v3.26.1
Shareholder Report
 6 Months Ended
Mar. 31, 2026
USD ($)
$ / shares
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Build Funds Trust
Entity Central Index Key 0001875710
Entity Investment Company Type N-1A
Document Period End Date Mar. 31, 2026
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
Build Bond Innovation ETF  
Shareholder Report [Line Items]  
Fund Name Build Bond Innovation ETF
Class Name Build Bond Innovation ETF
Trading Symbol BFIX
Security Exchange Name NYSE
Annual or Semi-Annual Statement [Text Block] This Semi-Annual Shareholder Report contains important information about the Build Bond Innovation ETF (the “Fund”) for the period of  October 1, 2025, to March 31, 2026.
Additional Information [Text Block] You can find additional information about the Fund at https://getbuilding.com/etfs/bfix/. You can also request this information by contacting us at 1-833-852-8453.
Additional Information Phone Number 1-833-852-8453
Additional Information Website https://getbuilding.com/etfs/bfix/
Expenses [Text Block]
WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment)
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment*
Build Bond Innovation ETF
$23
0.45%
[1]
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.45%
Net Assets $ 12,657,610
Holdings Count | $ / shares 126
Advisory Fees Paid, Amount $ 26,173
Investment Company Portfolio Turnover 34.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of March 31, 2026)
Net Assets
$12,657,610
Number of Holdings
126
Total Advisory Fee
$26,173
Portfolio Turnover
34%
30-Day SEC Yield
3.50%
Holdings [Text Block]
WHAT DID THE FUND INVEST IN? (as of March 31, 2026)
Top 10 Issuers
(% of net assets)
United States Treasury Note/Bond
60.8%
Essex Portfolio LP
2.2%
Lowe’s Cos., Inc.
1.7%
AutoZone, Inc.
1.4%
Toyota Motor Credit Corp.
1.3%
AT&T, Inc.
1.2%
Huntington Ingalls Industries, Inc.
1.0%
Marriott International, Inc.
1.0%
AvalonBay Communities, Inc.
1.0%
Oracle Corp.
1.0%
Top Sectors
(% of net assets)
Public Administration
60.8%
Manufacturing
10.5%
Finance and Insurance
5.7%
Retail Trade
4.9%
Real Estate and Rental and Leasing
4.3%
Information
2.4%
Utilities
2.0%
Mining, Quarrying, and Oil and Gas Extraction
1.7%
Accommodation and Food Services
1.4%
Cash & Other
6.3%
Updated Prospectus Web Address https://getbuilding.com/etfs/bfix/
[1]
* Annualized