compare the answer with the contract, lender estimate, tax form, brokerage statement, payroll record, or invoice that will control the real-world outcome.

Watch for

Do not rely on a single optimistic rate, return, or fee assumption. Money pages work best when you run low, base, and high cases and keep professional advice separate from the estimate.

This page belongs to the Finance calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.

Before relying on this coinsurance target estimate

Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.

Confirm source numbers

Match balances, rates, fees, taxes, income, and payment dates against the lender quote, payroll record, tax form, statement, invoice, or contract.

Separate cash flow from total cost

A lower monthly payment can still cost more over time if fees, interest, taxes, or a longer term are hidden in the structure.

Run conservative cases

Test at least one higher-cost or lower-return case before using the output for a purchase, refinance, investment, loan, or tax decision.

Rerun this page when the rate, price, term, fee, tax rule, income, expense, or expected holding period changes.

How to Use

Enter replacement cost and current coverage limit.
Enter coinsurance percentage from your policy (usually 80 or 90%).
Enter hypothetical loss and deductible.
Read required coverage, coinsurance factor, and claim payout.

Frequently Asked Questions

How coinsurance penalty works?

Formula: claim × (actual coverage / required coverage). If required is $1.6M but you carry $1.4M, your factor = 87.5%. A $300K claim pays $262.5K before deductible instead of $300K.

How to avoid penalty?

Insure at 100% of RC even if coinsurance is 80%. Or use 'agreed value' endorsement that waives coinsurance in exchange for a pre-agreed valuation.

Replacement cost vs ACV?

Replacement cost = what it costs to rebuild new. Actual cash value (ACV) = RC minus depreciation. RC is more expensive premium but much better coverage at claim time. For income property, always use RC.