GPT-6 Luna vs Mistral Small 4

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	99.7% / 95.6%	99.3% / 93.6%	99.2% / 94.6%	99.1% / 91.9%	98.9% / 94.2%
Email triage	97.5% / 89.7%	97.9% / 87.7%	97.0% / 87.1%	—	—
Personal data detection	99.6% / 99.4%	99.6% / 98.8%	99.6% / 99.1%	—	—
Contract clauses	99.8% / 91.5%	100.0% / 99.0%	100.0% / 94.0%	—	—

Correct fields: GPT-6 Luna / Mistral Small 4; the better one in bold. Click a cell to see the details.

Invoice extraction · English (US) (150 documents)

GPT-6 Luna is more accurate by 4.1 pp. Mistral Small 4 is 1.2× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.7%	95.6%
Error-free documents	97%	58%
Per 1,000 documents	$0.51	$0.41
To fix / 1,000	33	420
Speed (median)	3.4 sec	1.8 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Supplier	100.0%	100.0%
Supplier ID (EIN, IČO…)	100.0%	99.3%
Invoice number	99.3%	100.0%
Payment reference	98.0%	87.3%
Invoice date	100.0%	97.3%
Due date	100.0%	98.7%
Net by tax rate	100.0%	72.0%
Tax by rate	100.0%	99.3%
Total	100.0%	100.0%
Currency	100.0%	99.3%
Bank account	99.3%	98.0%

Documents where they differ

Cochran-Graham Group LLC · A-007505 · Clean image · GPT-6 Luna 11/11, Mistral Small 4 9/11
Atlanta Office Products LLC · A-001328 · PDF text · GPT-6 Luna 11/11, Mistral Small 4 9/11
Reid Office Products LLC · A-003849 · Scan · GPT-6 Luna 11/11, Mistral Small 4 10/11
Miranda-Vega Group LLC · 4959 · PDF text · GPT-6 Luna 11/11, Mistral Small 4 10/11
Summit Services Inc. · INV-15230 · Scan · GPT-6 Luna 11/11, Mistral Small 4 10/11
Raleigh Engineering Inc. · INV253511 · Scan · GPT-6 Luna 10/11, Mistral Small 4 9/11
Hughes Janitorial Services Corp. · A-001911 · Scan · GPT-6 Luna 11/11, Mistral Small 4 10/11
Lutz & Sons, Inc. · A-008230 · Clean image · GPT-6 Luna 11/11, Mistral Small 4 10/11

Invoice extraction · Czech (150 documents)

GPT-6 Luna is more accurate by 5.6 pp. Mistral Small 4 is 1.2× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.3%	93.6%
Error-free documents	93%	56%
Per 1,000 documents	$0.51	$0.44
To fix / 1,000	67	440
Speed (median)	3.2 sec	2.0 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Supplier	95.3%	91.3%
Supplier ID (EIN, IČO…)	98.7%	92.7%
VAT ID	98.0%	94.0%
Invoice number	100.0%	100.0%
Payment reference	100.0%	97.3%
Invoice date	100.0%	98.0%
Tax point	100.0%	76.0%
Due date	99.3%	97.3%
Net by tax rate	100.0%	90.0%
Tax by rate	100.0%	94.7%
Total	100.0%	98.7%
Currency	100.0%	97.3%
Bank account	99.3%	90.0%

Documents where they differ

Sedláček s.r.o. · 2025/0774 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
Pavlík a Zeman s.r.o. · 25500457 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Hruška a Šťastný s.r.o. · 2025/0324 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Vilma Marešová · 2026/1216 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Erik Vítek · FV-2025-01059 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Ladislav Sýkora · 20261232 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Miloš Kadlec · FV2500859 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Kopecký s.r.o. · ZF-2025-00784 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 12/13

Invoice extraction · German (150 documents)

GPT-6 Luna is more accurate by 4.6 pp. Mistral Small 4 is 1.2× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.2%	94.6%
Error-free documents	91%	50%
Per 1,000 documents	$0.54	$0.44
To fix / 1,000	87	500
Speed (median)	3.7 sec	2.0 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Supplier	100.0%	98.6%
Supplier ID (EIN, IČO…)	98.7%	80.0%
VAT ID	99.3%	92.9%
Invoice number	99.3%	100.0%
Payment reference	100.0%	87.1%
Invoice date	98.7%	100.0%
Tax point	100.0%	87.9%
Due date	100.0%	98.6%
Net by tax rate	100.0%	94.3%
Tax by rate	100.0%	99.3%
Total	100.0%	100.0%
Currency	100.0%	100.0%
Bank account	94.0%	91.4%

Documents where they differ

Maurizio Schröder · RE10338 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 10/13
Druckerei Baumann GmbH · 2025-0324 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
Gebäudereinigung Klara Weiß · 2025-1126 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Schreinerei Ferdi Schuster · 2025/0939 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Isarplan e.K. · 2025/0849 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 12/13
Hoffmann UG (haftungsbeschränkt) · 2025/1479 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 12/13
Dachdeckerei Fischer GmbH · 2025/0014 · Scan · GPT-6 Luna 13/13, Mistral Small 4 12/13
Christoph Haas – Hausmeisterservice · 2025-1432 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 12/13

Invoice extraction · Spanish (100 documents)

GPT-6 Luna is more accurate by 7.1 pp. Mistral Small 4 is 1.2× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.1%	91.9%
Error-free documents	88%	31%
Per 1,000 documents	$0.55	$0.44
To fix / 1,000	120	691
Speed (median)	3.9 sec	2.2 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Supplier	99.0%	97.6%
Supplier ID (EIN, IČO…)	100.0%	98.8%
VAT ID	100.0%	53.6%
Invoice number	100.0%	100.0%
Payment reference	98.0%	88.1%
Invoice date	100.0%	100.0%
Tax point	100.0%	69.1%
Due date	100.0%	100.0%
Net by tax rate	100.0%	96.4%
Tax by rate	100.0%	97.6%
Total	100.0%	98.8%
Currency	100.0%	100.0%
Bank account	91.0%	95.2%

Documents where they differ

Leyre Lladó Vall · F2025-1476 · Photo · GPT-6 Luna 13/13, Mistral Small 4 10/13
Construcciones del Norte S.L.U. · PF25/0020 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Academia Checa S.L. · F2025-0208 · Clean image · GPT-6 Luna 12/13, Mistral Small 4 10/13
Centro de Formación Mediterránea S.L. · 2026/0876 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
Aguirre Formación S.L. · 2025/0652 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13
Centro de Formación del Sur S.L.U. · FV25-01115 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Coloma Servicios Informáticos S.L.U. · PRO-2025-0066 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
Centro de Formación Centro S.L.U. · A-2025-1405 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 11/13

Invoice extraction · French (98 documents)

GPT-6 Luna is more accurate by 4.7 pp. Mistral Small 4 is 1.3× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	98.9%	94.2%
Error-free documents	86%	50%
Per 1,000 documents	$0.57	$0.45
To fix / 1,000	143	500
Speed (median)	3.8 sec	2.1 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Supplier	99.0%	96.1%
Supplier ID (EIN, IČO…)	99.0%	93.4%
VAT ID	98.0%	93.4%
Invoice number	99.0%	100.0%
Payment reference	100.0%	85.5%
Invoice date	100.0%	100.0%
Tax point	100.0%	92.1%
Due date	100.0%	100.0%
Net by tax rate	100.0%	94.7%
Tax by rate	100.0%	100.0%
Total	100.0%	100.0%
Currency	100.0%	94.7%
Bank account	90.8%	75.0%

Documents where they differ

Occiservices SASU · AVO-2025-01209 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 10/13
Établissements Blanc SAS · F-11122 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
SA Établissements Gauthier · F2025-1451 · Photo · GPT-6 Luna 13/13, Mistral Small 4 11/13
Carrosserie Alain Meunier EI · FAC-2026-00869 · Clean image · GPT-6 Luna 12/13, Mistral Small 4 10/13
Maçonnerie Arnaude Dumont EI · FAC26021277 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
SAS Marie et Associés · FAC25070013 · Scan · GPT-6 Luna 13/13, Mistral Small 4 11/13
Établissements Legrand SA · F2025-1073 · PDF text · GPT-6 Luna 13/13, Mistral Small 4 12/13
Établissements Michel SA · FAC25100622 · Clean image · GPT-6 Luna 13/13, Mistral Small 4 12/13

Email triage · English (US) (150 documents)

GPT-6 Luna is more accurate by 7.8 pp. Mistral Small 4 is 1.4× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	97.5%	89.7%
Error-free documents	77%	37%
Per 1,000 documents	$0.13	$0.09
To fix / 1,000	227	627
Speed (median)	2.5 sec	0.8 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Category	100.0%	100.0%
Priority	98.0%	61.3%
Sentiment	79.3%	71.3%
Customer name	100.0%	100.0%
Order number	100.0%	100.0%
Invoice number	100.0%	100.0%
Amount	100.0%	99.3%
Currency	100.0%	99.3%
Deadline	100.0%	76.0%

Documents where they differ

Robert Lewis · Email · GPT-6 Luna 9/9, Mistral Small 4 6/9
Russell Bates · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Kyle Schwartz · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Jennifer Chapman · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Dale Sanchez · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Leah Douglas · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Angela Harmon · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Robert Taylor · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9

Email triage · Czech (150 documents)

GPT-6 Luna is more accurate by 10.2 pp. Mistral Small 4 is 1.5× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	97.9%	87.7%
Error-free documents	81%	32%
Per 1,000 documents	$0.18	$0.12
To fix / 1,000	187	685
Speed (median)	2.6 sec	0.8 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Category	100.0%	100.0%
Priority	98.7%	52.4%
Sentiment	82.7%	72.5%
Customer name	100.0%	98.7%
Order number	100.0%	100.0%
Invoice number	100.0%	100.0%
Amount	100.0%	98.0%
Currency	100.0%	98.0%
Deadline	100.0%	69.8%

Documents where they differ

Rostislav Novák · Email · GPT-6 Luna 9/9, Mistral Small 4 6/9
Milan Matějka · Email · GPT-6 Luna 9/9, Mistral Small 4 6/9
Milan Kašpar · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Eduard Stejskal · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Alexandr Kubíček · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Petra Šťastná · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Adam Vaněk · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Štěpánka Vítková · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9

Email triage · German (150 documents)

GPT-6 Luna is more accurate by 9.9 pp. Mistral Small 4 is 1.4× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	97.0%	87.1%
Error-free documents	73%	29%
Per 1,000 documents	$0.15	$0.11
To fix / 1,000	273	706
Speed (median)	2.8 sec	0.8 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Category	100.0%	100.0%
Priority	99.3%	55.2%
Sentiment	73.3%	65.0%
Customer name	100.0%	100.0%
Order number	100.0%	100.0%
Invoice number	100.0%	100.0%
Amount	100.0%	96.5%
Currency	100.0%	96.5%
Deadline	100.0%	70.6%

Documents where they differ

Berthold Anders · Email · GPT-6 Luna 9/9, Mistral Small 4 5/9
Rolf-Peter Metz · Email · GPT-6 Luna 8/9, Mistral Small 4 6/9
Swantje Noack · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Luzia Drewes · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Cynthia Hahn · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Sibille Lehmann · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Antonietta Wende · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9
Marta Kambs · Email · GPT-6 Luna 9/9, Mistral Small 4 7/9

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

GPT-6 Luna is more accurate by 0.2 pp. Mistral Small 4 is 1.4× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.6%	99.4%
Error-free documents	97%	96%
Per 1,000 documents	$0.11	$0.08
To fix / 1,000	27	40
Speed (median)	1.8 sec	0.8 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Names	98.7%	97.3%
Email addresses	100.0%	100.0%
Phone numbers	100.0%	100.0%
Addresses	98.7%	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

Christopher Scott · Text · GPT-6 Luna 7/7, Mistral Small 4 6/7
Justin Martinez · Text · GPT-6 Luna 6/7, Mistral Small 4 7/7
Denise Jones · Text · GPT-6 Luna 7/7, Mistral Small 4 6/7
David Fitzpatrick · Text · GPT-6 Luna 7/7, Mistral Small 4 6/7

Personal data detection · Czech (150 documents)

GPT-6 Luna is more accurate by 0.9 pp. Mistral Small 4 is 1.3× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.6%	98.8%
Error-free documents	97%	92%
Per 1,000 documents	$0.12	$0.09
To fix / 1,000	27	81
Speed (median)	1.8 sec	0.9 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Names	100.0%	94.0%
Email addresses	100.0%	100.0%
Phone numbers	100.0%	100.0%
Addresses	97.3%	98.7%
Dates of birth	100.0%	98.7%
National IDs	100.0%	100.0%
Bank accounts	100.0%	100.0%

Documents where they differ

Rudolf Konečný · Text · GPT-6 Luna 7/7, Mistral Small 4 5/7
Jonáš Toman · Text · GPT-6 Luna 6/7, Mistral Small 4 7/7

Personal data detection · German (150 documents)

GPT-6 Luna is more accurate by 0.5 pp. Mistral Small 4 is 1.3× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.6%	99.1%
Error-free documents	97%	94%
Per 1,000 documents	$0.12	$0.09
To fix / 1,000	27	65
Speed (median)	2.2 sec	0.9 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Names	100.0%	95.0%
Email addresses	100.0%	100.0%
Phone numbers	100.0%	100.0%
Addresses	97.3%	99.3%
Dates of birth	100.0%	100.0%
National IDs	100.0%	100.0%
Bank accounts	100.0%	99.3%

Documents where they differ

Rosi Karz · Text · GPT-6 Luna 7/7, Mistral Small 4 6/7
Gunnar Zorbach · Text · GPT-6 Luna 6/7, Mistral Small 4 7/7

Contract clauses · English (US) (150 documents)

GPT-6 Luna is more accurate by 8.3 pp. Mistral Small 4 is 1.2× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	99.8%	91.5%
Error-free documents	99%	43%
Per 1,000 documents	$0.20	$0.17
To fix / 1,000	13	567
Speed (median)	2.7 sec	1.1 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Provider	98.7%	43.3%
Provider ID	100.0%	100.0%
Client	98.7%	46.7%
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%	100.0%
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

Chambers & Sons, Corp. · Reed & Sons, LLC · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Santiago-Harris Group Co. · Columbus Printing Inc. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Murray Plumbing Inc. · Gray & Sons, Co. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Frye & Sons, Co. · Nunez-Smith Group Inc. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Kim Electric Co. · Ramos & Sons, Co. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Seattle Printing Inc. · Gutierrez Landscaping LLC · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Blue Ridge Services Corp. · Bishop-Kim Group LLC · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Page Printing LLC · Raleigh Printing Inc. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13

Contract clauses · Czech (150 documents)

GPT-6 Luna is more accurate by 1 pp. Mistral Small 4 is 1.2× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	100.0%	99.0%
Error-free documents	100%	92%
Per 1,000 documents	$0.27	$0.23
To fix / 1,000	0	80
Speed (median)	2.6 sec	1.2 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Provider	100.0%	95.3%
Provider ID	100.0%	100.0%
Client	100.0%	95.3%
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%	96.7%
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

Blažek s.r.o. · Moravec s.r.o. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Elektrotrade s.r.o. · Konečný a Dostál spol. s r.o. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 12/13
Bureš a Kadlec s.r.o. · Kříž s.r.o. · Contract text · GPT-6 Luna 13/13, Mistral Small 4 12/13

Contract clauses · German (150 documents)

GPT-6 Luna is more accurate by 6 pp. Mistral Small 4 is 1.3× cheaper.

Metric	GPT-6 Luna	Mistral Small 4
Correct fields	100.0%	94.0%
Error-free documents	100%	45%
Per 1,000 documents	$0.27	$0.21
To fix / 1,000	0	553
Speed (median)	3.0 sec	1.2 sec
Valid answers	100.0%	100.0%

Accuracy per field

Field	GPT-6 Luna	Mistral Small 4
Provider	100.0%	98.6%
Provider ID	100.0%	62.4%
Client	100.0%	98.6%
Client ID	100.0%	63.1%
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

Wesermetall e.K. · Weserform GmbH · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Hansawerk GmbH · Schreinerei Weber AG · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Schulz Systemtechnik GmbH · Elbdata GmbH · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Richter & Scholz e.K. · Köhler AG · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Richter & Albrecht e.K. · Elbmetall UG (haftungsbeschränkt) · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Meyer AG · Hartmann GmbH · Contract text · GPT-6 Luna 13/13, Mistral Small 4 11/13
Hahn & Schulz GmbH & Co. KG · Alpentec GmbH · Contract text · GPT-6 Luna 13/13, Mistral Small 4 12/13
Haustechnik Braun UG (haftungsbeschränkt) · Nordbau GmbH · Contract text · GPT-6 Luna 13/13, Mistral Small 4 12/13