Tuition and Fees
Texas Resident Guaranteed Tuition & Fees 2026 - 2027
Undergraduate (Fall and Spring - 16 Week and 8 Week and 5 Week Parts Term)
| Hours | Tuition1 | Designated Tuition2 | International Ed Fee | Rec Sports Fee | University Services Fee | Student Services Fee | Athletics Fee | Student Union Fee | Total |
|---|---|---|---|---|---|---|---|---|---|
| 1 | $50.00 | $230.36 | $3.00 | $100.00 | $299.53 | $15.00 | $10.50 | $100.00 | $808.39 |
| 2 | $100.00 | $293.31 | $3.00 | $100.00 | $402.91 | $30.00 | $21.00 | $100.00 | $1,050.22 |
| 3 | $150.00 | $390.68 | $3.00 | $100.00 | $402.91 | $30.00 | $31.50 | $100.00 | $1,326.47 |
| 4 | $200.00 | $510.74 | $3.00 | $100.00 | $609.67 | $60.00 | $42.00 | $100.00 | $1,625.41 |
| 5 | $250.00 | $630.80 | $3.00 | $100.00 | $713.05 | $75.00 | $52.50 | $100.00 | $1,924.35 |
| 6 | $300.00 | $750.86 | $3.00 | $100.00 | $816.43 | $90.00 | $63.00 | $100.00 | $2,223.29 |
| 7 | $350.00 | $870.92 | $3.00 | $100.00 | $919.81 | $105.00 | $73.50 | $100.00 | $2,522.23 |
| 8 | $400.00 | $990.98 | $3.00 | $100.00 | $1,023.19 | $120.00 | $84.00 | $100.00 | $2,821.17 |
| 9 | $450.00 | $1,111.04 | $3.00 | $100.00 | $1,126.57 | $135.00 | $94.50 | $100.00 | $3,120.11 |
| 10 | $500.00 | $1,231.10 | $3.00 | $100.00 | $1,229.95 | $150.00 | $105.00 | $100.00 | $3,419.05 |
| 11 | $550.00 | $1,351.16 | $3.00 | $100.00 | $1,347.88 | $150.00 | $115.50 | $100.00 | $3,717.54 |
| 12 | $600.00 | $1,471.22 | $3.00 | $100.00 | $1,465.81 | $150.00 | $126.00 | $100.00 | $4,016.03 |
| 13 | $650.00 | $1,591.28 | $3.00 | $100.00 | $1,583.74 | $150.00 | $126.00 | $100.00 | $4,304.02 |
| 14 | $700.00 | $1,711.34 | $3.00 | $100.00 | $1,701.67 | $150.00 | $126.00 | $100.00 | $4,592.01 |
| 15 | $750.00 | $1,831.40 | $3.00 | $100.00 | $1,819.60 | $150.00 | $126.00 | $100.00 | $4,880.00 |
| 16 | $800.00 | $1,831.40 | $3.00 | $100.00 | $1,937.53 | $150.00 | $126.00 | $100.00 | $5,047.93 |
| 17 | $850.00 | $1,831.40 | $3.00 | $100.00 | $2,055.46 | $150.00 | $126.00 | $100.00 | $5,215.86 |
| 18 | $900.00 | $1,831.40 | $3.00 | $100.00 | $2,173.39 | $150.00 | $126.00 | $100.00 | $5,383.79 |
| 19 | $950.00 | $1,831.40 | $3.00 | $100.00 | $2,291.32 | $150.00 | $126.00 | $100.00 | $5,551.72 |
| 20 | $1,000.00 | $1,831.40 | $3.00 | $100.00 | $2,409.25 | $150.00 | $126.00 | $100.00 | $5,719.65 |
- 1
Undergraduate resident rate students who have attempted more than 30 credit hours in excess of the required hours for their degree program will be charged tuition at a rate of $150 per semester credit hour instead of $50 per semester credit hour. This higher tuition rate will go into effect the next enrolled term after the student reaches this threshold.
The University’s reinstatement fee is $363. The 3-Peat fee is $100 per semester credit hour.
The University reserves the right to change fees upon board approval.
Minimum Tuition: $50.00
- 2
15 semester credit hours or more pay $1604.17/SEM based on flat rate at 15 SCH’s
Add $50.00 tuition and $117.93 University Services fee for each semester credit hour over 20. Other fees remain the same.
- 3
Total includes a Student Union Fee of $100.00 per semester.
Undergraduate (Summer - 10 Weeks, 5 or 8 Week Parts of Term, and Maymester)
| Hours | Tuition1 | Designated Tuition2 | International Ed Fee | Rec Sports Fee | University Services Fee | Student Services Fee | Athletics Fee | Student Union Fee | Total |
|---|---|---|---|---|---|---|---|---|---|
| 1 | $50.00 | $194.03 | $3.00 | $50.00 | $295.84 | $15.00 | $ 10.50 | $100.00 | $ 668.37 |
| 2 | $100.00 | $245.55 | $3.00 | $100.00 | $399.08 | $30.00 | $21.00 | $100.00 | $998.63 |
| 3 | $150.00 | $329.76 | $3.00 | $100.00 | $502.32 | $45.00 | $31.50 | $100.00 | $1,261.58 |
| 4 | $200.00 | $435.75 | $3.00 | $100.00 | $605.56 | $60.00 | $42.00 | $100.00 | $1,546.31 |
| 5 | $250.00 | $541.74 | $3.00 | $100.00 | $708.80 | $75.00 | $52.50 | $100.00 | $1,831.04 |
| 6 | $300.00 | $647.73 | $3.00 | $100.00 | $812.04 | $90.00 | $63.00 | $100.00 | $2,115.77 |
| 7 | $350.00 | $753.82 | $3.00 | $100.00 | $915.28 | $105.00 | $73.50 | $100.00 | $2,400.50 |
| 8 | $400.00 | $859.71 | $3.00 | $100.00 | $1,018.52 | $120.00 | $84.00 | $100.00 | $2,685.23 |
| 9 | $450.00 | $965.70 | $3.00 | $100.00 | $1,121.76 | $135.00 | $94.50 | $100.00 | $2,969.96 |
| 10 | $500.00 | $1071.69 | $3.00 | $100.00 | $1,225.00 | $150.00 | $105.00 | $100.00 | $3,254.69 |
| 11 | $550.00 | $1,177.68 | $3.00 | $100.00 | $1,343.25 | $150.00 | $115.50 | $100.00 | $3,539.43 |
| 12 | $600.00 | $1,283.67 | $3.00 | $100.00 | $1,461.50 | $150.00 | $126.00 | $100.00 | $3,824.17 |
| 13 | $650.00 | $1,389.66 | $3.00 | $100.00 | $1,579.75 | $150.00 | $126.00 | $100.00 | $4,098.41 |
| 14 | $700.00 | $1,495.65 | $3.00 | $100.00 | $1,698.00 | $150.00 | $126.00 | $100.00 | $4,372.65 |
| 15 | $750.00 | $1,601.64 | $3.00 | $100.00 | $1,816.25 | $150.00 | $126.00 | $100.00 | $4,646.89 |
| 16 | $800.00 | $1,604.17 | $3.00 | $100.00 | $1,934.50 | $150.00 | $126.00 | $100.00 | $4,817.67 |
| 17 | $850.00 | $1,601.64 | $3.00 | $100.00 | $2,052.75 | $150.00 | $126.00 | $100.00 | $4,985.92 |
| 18 | $900.00 | $1,601.64 | $3.00 | $100.00 | $2,171.00 | $150.00 | $126.00 | $100.00 | $5,154.17 |
| 19 | $950.00 | $1,601.64 | $3.00 | $100.00 | $2,289.25 | $150.00 | $126.00 | $100.00 | $5,322.42 |
| 20 | $1,000.00 | $1,601.64 | $3.00 | $100.00 | $2,407.50 | $150.00 | $126.00 | $100.00 | $5,490.67 |
- 1
Undergraduate resident rate students who have attempted more than 30 credit hours in excess of the required hours for their degree program will be charged tuition at a rate of $150 per semester credit hour instead of $50 per semester credit hour. This higher tuition rate will go into effect the next enrolled term after the student reaches this threshold.
The University’s reinstatement fee is $363. The 3-Peat fee is $100 per semester credit hour.
The University reserves the right to change fees upon board approval.
Minimum Tuition: $50.00
- 2
15 semester credit hours or more pay $1,601.64/SEM based on flat rate at 15 SCH’s
Add $50.00 tuition and $118.25 University Services fee for each semester credit hour over 20. Other fees remain the same.
- 3
Total includes a Student Union Fee of $50.00 per semester.
Texas Resident Guaranteed Tuition & Fees 2021 - 2025
(Fall and Spring - 16 Week and 8 Week and 5 Week Parts of Term)
| Hours | Tuition1 | Designated Tuition2 | International Ed Fee | Rec Sports Fee | University Services Fee | Student Services Fee | Athletics Fee | Student Union Fee | Total |
|---|---|---|---|---|---|---|---|---|---|
| 1 | $50.00 | $230.36 | $3.00 | $100.00 | $299.53 | $15.00 | $10.50 | $100.00 | $808.39 |
| 2 | $100.00 | $293.31 | $3.00 | $100.00 | $402.91 | $30.00 | $21.00 | $100.00 | $1,050.22 |
| 3 | $150.00 | $390.68 | $3.00 | $100.00 | $506.29 | $45.00 | $31.50 | $100.00 | $1,326.47 |
| 4 | $200.00 | $510.74 | $3.00 | $100.00 | $609.67 | $60.00 | $42.00 | $100.00 | $1,625.41 |
| 5 | $250.00 | $630.80 | $3.00 | $100.00 | $713.05 | $75.00 | $52.50 | $100.00 | $1,924.35 |
| 6 | $300.00 | $750.86 | $3.00 | $100.00 | $816.43 | $90.00 | $63.00 | $100.00 | $2,223.29 |
| 7 | $350.00 | $870.92 | $3.00 | $100.00 | $919.81 | $105.00 | $73.50 | $100.00 | $2,522.23 |
| 8 | $400.00 | $990.98 | $3.00 | $100.00 | $1023.19 | $120.00 | $94.50 | $100.00 | $3,120.11 |
| 9 | $450.00 | $1,111.04 | $3.00 | $100.00 | $1,126.57 | $135.00 | $94.50 | $100.00 | $3,120.11 |
| 10 | $500.00 | $1,231.10 | $3.00 | $100.00 | $1,229.95 | $150.00 | $105.00 | $100.00 | $3,419.05 |
| 11 | $550.00 | $1,351.16 | $3.00 | $100.00 | $1,347.88 | $150.00 | $115.50 | $100.00 | $3,717.54 |
| 12 | $600.00 | $1,471.22 | $3.00 | $100.00 | $1,465.81 | $150.00 | $126.00 | $100.00 | $4,016.03 |
| 13 | $650.00 | $1,591.28 | $3.00 | $100.00 | $1,583.74 | $150.00 | $126.00 | $100.00 | $4,304.02 |
| 14 | $700.00 | $1,711.34 | $3.00 | $100.00 | $1,701.67 | $150.00 | $126.00 | $100.00 | $4,592.01 |
| 15 | $750.00 | $1,831.40 | $3.00 | $100.00 | $1,819.60 | $150.00 | $126.00 | $100.00 | $4,880.00 |
| 16 | $800.00 | $1,831.40 | $3.00 | $100.00 | $1,937.53 | $150.00 | $126.00 | $100.00 | $5,047.93 |
| 17 | $850.00 | $1,831.40 | $3.00 | $100.00 | $2,055.46 | $150.00 | $126.00 | $100.00 | $5,215.86 |
| 18 | $900.00 | $1,831.40 | $3.00 | $100.00 | $2,173.39 | $150.00 | $126.00 | $100.00 | $5,383.79 |
| 19 | $950.00 | $1,831.40 | $3.00 | $100.00 | $2,291.32 | $150.00 | $126.00 | $100.00 | $5,551.72 |
| 20 | $1,000.00 | $1,831.40 | $3.00 | $100.00 | $2,409.25 | $150.00 | $126.00 | $100.00 | $5,719.65 |
- 1
Undergraduate resident rate students who have attempted more than 30 credit hours in excess of the required hours for their degree program will be charged tuition at a rate of $150 per semester credit hour instead of $50 per semester credit hour. This higher tuition rate will go into effect the next enrolled term after the student reaches this threshold.
The University’s reinstatement fee is $363. The 3-Peat fee is $100 per semester credit hour.
The University reserves the right to change fees upon board approval.
Minimum Tuition: $50.00
- 2
15 semester credit hours or more pay $1,831.40/SEM based on flat rate at 15 SCH’s
Add $50.00 tuition and $117.93 University Services fee for each semester credit hour over 20. Other fees remain the same.
- 3
Total includes a Student Union Fee of $100 per semester.
New Undergraduate for Fall 2026, Spring 2027 or Summer 2027 (Summer - 10 Week, 5 or 8 Week Parts of Term, and Maymester)
| Hours | Tuition1 | Designated Tuition2 | International Ed Fee | Rec Sports Fee | University Services Fee | Student Services Fee | Athletics Fee | Student Union Fee | Total |
|---|---|---|---|---|---|---|---|---|---|
| 1 | $50.00 | $230.36 | $3.00 | $100.00 | $299.53 | $15.00 | $10.50 | $100.00 | $808.39 |
| 2 | $100.00 | $293.31 | $3.00 | $100.00 | $402.91 | $30.00 | $21.00 | $100.00 | $1,050.22 |
| 3 | $150.00 | $390.68 | $3.00 | $100.00 | $506.29 | $45.00 | $31.50 | $100.00 | $1,326.47 |
| 4 | $200.00 | $510.74 | $3.00 | $100.00 | $609.67 | $60.00 | $42.00 | $100.00 | $1,625.41 |
| 5 | $250.00 | $630.80 | $3.00 | $100.00 | $713.05 | $75.00 | $52.50 | $100.00 | $1,924.35 |
| 6 | $300.00 | $750.86 | $3.00 | $100.00 | $816.43 | $90.00 | $63.00 | $100.00 | $2,223.29 |
| 7 | $350.00 | $870.92 | $3.00 | $100.00 | $919.81 | $105.00 | $73.50 | $100.00 | $2,522.23 |
| 8 | $400.00 | $990.98 | $3.00 | $100.00 | $1,023.19 | $120.00 | $84.00 | $100.00 | $2,821.17 |
| 9 | $450.00 | $1,111.04 | $3.00 | $100.00 | $1,126.57 | $135.00 | $94.50 | $100.00 | $3,120.11 |
| 10 | $500.00 | $1,231.10 | $3.00 | $100.00 | $1,229.95 | $150.00 | $105.00 | $100.00 | $3,419.05 |
| 11 | $550.00 | $1,351.16 | $3.00 | $100.00 | $1,347.88 | $150.00 | $115.50 | $100.00 | $3,717.54 |
| 12 | $600.00 | $1,471.22 | $3.00 | $100.00 | $1,465.81 | $150.00 | $126.00 | $100.00 | $4,016.03 |
| 13 | $650.00 | $1,591.28 | $3.00 | $100.00 | $1,583.74 | $150.00 | $126.00 | $100.00 | $4,304.02 |
| 14 | $700.00 | $1,711.34 | $3.00 | $100.00 | $1,701.67 | $150.00 | $126.00 | $100.00 | $4,592.01 |
| 15 | $750.00 | $1,822.72 | $3.00 | $100.00 | $1,819.60 | $150.00 | $126.00 | $100.00 | $4,880.00 |
| 16 | $800.00 | $1,831.40 | $3.00 | $100.00 | $1,937.53 | $150.00 | $126.00 | $100.00 | $5,047.93 |
| 17 | $850.00 | $1,831.40 | $3.00 | $100.00 | $2,055.46 | $150.00 | $126.00 | $100.00 | $5,215.86 |
| 18 | $900.00 | $1,831.40 | $3.00 | $100.00 | $2,173.39 | $150.00 | $126.00 | $100.00 | $5,383.79 |
| 19 | $950.00 | $1,831.40 | $3.00 | $100.00 | $2,291.32 | $150.00 | $126.00 | $100.00 | $5,551.72 |
| 20 | $1,000.00 | $1,831.40 | $3.00 | $100.00 | $2,409.25 | $150.00 | $126.00 | $100.00 | $5,719.65 |
- 1
Undergraduate resident rate students who have attempted more than 30 credit hours in excess of the required hours for their degree program will be charged tuition at a rate of $150 per semester credit hour instead of $50 per semester credit hour. This higher tuition rate will go into effect the next enrolled term after the student reaches this threshold.
The University’s reinstatement fee is $363.00. The 3-Peat fee is $100 per semester credit hour.
The University reserves the right to change fees upon board approval.
Minimum Tuition: $50.00
- 2
15 semester credit hours or more pay $1,822.72/SEM based on flat rate at 15 SCH’s
Add $50.00 tuition and $118.25 University Services fee for each semester credit hour over 20. Other fees remain the same.
- 3
Total includes a Student Union Fee of $100.00 per semester.
Non-Texas Resident Fees 2025-2026
Undergraduate (Fall and Spring - 16 Week and 5 or 8 Week Parts of Term)
| Hours | Tuition1 | Designated Tuition2 | International Ed Fee | Rec Sports Fee | University Services Fee | Student Services Fee | Athletics Fee | Student Union Fee | Total |
|---|---|---|---|---|---|---|---|---|---|
| 1 | $478.00 | $176.26 | $3.00 | $100.00 | $273.28 | $15.00 | $10.50 | $100.00 | $1,156.04 |
| 2 | $956.00 | $328.80 | $3.00 | $100.00 | $378.96 | $30.00 | $21.00 | $100.00 | $1,917.76 |
| 3 | $1,434.00 | $481.34 | $3.00 | $100.00 | $484.64 | $45.00 | $31.50 | $100.00 | $2,679.48 |
| 4 | $1,912.00 | $633.88 | $3.00 | $100.00 | $590.32 | $60.00 | $42.00 | $100.00 | $3,441.20 |
| 5 | $2,390.00 | $786.42 | $3.00 | $100.00 | $696.00 | $75.00 | $52.50 | $100.00 | $4,202.92 |
| 6 | $2,868.00 | $938.96 | $3.00 | $100.00 | $801.68 | $90.00 | $63.00 | $100.00 | $4,964.64 |
| 7 | $3,346.00 | $1,091.50 | $3.00 | $100.00 | $907.36 | $105.00 | $73.50 | $100.00 | $5,726.36 |
| 8 | $3,824.00 | $1,244.04 | $3.00 | $100.00 | $1,013.04 | $120.00 | $84.00 | $100.00 | $6,488.08 |
| 9 | $4,302.00 | $1,396.58 | $3.00 | $100.00 | $1,118.72 | $135.00 | $94.50 | $100.00 | $7,249.80 |
| 10 | $4,780.00 | $1,549.12 | $3.00 | $100.00 | $1,224.40 | $150.00 | $105.00 | $100.00 | $8,011.52 |
| 11 | $5,258.00 | $1,701.66 | $3.00 | $100.00 | $1,344.95 | $150.00 | $115.50 | $100.00 | $8,773.11 |
| 12 | $5,736.00 | $1,854.20 | $3.00 | $100.00 | $4,465.50 | $150.00 | $126.00 | $100.00 | $9,534.70 |
| 13 | $6,214.00 | $2,006.74 | $3.00 | $100.00 | $1,586.05 | $150.00 | $126.00 | $100.00 | $10,285.79 |
| 14 | $6,692.00 | $2,159.28 | $3.00 | $100.00 | $1,706.60 | $150.00 | $126.00 | $100.00 | $11,036.88 |
| 15 | $7,170.00 | $2,311.82 | $3.00 | $100.00 | $1,827.15 | $150.00 | $126.00 | $100.00 | $11,787.97 |
| 16 | $7,648.00 | $2,311.82 | $3.00 | $100.00 | $1,947.70 | $150.00 | $126.00 | $100.00 | $12,386.52 |
| 17 | $8,126.00 | $2,311.82 | $3.00 | $100.00 | $2,068.25 | $150.00 | $126.00 | $100.00 | $12,985.07 |
| 18 | $8,604.00 | $2,311.82 | $3.00 | $100.00 | $2,188.80 | $150.00 | $126.00 | $100.00 | $13,583.62 |
| 19 | $9,082.00 | $2,311.82 | $3.00 | $100.00 | $2,309.35 | $150.00 | $126.00 | $100.00 | $14,182.17 |
| 20 | $9,560.00 | $2,311.82 | $3.00 | $100.00 | $2,429.90 | $150.00 | $126.00 | $100.00 | $14,780.72 |
- 1
15 SCH or more pay $2,311.82/SEM based on flat rate at 15 SCH's
Add $478.00 tuition and $120.55 University Services fee for each hour over 20. Other fees remain the same.
Minimum Tuition: $478.00
Reinstatement fee: $363. 3-Peat Fee: $100 per semester credit hour
The University reserves the right to change fees upon board approval.
- 2
The Total includes a Student Union Fee of $100.00 per semester.
Undergraduate (Summer - 10 Week and 5 or 8 Week Parts of Term)
| Hours | Tuition1 | Designated Tuition2 | International Ed Fee | Rec Sports Fee | University Services Fee | Student Services Fee | Athletics Fee | Student Union Fee | Total |
|---|---|---|---|---|---|---|---|---|---|
| 1 | $478.00 | $176.26 | $3.00 | $50.00 | $273.28 | $15.00 | $10.50 | $50.00 | $1,056.04 |
| 2 | $956.00 | $328.80 | $3.00 | $50.00 | $378.96 | $30.00 | $21.00 | $50.00 | $1,817.76 |
| 3 | $1,434.00 | $481.34 | $3.00 | $50.00 | $484.64 | $45.00 | $31.50 | $50.00 | $2,579.48 |
| 4 | $1,912.00 | $633.88 | $3.00 | $50.00 | $590.32 | $60.00 | $42.00 | $50.00 | $3,341.20 |
| 5 | $2,390.00 | $786.42 | $3.00 | $50.00 | $694.86 | $75.00 | $52.50 | $50.00 | $4,102.92 |
| 6 | $2,868.00 | $938.96 | $3.00 | $50.00 | $801.68 | $90.00 | $63.00 | $50.00 | $4,864.64 |
| 7 | $3,346.00 | $1,091.50 | $3.00 | $50.00 | $907.36 | $105.00 | $73.50 | $50.00 | $5,626.36 |
| 8 | $3,824.00 | $1,244.04 | $3.00 | $50.00 | $1,013.04 | $120.00 | $84.00 | $50.00 | $6,388.08 |
| 9 | $4,302.00 | $1,396.58 | $3.00 | $50.00 | $1,118.72 | $135.00 | $94.50 | $50.00 | $7,149.80 |
| 10 | $4,780.00 | $1,549.12 | $3.00 | $50.00 | $1,224.40 | $150.00 | $105.00 | $50.00 | $7,911.52 |
| 11 | $5,258.00 | $1,701.66 | $3.00 | $50.00 | $1,344.95 | $150.00 | $115.50 | $50.00 | $8,673.11 |
| 12 | $5,736.00 | $1,854.20 | $3.00 | $50.00 | $1,465.50 | $150.00 | $126.00 | $50.00 | $9,434.70 |
| 13 | $6,214.00 | $2,006.74 | $3.00 | $50.00 | $1,586.05 | $150.00 | $126.00 | $50.00 | $10,185.79 |
| 14 | $6,580.00 | $2,159.28 | $3.00 | $50.00 | $1,706.60 | $150.00 | $126.00 | $50.00 | $10,824.88 |
| 15 | $7,170.00 | $2,311.82 | $3.00 | $50.00 | $1,827.15 | $150.00 | $126.00 | $50.00 | $11,687.97 |
| 16 | $7,648.00 | $2,311.82 | $3.00 | $50.00 | $1,947.70 | $150.00 | $126.00 | $50.00 | $12,286.52 |
| 17 | $8,126.00 | $2,311.82 | $3.00 | $50.00 | $2,068.25 | $150.00 | $126.00 | $50.00 | $12,885.07 |
| 18 | $8,604.00 | $2,311.82 | $3.00 | $50.00 | $2,188.80 | $150.00 | $126.00 | $50.00 | $13,483.62 |
| 19 | $9,082.00 | $2,311.82 | $3.00 | $50.00 | $2,309.29 | $150.00 | $126.00 | $50.00 | $14,082.17 |
| 20 | $9,560.00 | $2,311.82 | $3.00 | $50.00 | $2,429.90 | $150.00 | $126.00 | $50.00 | $14,680.72 |
- 1
15 SCH or more pay $2,306.36/SEM based on flat rate at 15 SCH's
Add $470.00 tuition and $120.67 University Services fee for each hour over 20. Other fees remain the same.
Minimum Tuition: $470.00
Reinstatement fee: $363.00 / 3-Peat Fee: $100 per semester credit hour
The University reserves the right to change fees upon board approval.
- 2
The Total includes a Student Union Fee of $50.00 per semester.