Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

T. Rowe Price Index Trust, Inc.

Prospectus Date

rr_ProspectusDate

May 01, 2015

Supplement [Text Block]

trpiti_SupplementTextBlock

T. Rowe Price Total Equity Market Index Fund

Supplement to Summary Prospectus Dated May 1, 2015

To reflect the lowering of the fund's management fee from 0.35% to 0.30% effective August 1, 2015, the fee table and expense example on page 1 are revised as follows:

Fees and Expenses of the Fund

Shareholder fees (fees paid directly from your investment)
Maximum sales charge (load) imposed on purchases	NONE
Maximum deferred sales charge (load)	NONE
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	0.50%
Maximum account fee	$20a
Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)
Management fees	0.30%b
Distribution and service (12b-1) fees	0.00%
Other expenses	0.00%
Total annual fund operating expenses	0.30%b

a Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

b Restated to reflect current fees.

Example This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 year	3 years	5 years	10 years
$31	$97	$169	$381

T. Rowe Price Total Equity Market Index Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

trpiti_SupplementTextBlock

T. Rowe Price Total Equity Market Index Fund

Supplement to Summary Prospectus Dated May 1, 2015

To reflect the lowering of the fund's management fee from 0.35% to 0.30% effective August 1, 2015, the fee table and expense example on page 1 are revised as follows:

Fees and Expenses of the Fund

Shareholder fees (fees paid directly from your investment)
Maximum sales charge (load) imposed on purchases	NONE
Maximum deferred sales charge (load)	NONE
Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)	0.50%
Maximum account fee	$20a
Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)
Management fees	0.30%b
Distribution and service (12b-1) fees	0.00%
Other expenses	0.00%
Total annual fund operating expenses	0.30%b

a Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

b Restated to reflect current fees.

Example This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

1 year	3 years	5 years	10 years
$31	$97	$169	$381

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Fees and Expenses of the Fund

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses
(expenses that you pay each year as a
percentage of the value of your investment)

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

Restated to reflect current fees.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

T. Rowe Price Total Equity Market Index Fund | T. Rowe Price Total Equity Market Index Fund

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load)

rr_MaximumDeferredSalesChargeOverOther

none

Redemption fee (as a percentage of amount redeemed on shares held for 90 days or less)

rr_RedemptionFeeOverRedemption

0.50%

Maximum account fee

^[1]

rr_MaximumAccountFee

$ 20

Management fees

^[2]

rr_ManagementFeesOverAssets

0.30%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

none

Total annual fund operating expenses

^[2]

rr_ExpensesOverAssets

0.30%

1 year

rr_ExpenseExampleYear01

$ 31

3 years

rr_ExpenseExampleYear03

97

5 years

rr_ExpenseExampleYear05

169

10 years

rr_ExpenseExampleYear10

$ 381

[1] Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee.

[2] Restated to reflect current fees.