Gemini 3.8 Flash vs Gemma 4 31B

Same documents, same prompt: where each model is right, what it really costs and how fast it answers.

At a glance

Task · documents	English (US)	Czech	German	Spanish	French
Invoice extraction	99.8% / 97.6%	100.0% / 96.1%	97.2% / 94.9%	95.9% / 95.4%	99.9% / 93.6%
Email triage	98.7% / 96.5%	99.2% / 97.1%	98.4% / 95.1%	—	—
Personal data detection	99.7% / 99.9%	99.5% / 99.8%	99.7% / 99.9%	—	—
Contract clauses	99.9% / 99.6%	100.0% / 100.0%	99.9% / 94.4%	—	—

Correct fields: Gemini 3.8 Flash / Gemma 4 31B; the better one in bold. Click a cell to see the details.

Invoice extraction · English (US) (150 documents)

Gemini 3.8 Flash is more accurate by 2.2 pp. Gemma 4 31B is 22.9× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.8%	97.6%
Error-free documents	98%	81%
Per 1,000 documents	$3.84	$0.17
To fix / 1,000	20	187
Speed (median)	3.2 sec	8.9 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Supplier	100.0%	99.3%
Supplier ID (EIN, IČO…)	100.0%	98.0%
Invoice number	100.0%	100.0%
Payment reference	100.0%	99.3%
Invoice date	100.0%	98.7%
Due date	100.0%	98.7%
Net by tax rate	100.0%	95.3%
Tax by rate	100.0%	98.7%
Total	100.0%	100.0%
Currency	100.0%	100.0%
Bank account	98.0%	86.0%

Documents where they differ

Harmon Logistics LLC · INV256017 · Scan · Gemini 3.8 Flash 11/11, Gemma 4 31B 8/11
Austin Landscaping Inc. · INV-17836 · Scan · Gemini 3.8 Flash 11/11, Gemma 4 31B 9/11
Gomez & Sons, LLC · 7855 · Scan · Gemini 3.8 Flash 11/11, Gemma 4 31B 9/11
Summit Services Inc. · INV-15230 · Scan · Gemini 3.8 Flash 11/11, Gemma 4 31B 10/11
Jennifer Moore · 5113 · Scan · Gemini 3.8 Flash 11/11, Gemma 4 31B 10/11
Mason-Nelson Group LLC · 2025-3952 · Photo · Gemini 3.8 Flash 11/11, Gemma 4 31B 10/11
Rose Lowery · INV-14797 · Clean image · Gemini 3.8 Flash 10/11, Gemma 4 31B 11/11
Sarah Villanueva · 2025-7876 · Clean image · Gemini 3.8 Flash 11/11, Gemma 4 31B 10/11

Invoice extraction · Czech (150 documents)

Gemini 3.8 Flash is more accurate by 3.9 pp. Gemma 4 31B is 20.1× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	100.0%	96.1%
Error-free documents	99%	67%
Per 1,000 documents	$4.26	$0.21
To fix / 1,000	7	333
Speed (median)	3.5 sec	10.4 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Supplier	99.3%	96.7%
Supplier ID (EIN, IČO…)	100.0%	93.3%
VAT ID	100.0%	96.7%
Invoice number	100.0%	100.0%
Payment reference	100.0%	96.0%
Invoice date	100.0%	96.0%
Tax point	100.0%	95.3%
Due date	100.0%	94.0%
Net by tax rate	100.0%	98.0%
Tax by rate	100.0%	97.3%
Total	100.0%	99.3%
Currency	100.0%	100.0%
Bank account	100.0%	86.7%

Documents where they differ

Jiřina Švecová · 25401227 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Bednář spol. s r.o. · 20250610 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Stejskal, v.o.s. · FV2600175 · Photo · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Ekolog s.r.o. · FV2600132 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Hruška a Šťastný s.r.o. · 2025/0324 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Moravská energetická spol. s r.o. · 25101373 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Michaela Strnadová · 25600363 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Sedlák s.r.o. · 20250158 · Photo · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13

Invoice extraction · German (150 documents)

Gemini 3.8 Flash is more accurate by 2.4 pp. Gemma 4 31B is 35.9× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	97.2%	94.9%
Error-free documents	96%	64%
Per 1,000 documents	$7.15	$0.20
To fix / 1,000	40	360
Speed (median)	4.7 sec	7.7 sec
Valid answers	97.3%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Supplier	97.3%	98.7%
Supplier ID (EIN, IČO…)	97.3%	99.3%
VAT ID	96.7%	94.0%
Invoice number	97.3%	99.3%
Payment reference	97.3%	98.7%
Invoice date	97.3%	87.3%
Tax point	97.3%	92.0%
Due date	97.3%	90.7%
Net by tax rate	96.7%	94.7%
Tax by rate	97.3%	97.3%
Total	97.3%	99.3%
Currency	97.3%	99.3%
Bank account	97.3%	82.7%

Documents where they differ

Gebäudereinigung Klara Weiß · 2025-1126 · PDF text · Gemini 3.8 Flash 0/13, Gemma 4 31B 13/13
Spedition Müller GmbH · 2026-1446 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 8/13
Wesermetall GmbH · RE2501375 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 9/13
Zimmermann & Schulz GmbH · RE11274 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 10/13
Dachdeckerei Fischer GmbH · 2025/0014 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 10/13
Schmidt & Bauer GmbH & Co. KG · RE-2025-01397 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 10/13
Richter GmbH & Co. KG · 2025-0509 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Nordtec GmbH & Co. KG · RE-2025-00909 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13

Invoice extraction · Spanish (100 documents)

Gemini 3.8 Flash is more accurate by 0.5 pp. Gemma 4 31B is 38.6× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	95.9%	95.4%
Error-free documents	95%	54%
Per 1,000 documents	$7.86	$0.20
To fix / 1,000	50	460
Speed (median)	5.3 sec	8.7 sec
Valid answers	96.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Supplier	95.0%	95.4%
Supplier ID (EIN, IČO…)	96.0%	93.1%
VAT ID	96.0%	98.9%
Invoice number	96.0%	100.0%
Payment reference	96.0%	95.4%
Invoice date	96.0%	98.9%
Tax point	96.0%	100.0%
Due date	96.0%	97.7%
Net by tax rate	96.0%	81.6%
Tax by rate	96.0%	100.0%
Total	96.0%	100.0%
Currency	96.0%	100.0%
Bank account	96.0%	79.3%

Documents where they differ

Climatización Levante S.L. · F2025-1305 · Scan · Gemini 3.8 Flash 0/13, Gemma 4 31B 12/13
Coloma Servicios Informáticos S.L.U. · PRO-2025-0066 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Talavera y Aller Asociados, S.L. · 2025/0610 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Distribuciones Mayo Santana, S.L.U. · A-2025-0563 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Talleres Rozas Zapata S.L. · FV25-01486 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Construcciones del Norte S.L.U. · PF25/0020 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Centro de Formación del Sur S.L.U. · F2025-1424 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Arranz e Hijos S.L. · F2026-0940 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13

Invoice extraction · French (100 documents)

Gemini 3.8 Flash is more accurate by 6.4 pp. Gemma 4 31B is 27.8× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.9%	93.6%
Error-free documents	99%	51%
Per 1,000 documents	$6.18	$0.22
To fix / 1,000	10	494
Speed (median)	5.2 sec	7.2 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Supplier	100.0%	96.6%
Supplier ID (EIN, IČO…)	100.0%	77.0%
VAT ID	100.0%	95.4%
Invoice number	100.0%	97.7%
Payment reference	99.0%	96.6%
Invoice date	100.0%	96.6%
Tax point	100.0%	94.3%
Due date	100.0%	96.6%
Net by tax rate	100.0%	93.1%
Tax by rate	100.0%	100.0%
Total	100.0%	100.0%
Currency	100.0%	98.9%
Bank account	100.0%	73.6%

Documents where they differ

Lefèvre & Fils SARL · FAC-2026-00198 · Photo · Gemini 3.8 Flash 13/13, Gemma 4 31B 8/13
Guérin & Fils EURL · 2026-05-688 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 10/13
SA Établissements Gauthier · F2025-1451 · Photo · Gemini 3.8 Flash 13/13, Gemma 4 31B 10/13
Nettoyage Christine Rivière EI · 2025-12-1174 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Établissements Bonnet EURL · AV-10599 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
SARL Garcia Informatique · F2025-0111 · Clean image · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Bernard et Associés SASU · FAC-2025-01115 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 11/13
Carrosserie Gauthier SASU · F-11079 · Scan · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13

Email triage · English (US) (150 documents)

Gemini 3.8 Flash is more accurate by 2.2 pp. Gemma 4 31B is 19.8× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	98.7%	96.5%
Error-free documents	89%	72%
Per 1,000 documents	$2.39	$0.12
To fix / 1,000	113	280
Speed (median)	2.2 sec	2.2 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Category	100.0%	100.0%
Priority	100.0%	85.3%
Sentiment	88.7%	83.3%
Customer name	100.0%	100.0%
Order number	100.0%	100.0%
Invoice number	100.0%	100.0%
Amount	100.0%	100.0%
Currency	100.0%	100.0%
Deadline	100.0%	100.0%

Documents where they differ

Daniel Stewart · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 7/9
Allison Floyd · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 7/9
Sheila Evans · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Gene Everett · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Jason Davis · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Christine Copeland · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Angela Harmon · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9

Email triage · Czech (150 documents)

Gemini 3.8 Flash is more accurate by 2.1 pp. Gemma 4 31B is 19.3× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.2%	97.1%
Error-free documents	93%	75%
Per 1,000 documents	$3.06	$0.16
To fix / 1,000	73	253
Speed (median)	2.6 sec	2.5 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Category	100.0%	100.0%
Priority	99.3%	85.3%
Sentiment	93.3%	88.7%
Customer name	100.0%	100.0%
Order number	100.0%	100.0%
Invoice number	100.0%	100.0%
Amount	100.0%	100.0%
Currency	100.0%	100.0%
Deadline	100.0%	100.0%

Documents where they differ

Alois Sedlák · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Lucie Kašparová · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Natálie Kratochvílová · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Šimon Beran · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Magdalena Sedláčková · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Ctibor Dušek · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Vanda Vacková · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Růžena Sedláková · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9

Email triage · German (150 documents)

Gemini 3.8 Flash is more accurate by 3.3 pp. Gemma 4 31B is 18.5× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	98.4%	95.1%
Error-free documents	85%	62%
Per 1,000 documents	$2.74	$0.15
To fix / 1,000	147	380
Speed (median)	2.9 sec	3.6 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Category	100.0%	100.0%
Priority	100.0%	78.0%
Sentiment	85.3%	78.0%
Customer name	100.0%	100.0%
Order number	100.0%	100.0%
Invoice number	100.0%	100.0%
Amount	100.0%	100.0%
Currency	100.0%	100.0%
Deadline	100.0%	100.0%

Documents where they differ

Alexej Sauer · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 7/9
Ibrahim Walter · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 7/9
Friedbert Hoffmann · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Sylwia Gerlach · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Benedikt Speer · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Cristina Krause · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Cynthia Hahn · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9
Roselinde Heinz · Email · Gemini 3.8 Flash 9/9, Gemma 4 31B 8/9

Personal data detection · English (US) (150 documents)

Gemma 4 31B is more accurate by 0.2 pp. Gemma 4 31B is 22.1× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.7%	99.9%
Error-free documents	98%	99%
Per 1,000 documents	$1.86	$0.08
To fix / 1,000	20	7
Speed (median)	1.9 sec	2.4 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Names	100.0%	100.0%
Email addresses	100.0%	100.0%
Phone numbers	100.0%	100.0%
Addresses	98.0%	99.3%
Dates of birth	100.0%	100.0%
National IDs	100.0%	100.0%
Bank accounts	100.0%	100.0%

Documents where they differ

Both models got the same number of fields right on every example document.

Personal data detection · Czech (150 documents)

Gemma 4 31B is more accurate by 0.3 pp. Gemma 4 31B is 18.4× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.5%	99.8%
Error-free documents	97%	99%
Per 1,000 documents	$2.19	$0.12
To fix / 1,000	33	13
Speed (median)	2.0 sec	2.9 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Names	98.7%	100.0%
Email addresses	100.0%	100.0%
Phone numbers	100.0%	100.0%
Addresses	98.0%	98.7%
Dates of birth	100.0%	100.0%
National IDs	100.0%	100.0%
Bank accounts	100.0%	100.0%

Documents where they differ

Both models got the same number of fields right on every example document.

Personal data detection · German (150 documents)

Gemma 4 31B is more accurate by 0.2 pp. Gemma 4 31B is 20.8× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.7%	99.9%
Error-free documents	98%	99%
Per 1,000 documents	$2.12	$0.10
To fix / 1,000	20	7
Speed (median)	2.3 sec	1.9 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Names	100.0%	100.0%
Email addresses	100.0%	100.0%
Phone numbers	100.0%	100.0%
Addresses	98.0%	99.3%
Dates of birth	100.0%	100.0%
National IDs	100.0%	100.0%
Bank accounts	100.0%	100.0%

Documents where they differ

Gunnar Zorbach · Text · Gemini 3.8 Flash 7/7, Gemma 4 31B 6/7

Contract clauses · English (US) (150 documents)

Gemini 3.8 Flash is more accurate by 0.3 pp. Gemma 4 31B is 13.7× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.9%	99.6%
Error-free documents	99%	97%
Per 1,000 documents	$2.47	$0.18
To fix / 1,000	7	27
Speed (median)	2.0 sec	2.5 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Provider	99.3%	98.0%
Provider ID	100.0%	100.0%
Client	99.3%	98.0%
Client ID	100.0%	100.0%
Contract type	100.0%	100.0%
Price (net)	100.0%	100.0%
Currency	100.0%	100.0%
Billing period	100.0%	100.0%
Effective date	100.0%	99.3%
End date	100.0%	100.0%
Notice period (months)	100.0%	100.0%
Late-payment penalty (% per day)	100.0%	100.0%
Governing law	100.0%	100.0%

Documents where they differ

Kim Electric Co. · Ramos & Sons, Co. · Contract text · Gemini 3.8 Flash 11/13, Gemma 4 31B 13/13

Contract clauses · Czech (150 documents)

Both are equally accurate. Gemma 4 31B is 12.2× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	100.0%	100.0%
Error-free documents	100%	99%
Per 1,000 documents	$3.09	$0.25
To fix / 1,000	0	7
Speed (median)	2.2 sec	6.0 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Provider	100.0%	100.0%
Provider ID	100.0%	100.0%
Client	100.0%	100.0%
Client ID	100.0%	100.0%
Contract type	100.0%	100.0%
Price (net)	100.0%	100.0%
Currency	100.0%	100.0%
Billing period	100.0%	100.0%
Effective date	100.0%	99.3%
End date	100.0%	100.0%
Notice period (months)	100.0%	100.0%
Late-payment penalty (% per day)	100.0%	100.0%
Governing law	100.0%	100.0%

Documents where they differ

Elektrotrade s.r.o. · Konečný a Dostál spol. s r.o. · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13

Contract clauses · German (150 documents)

Gemini 3.8 Flash is more accurate by 5.5 pp. Gemma 4 31B is 15.5× cheaper.

Metric	Gemini 3.8 Flash	Gemma 4 31B
Correct fields	99.9%	94.4%
Error-free documents	99%	27%
Per 1,000 documents	$3.42	$0.22
To fix / 1,000	7	727
Speed (median)	2.6 sec	2.6 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	Gemini 3.8 Flash	Gemma 4 31B
Provider	100.0%	100.0%
Provider ID	99.3%	100.0%
Client	100.0%	100.0%
Client ID	99.3%	100.0%
Contract type	100.0%	100.0%
Price (net)	100.0%	100.0%
Currency	100.0%	100.0%
Billing period	100.0%	100.0%
Effective date	100.0%	100.0%
End date	100.0%	100.0%
Notice period (months)	100.0%	100.0%
Late-payment penalty (% per day)	100.0%	27.3%
Governing law	100.0%	100.0%

Documents where they differ

Hahn GmbH · Bauer & Klein GmbH · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Wesermetall e.K. · Weserform GmbH · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Haustechnik Braun UG (haftungsbeschränkt) · Nordbau GmbH · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Hansawerk GmbH · Schreinerei Weber AG · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Maintec GmbH · Schreinerei Wagner GmbH · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Winkler & Beck e.K. · Meyer & Weber e.K. · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Kraus Consulting GmbH · Lange Consulting GmbH & Co. KG · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13
Hansametall GmbH & Co. KG · Roth & Schröder UG (haftungsbeschränkt) · Contract text · Gemini 3.8 Flash 13/13, Gemma 4 31B 12/13