Claude Sonnet 5 vs DeepSeek V4.1 Flash
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% / 99.4% | 100.0% / 99.9% | 99.0% / 99.5% | 93.6% / 98.3% | 98.7% / 99.4% |
| Email triage | 98.2% / 97.6% | 98.2% / 97.4% | 97.9% / 96.3% | — | — |
| Personal data detection | 99.7% / 99.6% | 98.9% / 99.7% | 99.7% / 99.8% | — | — |
| Contract clauses | 100.0% / 100.0% | 100.0% / 100.0% | 98.2% / 97.2% | — | — |
Correct fields: Claude Sonnet 5 / DeepSeek V4.1 Flash; the better one in bold. Click a cell to see the details.
Invoice extraction · English (US) (150 documents)
Claude Sonnet 5 is more accurate by 0.4 pp. DeepSeek V4.1 Flash is 17× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 99.8% | 99.4% |
| Error-free documents | 99% | 93% |
| Per 1,000 documents | $8.84 | $0.52 |
| To fix / 1,000 | 13 | 67 |
| Speed (median) | 3.2 sec | 5.7 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Supplier | 100.0% | 100.0% |
| Supplier ID (EIN, IČO…) | 100.0% | 100.0% |
| Invoice number | 100.0% | 100.0% |
| Payment reference | 100.0% | 96.7% |
| Invoice date | 100.0% | 100.0% |
| Due date | 100.0% | 100.0% |
| Net by tax rate | 98.7% | 100.0% |
| Tax by rate | 99.3% | 100.0% |
| Total | 100.0% | 100.0% |
| Currency | 100.0% | 99.3% |
| Bank account | 100.0% | 97.3% |
Documents where they differ
- Reid Office Products LLC · A-003849 · Scan · Claude Sonnet 5 11/11, DeepSeek V4.1 Flash 10/11
- Austin Landscaping Inc. · INV-17836 · Scan · Claude Sonnet 5 11/11, DeepSeek V4.1 Flash 10/11
Invoice extraction · Czech (150 documents)
Claude Sonnet 5 is more accurate by 0.1 pp. DeepSeek V4.1 Flash is 19× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 100.0% | 99.9% |
| Error-free documents | 100% | 99% |
| Per 1,000 documents | $9.41 | $0.50 |
| To fix / 1,000 | 0 | 13 |
| Speed (median) | 3.6 sec | 5.0 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Supplier | 100.0% | 99.3% |
| Supplier ID (EIN, IČO…) | 100.0% | 100.0% |
| VAT ID | 100.0% | 100.0% |
| Invoice number | 100.0% | 100.0% |
| Payment reference | 100.0% | 100.0% |
| Invoice date | 100.0% | 100.0% |
| Tax point | 100.0% | 100.0% |
| Due date | 100.0% | 100.0% |
| Net by tax rate | 100.0% | 100.0% |
| Tax by rate | 100.0% | 100.0% |
| Total | 100.0% | 100.0% |
| Currency | 100.0% | 100.0% |
| Bank account | 100.0% | 99.3% |
Documents where they differ
- Michaela Strnadová · 25600363 · Scan · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
Invoice extraction · German (150 documents)
DeepSeek V4.1 Flash is more accurate by 0.6 pp. DeepSeek V4.1 Flash is 18.4× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 99.0% | 99.5% |
| Error-free documents | 87% | 94% |
| Per 1,000 documents | $10.42 | $0.57 |
| To fix / 1,000 | 133 | 60 |
| Speed (median) | 3.8 sec | 6.4 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Supplier | 100.0% | 99.3% |
| Supplier ID (EIN, IČO…) | 100.0% | 98.7% |
| VAT ID | 100.0% | 99.3% |
| Invoice number | 100.0% | 100.0% |
| Payment reference | 100.0% | 100.0% |
| Invoice date | 99.3% | 100.0% |
| Tax point | 100.0% | 99.3% |
| Due date | 100.0% | 99.3% |
| Net by tax rate | 89.3% | 100.0% |
| Tax by rate | 100.0% | 100.0% |
| Total | 100.0% | 100.0% |
| Currency | 100.0% | 100.0% |
| Bank account | 98.0% | 98.0% |
Documents where they differ
- Zimmermann & Schulz GmbH · RE11274 · Scan · Claude Sonnet 5 12/13, DeepSeek V4.1 Flash 13/13
- Malerbetrieb Otfried Haas · RE-2025-00168 · Scan · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Christoph Haas – Hausmeisterservice · 2025-1432 · Clean image · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Südform AG · 2025-0307 · PDF text · Claude Sonnet 5 12/13, DeepSeek V4.1 Flash 13/13
- Wesermetall GmbH · RE2501375 · Scan · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Zimmermann UG (haftungsbeschränkt) · GS10958 · Clean image · Claude Sonnet 5 12/13, DeepSeek V4.1 Flash 13/13
Invoice extraction · Spanish (100 documents)
DeepSeek V4.1 Flash is more accurate by 4.6 pp. DeepSeek V4.1 Flash is 16.8× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 93.6% | 98.3% |
| Error-free documents | 77% | 77% |
| Per 1,000 documents | $11.89 | $0.71 |
| To fix / 1,000 | 230 | 228 |
| Speed (median) | 4.0 sec | 5.8 sec |
| Valid answers | 95.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Supplier | 94.0% | 93.7% |
| Supplier ID (EIN, IČO…) | 95.0% | 100.0% |
| VAT ID | 95.0% | 100.0% |
| Invoice number | 95.0% | 100.0% |
| Payment reference | 94.0% | 97.5% |
| Invoice date | 95.0% | 100.0% |
| Tax point | 95.0% | 98.7% |
| Due date | 95.0% | 100.0% |
| Net by tax rate | 79.0% | 88.6% |
| Tax by rate | 95.0% | 100.0% |
| Total | 95.0% | 100.0% |
| Currency | 95.0% | 100.0% |
| Bank account | 95.0% | 98.7% |
Documents where they differ
- Losa Comunicación S.L. · A-2026-0862 · PDF text · Claude Sonnet 5 0/13, DeepSeek V4.1 Flash 13/13
- Centro de Formación del Sur S.L. · F2026-0167 · PDF text · Claude Sonnet 5 0/13, DeepSeek V4.1 Flash 13/13
- Leyre Lladó Vall · F2025-1476 · Photo · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Goñi Logística S.L. · R-2025/1460 · Scan · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Centro de Formación Mediterránea S.L. · 2026/0876 · Scan · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Onofre Diez Guitart · R-2025/1100 · Clean image · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
Invoice extraction · French (97 documents)
DeepSeek V4.1 Flash is more accurate by 0.7 pp. DeepSeek V4.1 Flash is 17× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 98.7% | 99.4% |
| Error-free documents | 96% | 92% |
| Per 1,000 documents | $11.02 | $0.65 |
| To fix / 1,000 | 41 | 81 |
| Speed (median) | 4.4 sec | 5.7 sec |
| Valid answers | 99.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Supplier | 99.0% | 100.0% |
| Supplier ID (EIN, IČO…) | 99.0% | 100.0% |
| VAT ID | 99.0% | 98.7% |
| Invoice number | 99.0% | 100.0% |
| Payment reference | 97.9% | 98.7% |
| Invoice date | 99.0% | 100.0% |
| Tax point | 99.0% | 100.0% |
| Due date | 99.0% | 100.0% |
| Net by tax rate | 96.9% | 100.0% |
| Tax by rate | 99.0% | 100.0% |
| Total | 99.0% | 100.0% |
| Currency | 99.0% | 100.0% |
| Bank account | 97.9% | 94.6% |
Documents where they differ
- Établissements Bertrand SASU · F2025-0066 · Scan · Claude Sonnet 5 11/13, DeepSeek V4.1 Flash 12/13
- Couverture Durand SA · F-11179 · Photo · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
Email triage · English (US) (150 documents)
Claude Sonnet 5 is more accurate by 0.6 pp. DeepSeek V4.1 Flash is 17.2× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 98.2% | 97.6% |
| Error-free documents | 84% | 79% |
| Per 1,000 documents | $4.01 | $0.23 |
| To fix / 1,000 | 160 | 213 |
| Speed (median) | 3.8 sec | 3.8 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Category | 100.0% | 100.0% |
| Priority | 97.3% | 96.7% |
| Sentiment | 86.7% | 82.0% |
| 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
- Russell Bates · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Allison Floyd · Email · Claude Sonnet 5 8/9, DeepSeek V4.1 Flash 9/9
- Robert Lewis · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Angela Harmon · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
Email triage · Czech (150 documents)
Claude Sonnet 5 is more accurate by 0.7 pp. DeepSeek V4.1 Flash is 16.6× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 98.2% | 97.4% |
| Error-free documents | 83% | 77% |
| Per 1,000 documents | $4.91 | $0.30 |
| To fix / 1,000 | 167 | 227 |
| Speed (median) | 4.7 sec | 4.2 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Category | 100.0% | 100.0% |
| Priority | 96.0% | 98.7% |
| Sentiment | 87.3% | 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
- Lucie Kašparová · Email · Claude Sonnet 5 8/9, DeepSeek V4.1 Flash 9/9
- Ignác Bartoš · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Simona Kolářová · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Petra Šťastná · Email · Claude Sonnet 5 8/9, DeepSeek V4.1 Flash 9/9
- Natálie Kratochvílová · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Šimon Beran · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Vanda Vacková · Email · Claude Sonnet 5 8/9, DeepSeek V4.1 Flash 9/9
- Růžena Sedláková · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
Email triage · German (150 documents)
Claude Sonnet 5 is more accurate by 1.5 pp. DeepSeek V4.1 Flash is 16.9× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 97.9% | 96.3% |
| Error-free documents | 81% | 68% |
| Per 1,000 documents | $5.11 | $0.30 |
| To fix / 1,000 | 187 | 324 |
| Speed (median) | 4.3 sec | 4.2 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Category | 100.0% | 100.0% |
| Priority | 96.0% | 97.2% |
| Sentiment | 84.7% | 69.7% |
| 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
- Rolf-Peter Metz · Email · Claude Sonnet 5 7/9, DeepSeek V4.1 Flash 8/9
- Sylwia Gerlach · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Irmela Warmer · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Roselinde Heinz · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Sibille Lehmann · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
- Augusta Lange · Email · Claude Sonnet 5 8/9, DeepSeek V4.1 Flash 9/9
- Margret Löchel · Email · Claude Sonnet 5 9/9, DeepSeek V4.1 Flash 8/9
Personal data detection · English (US) (150 documents)
Claude Sonnet 5 is more accurate by 0.1 pp. DeepSeek V4.1 Flash is 12.3× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 99.7% | 99.6% |
| Error-free documents | 98% | 97% |
| Per 1,000 documents | $3.50 | $0.29 |
| To fix / 1,000 | 20 | 27 |
| Speed (median) | 2.5 sec | 3.8 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Names | 100.0% | 98.7% |
| 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
- Margaret Mills · Text · Claude Sonnet 5 7/7, DeepSeek V4.1 Flash 6/7
Personal data detection · Czech (150 documents)
DeepSeek V4.1 Flash is more accurate by 0.8 pp. DeepSeek V4.1 Flash is 12.9× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 98.9% | 99.7% |
| Error-free documents | 92% | 98% |
| Per 1,000 documents | $4.06 | $0.31 |
| To fix / 1,000 | 80 | 20 |
| Speed (median) | 3.2 sec | 4.2 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Names | 96.7% | 100.0% |
| Email addresses | 100.0% | 100.0% |
| Phone numbers | 100.0% | 100.0% |
| Addresses | 97.3% | 98.0% |
| Dates of birth | 98.0% | 100.0% |
| National IDs | 100.0% | 100.0% |
| Bank accounts | 100.0% | 100.0% |
Documents where they differ
- Růžena Tichá · Text · Claude Sonnet 5 6/7, DeepSeek V4.1 Flash 7/7
- Jonáš Toman · Text · Claude Sonnet 5 6/7, DeepSeek V4.1 Flash 7/7
- Rudolf Konečný · Text · Claude Sonnet 5 6/7, DeepSeek V4.1 Flash 7/7
- Zikmund Sedláček · Text · Claude Sonnet 5 6/7, DeepSeek V4.1 Flash 7/7
Personal data detection · German (150 documents)
DeepSeek V4.1 Flash is more accurate by 0.1 pp. DeepSeek V4.1 Flash is 14.4× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 99.7% | 99.8% |
| Error-free documents | 98% | 99% |
| Per 1,000 documents | $4.40 | $0.31 |
| To fix / 1,000 | 20 | 13 |
| Speed (median) | 3.7 sec | 3.7 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Names | 98.7% | 100.0% |
| Email addresses | 100.0% | 100.0% |
| Phone numbers | 100.0% | 100.0% |
| Addresses | 100.0% | 98.7% |
| Dates of birth | 99.3% | 100.0% |
| National IDs | 100.0% | 100.0% |
| Bank accounts | 100.0% | 100.0% |
Documents where they differ
- Gunnar Zorbach · Text · Claude Sonnet 5 7/7, DeepSeek V4.1 Flash 6/7
Contract clauses · English (US) (150 documents)
Both are equally accurate. DeepSeek V4.1 Flash is 15.7× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 100.0% | 100.0% |
| Error-free documents | 100% | 100% |
| Per 1,000 documents | $5.04 | $0.32 |
| To fix / 1,000 | 0 | 0 |
| Speed (median) | 3.4 sec | 3.9 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| 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% | 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
Both models got the same number of fields right on every example document.
Contract clauses · Czech (150 documents)
Both are equally accurate. DeepSeek V4.1 Flash is 14.4× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 100.0% | 100.0% |
| Error-free documents | 100% | 100% |
| Per 1,000 documents | $6.05 | $0.42 |
| To fix / 1,000 | 0 | 0 |
| Speed (median) | 3.6 sec | 4.3 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| 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% | 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
Both models got the same number of fields right on every example document.
Contract clauses · German (150 documents)
Claude Sonnet 5 is more accurate by 1 pp. DeepSeek V4.1 Flash is 13.9× cheaper.
| Metric | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Correct fields | 98.2% | 97.2% |
| Error-free documents | 87% | 77% |
| Per 1,000 documents | $7.11 | $0.51 |
| To fix / 1,000 | 133 | 228 |
| Speed (median) | 4.3 sec | 4.6 sec |
| Valid answers | 100.0% | 100.0% |
Accuracy per field
| Field | Claude Sonnet 5 | DeepSeek V4.1 Flash |
|---|---|---|
| Provider | 100.0% | 100.0% |
| Provider ID | 87.3% | 81.4% |
| Client | 100.0% | 100.0% |
| Client ID | 89.3% | 82.8% |
| 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
- Hansawerk GmbH · Schreinerei Weber AG · Contract text · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 11/13
- Richter & Scholz e.K. · Köhler AG · Contract text · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 11/13
- Meyer AG · Hartmann GmbH · Contract text · Claude Sonnet 5 11/13, DeepSeek V4.1 Flash 13/13
- Winkler GmbH & Co. KG · Berger & Fuchs e.K. · Contract text · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Walter Systemtechnik GmbH & Co. KG · Weiß Handel GmbH · Contract text · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Möller GmbH & Co. KG · Schreinerei Kaiser GmbH · Contract text · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13
- Schuster Medien e.K. · Bäckerei Böhm GmbH · Contract text · Claude Sonnet 5 12/13, DeepSeek V4.1 Flash 13/13
- Fuchs GmbH · Hartmann & Brandt UG (haftungsbeschränkt) · Contract text · Claude Sonnet 5 13/13, DeepSeek V4.1 Flash 12/13